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https://en.wikipedia.org/wiki/Rader%27s%20FFT%20algorithm | Rader's algorithm (1968), named for Charles M. Rader of MIT Lincoln Laboratory, is a fast Fourier transform (FFT) algorithm that computes the discrete Fourier transform (DFT) of prime sizes by re-expressing the DFT as a cyclic convolution (the other algorithm for FFTs of prime sizes, Bluestein's algorithm, also works by rewriting the DFT as a convolution).
Since Rader's algorithm only depends upon the periodicity of the DFT kernel, it is directly applicable to any other transform (of prime order) with a similar property, such as a number-theoretic transform or the discrete Hartley transform.
The algorithm can be modified to gain a factor of two savings for the case of DFTs of real data, using a slightly modified re-indexing/permutation to obtain two half-size cyclic convolutions of real data; an alternative adaptation for DFTs of real data uses the discrete Hartley transform.
Winograd extended Rader's algorithm to include prime-power DFT sizes , and today Rader's algorithm is sometimes described as a special case of Winograd's FFT algorithm, also called the multiplicative Fourier transform algorithm (Tolimieri et al., 1997), which applies to an even larger class of sizes. However, for composite sizes such as prime powers, the Cooley–Tukey FFT algorithm is much simpler and more practical to implement, so Rader's algorithm is typically only used for large-prime base cases of Cooley–Tukey's recursive decomposition of the DFT.
Algorithm
Begin with the definition of the discrete Fourier transform:
If N is a prime number, then the set of non-zero indices forms a group under multiplication modulo N. One consequence of the number theory of such groups is that there exists a generator of the group (sometimes called a primitive root, which can be found by exhaustive search or slightly better algorithms). This generator is an integer g such that for any non-zero index n and for a unique (forming a bijection from q to non-zero n). Similarly, for any non-zero index k and for a unique , where the negative exponent denotes the multiplicative inverse of . That means that we can rewrite the DFT using these new indices p and q as:
(Recall that xn and Xk are implicitly periodic in N, and also that (Euler's identity). Thus, all indices and exponents are taken modulo N as required by the group arithmetic.)
The final summation, above, is precisely a cyclic convolution of the two sequences aq and bq (of length N–1, because ) defined by:
Evaluating the convolution
Since N–1 is composite, this convolution can be performed directly via the convolution theorem and more conventional FFT algorithms. However, that may not be efficient if N–1 itself has large prime factors, requiring recursive use of Rader's algorithm. Instead, one can compute a length-(N–1) cyclic convolution exactly by zero-padding it to a length of at least 2(N–1)–1, say to a power of two, which can then be evaluated in O(N log N) time without the recursive application of Rader's algori |
https://en.wikipedia.org/wiki/OmniWeb | OmniWeb is a discontinued web browser that was developed and marketed by The Omni Group exclusively for Apple's macOS operating system. Though a stable version is no longer maintained, it is still available as a free download and unstable versions are still being released.
History
OmniWeb was originally developed by Omni Group for the NeXTSTEP platform, and was released by Lighthouse Design on March 17, 1995 after only one month's development time. As NeXTSTEP evolved into OPENSTEP and then Mac OS X, OmniWeb was updated to run on these platforms. These early versions of OmniWeb also run on Microsoft Windows through the Yellow Box or the OpenStep frameworks. After Lighthouse Design was bought by Sun Microsystems, the Omni Group released the product themselves, from version 2.5 onwards. From version 4.0 onwards, OmniWeb was developed solely for the OS X platform.
OmniWeb was developed using the Cocoa API which allow it to take full advantage of OS X features. It uses Quartz to render images and smooth text. It makes use of multiple processors if available, and features an interface that made use of Aqua UI features such as drawers, sheets, and customizable toolbars.
The Omni Group originally employed its own proprietary HTML layout engine that use standard API NSText components. However, this engine was very slow, particularly when scrolling, and was not fully compatible with the most recent web standards, such as Cascading Style Sheets. In OmniWeb version 4.5, the Omni Group adopted Apple's KHTML-based WebCore rendering engine, which was created by Apple for its Safari browser.
On August 11, 2004, the Omni Group released version 5.0 of OmniWeb which added a number of new features. The most notable addition was an unusual implementation of tabbed browsing, in which the tabs are displayed vertically in a drawer on the side of the window (including optional thumbnail pictures of the pages.) Despite a certain amount of controversy over the merits of a tab drawer over a tab toolbar, the feature persists through the final version.
On September 7, 2006, version 5.5 was released. Major new features include the use of a custom version of WebKit instead of WebCore, universal binary support, saving to web archive, support for user-defined style sheets, a "Select Next Link" feature, FTP folder display, ad-blocking improvements, updated localizations, and many other small changes and bug fixes.
OmniWeb was Omni Group's flagship app but as OS X web browsers improved—Apple eventually bundled Safari into OS X— and Omni successfully introduced other products such as OmniGraffle and OmniOutliner, OmniWeb's importance diminished. OmniWeb's price was successively lowered, first to $39.95, then on February 24, 2009, Omni Group announced that OmniWeb would be made available for free, a change from its previous price of $14.95. The Omni Group official website now states that the browser is no longer under active development.
Features
Separate window form editing |
https://en.wikipedia.org/wiki/Prime-factor%20FFT%20algorithm | The prime-factor algorithm (PFA), also called the Good–Thomas algorithm (1958/1963), is a fast Fourier transform (FFT) algorithm that re-expresses the discrete Fourier transform (DFT) of a size N = N1N2 as a two-dimensional N1×N2 DFT, but only for the case where N1 and N2 are relatively prime. These smaller transforms of size N1 and N2 can then be evaluated by applying PFA recursively or by using some other FFT algorithm.
PFA should not be confused with the mixed-radix generalization of the popular Cooley–Tukey algorithm, which also subdivides a DFT of size N = N1N2 into smaller transforms of size N1 and N2. The latter algorithm can use any factors (not necessarily relatively prime), but it has the disadvantage that it also requires extra multiplications by roots of unity called twiddle factors, in addition to the smaller transforms. On the other hand, PFA has the disadvantages that it only works for relatively prime factors (e.g. it is useless for power-of-two sizes) and that it requires more complicated re-indexing of the data based on the additive group isomorphisms. Note, however, that PFA can be combined with mixed-radix Cooley–Tukey, with the former factorizing N into relatively prime components and the latter handling repeated factors.
PFA is also closely related to the nested Winograd FFT algorithm, where the latter performs the decomposed N1 by N2 transform via more sophisticated two-dimensional convolution techniques. Some older papers therefore also call Winograd's algorithm a PFA FFT.
(Although the PFA is distinct from the Cooley–Tukey algorithm, Good's 1958 work on the PFA was cited as inspiration by Cooley and Tukey in their 1965 paper, and there was initially some confusion about whether the two algorithms were different. In fact, it was the only prior FFT work cited by them, as they were not then aware of the earlier research by Gauss and others.)
Algorithm
Let a polynomial and a principal th root of unity. We define the DFT of as the -tuple .
In other words,
for all .
For simplicity, we denote the transformation as .
The PFA relies on a coprime factorization of and turns into for some choices of 's where is the tensor product.
Mapping Based on CRT
For a coprime factorization , we have the Chinese remainder map from to with as its inverse where 's are the central orthogonal idempotent elements with .
Choosing (therefore, ), we rewrite as follows:
.
Finally, define and ,
we have
.
Therefore, we have the multi-dimensional DFT, .
As Algebra Isomorphisms
PFA can be stated in a high-level way in terms of algebra isomorphisms.
We first recall that for a commutative ring and a group isomorphism from to ,
we have the following algebra isomorphism
where refers to the tensor product of algebras.
To see how PFA works,
we choose and be additive groups.
We also identify as and as .
Choosing as the group isomorphism , we have the algebra isomorphism , or alternatively,
.
Now observe that is actually an alge |
https://en.wikipedia.org/wiki/Modula-3 | Modula-3 is a programming language conceived as a successor to an upgraded version of Modula-2 known as Modula-2+. While it has been influential in research circles (influencing the designs of languages such as Java, C#, Python and Nim) it has not been adopted widely in industry. It was designed by Luca Cardelli, James Donahue, Lucille Glassman, Mick Jordan (before at the Olivetti Software Technology Laboratory), Bill Kalsow and Greg Nelson at the Digital Equipment Corporation (DEC) Systems Research Center (SRC) and the Olivetti Research Center (ORC) in the late 1980s.
Modula-3's main features are modularity, simplicity and safety while preserving the power of a systems-programming language. Modula-3 aimed to continue the Pascal tradition of type safety, while introducing new constructs for practical real-world programming. In particular Modula-3 added support for generic programming (similar to templates), multithreading, exception handling, garbage collection, object-oriented programming, partial revelation, and explicit marking of unsafe code. The design goal of Modula-3 was a language that implements the most important features of modern imperative programming languages in quite basic forms. Thus allegedly dangerous and complicating features such as multiple inheritance and operator overloading were omitted.
Historical development
The Modula-3 project started in November 1986 when Maurice Wilkes wrote to Niklaus Wirth with some ideas for a new version of Modula. Wilkes had been working at DEC just prior to this point, and had returned to England and joined Olivetti's Research Strategy Board. Wirth had already moved on to Oberon, but had no problems with Wilkes's team continuing development under the Modula name. The language definition was completed in August 1988, and an updated version in January 1989. Compilers from DEC and Olivetti soon followed, and 3rd party implementations after that.
Its design was heavily influenced by work on the Modula-2+ language in use at SRC and at the Acorn Computers Research Center (ARC, later ORC when Olivetti acquired Acorn) at the time, which was the language in which the operating system for the DEC Firefly multiprocessor VAX workstation was written and in which the Acorn Compiler for Acorn C and Modula Execution Library (CAMEL) at ARC for the ARX operating system project of ARM based Acorn Archimedes range of computers was written. As the revised Modula-3 Report states, the language was influenced by other languages such as Mesa, Cedar, Object Pascal, Oberon and Euclid.
During the 1990s, Modula-3 gained considerable currency as a teaching language, but it was never widely adopted for industrial use. Contributing to this may have been the demise of DEC, a key Modula-3 supporter (especially when it ceased to maintain it effectively before DEC was sold to Compaq in 1998). In any case, in spite of Modula-3's simplicity and power, it appears that there was little demand for a procedural compiled language w |
https://en.wikipedia.org/wiki/Scandinavian%20Simvastatin%20Survival%20Study | The Scandinavian Simvastatin Survival Study (also known as the 4S study), was a multicentre, randomized, double-blind, placebo-controlled clinical trial, which provided the initial data that supported the use of the cholesterol-lowering drug, simvastatin, in people with a moderately raised cholesterol and coronary heart disease (CHD); that is people who had previously had a heart attack or angina. The study was sponsored by the pharmaceutical company Merck and enrolled 4,444 people from 94 centres in Scandinavia.
Before the 4S study, it was not proven that lowering cholesterol could prolong life in people who had CHD. The study concluded that secondary prevention with simvastatin in a high risk group with CHD reduced overall mortality by 30%. Published in The Lancet in 1994, it is considered a "landmark paper".
Objective
The 4S multicentre, randomized, double-blind, placebo-controlled clinical trial enrolled 4,444 people chosen from 7,027 people who had been followed up for two months after being given dietary advice. The objective of the study was to assess the effect of a cholesterol-lowering drug called simvastatin on mortality and morbidity in people with a history of a previous heart attack or angina, who also had a moderately raised cholesterol; between 5.5 and 8.0 mmol/L.
A second objective was to investigate whether the incidence of major coronary artery disease events (fatal and nonfatal myocardial infarction and sudden death) could be reduced with simvastatin.
Study details
The participants, all at high risk of death from CHD and death in general, were selected from 94 clinical centers in Denmark, Finland, Iceland, Norway, and Sweden from 1988 to 1989, and were aged between 35 and 70 years, with the average age being 59. Of the 4,444 people enrolled in the study, 3,617 were men and 827 women, 2,223 were randomly assigned a placebo and 2,221 were given 20 to 40 mg of simvastatin daily. The plan was to follow the participants for a minimum of three years or until such a time as total mortality reached 440 deaths. In practice, the study carried for a median period of 5.4 years.
Results
After 5.4 years, compared to the group that were given placebo, the simvastatin group demonstrated a 35% reduction in LDL-C and 30% reduction in overall mortality. The risk of hospital-verified non-fatal myocardial infarction reduced by 37% and fatal and non-fatal cerebrovascular events (stroke and TIA) lessened by 28%. 30 people would need to be treated with simvastatin to prevent one death; number needed to treat around 30. There were no extra deaths from other non-cardiac causes such as cancer or trauma. The trial also showed benefits in diabetes, women and older people.
A follow-up of treatment with simvastatin for up to eight years was published in 2000. Ten years after the start of the 4S trial, a follow-up study published on 28 August 2004 in The Lancet, revealed that of those 2,221 people who continued to take simvastatin, there was a further |
https://en.wikipedia.org/wiki/Bonjour%20%28software%29 | Bonjour is Apple's implementation of zero-configuration networking (zeroconf), a group of technologies that includes service discovery, address assignment, and hostname resolution. Bonjour locates devices such as printers, other computers, and the services that those devices offer on a local network using multicast Domain Name System (mDNS) service records.
The software comes built-in with Apple's macOS and iOS operating systems. Bonjour can also be installed onto computers running Microsoft Windows. Bonjour components may also be included within other software such as iTunes and Safari.
After its introduction in 2002 with Mac OS X 10.2 as Rendezvous, the software was renamed in 2005 to Bonjour following an out-of-court trademark dispute settlement.
Overview
Bonjour provides a general method to discover services on a local area network. The software is widely used throughout macOS, and allows users to set up a network without any configuration. it is used to find printers and file-sharing servers.
Notable applications using Bonjour include:
iTunes to find shared music
iPhoto to find shared photos
Adium, Pidgin, Vine Server, and Elgato EyeTV to communicate with multiple clients
SubEthaEdit to find document collaborators
Solidworks and PhotoView 360 used for managing licenses
Things and OmniFocus to synchronize projects and tasks across the Mac desktop and the iPad, iPhone or iPod touch
Safari to find local web servers and configuration pages for local devices
Software such as Bonjour Browser or iStumbler, both for macOS, can be used to view all services declared by these applications. Apple's "Remote" application for iPhone and iPod Touch also uses Bonjour to establish connection to iTunes libraries via Wi-Fi.
Bonjour only works within a single broadcast domain, which is usually a small area, without special DNS configuration. macOS, Bonjour for Windows and AirPort Base Stations may be configured to use Wide Area Bonjour which allows for wide area service discovery via an appropriately configured DNS server.
Applications generally implement Bonjour services using standard TCP/IP calls, rather than in the operating system. Although macOS provides various Bonjour services, Bonjour also works on other operating systems. Apple has made the source code of the Bonjour multicast DNS responder, the core component of service discovery, available as a Darwin open source project. The project provides source code to build the responder daemon for a wide range of platforms, including Mac OS 9, macOS, Linux, *BSD, Solaris, VxWorks, and Windows. Apple also provides a user-installable set of services called Bonjour for Windows and Java libraries.
Licensing
Bonjour is released under a terms-of-limited-use license by Apple. It is freeware for clients, though developers and software companies who wish to redistribute it as part of a software package or use the Bonjour logo may need a licensing agreement. The source code for mDNSResponder is available under |
https://en.wikipedia.org/wiki/ReBoot | ReBoot is a Canadian computer-animated TV series that originally aired on YTV from 1994 until 2001. It was produced by Vancouver-based Mainframe Entertainment, Alliance Distribution and BLT Productions. The animated series was created by Gavin Blair, Ian Pearson, Phil Mitchell, and John Grace, with the visuals designed by Brendan McCarthy after an initial attempt by Ian Gibson. It is notable for being one of the first made-for-television CGI series.
Overview
The show follows the adventures of a Guardian named Bob and his companions Enzo and Dot Matrix as they work to keep the computer system of Mainframe safe from the viruses known as Megabyte and Hexadecimal, in addition to other threats. One recurring plot thread: when the User loads a game, an electrical violet cube lowers onto part of the city. Anyone trapped inside becomes NPCs and have the chance to stop the User. If the User wins, the area is destroyed and the residents reduced to leech like creatures called Nulls. The setting is in the inner world of a computer system known by its inhabitants as Mainframe. It was deliberately chosen due to technological constraints at the time, as the fictional computer world allowed for blocky looking models and mechanical animation.
Reimagining
A reimagined, live-action/CGI-animated series, ReBoot: The Guardian Code, was announced in 2015, and the first ten episodes premiered on Netflix worldwide (excluding Canada) on March 30, 2018. YTV aired all 20 episodes from June 4 until July 5, 2018.
The series follows four teenaged gamers, who are members of an online game's highest-scoring team. Vera is an artificial intelligence who has recruited the team as "Guardians" to physically enter and protect cyberspace. The Guardians battle the Sourcerer, a human hacker. Primary characters from the original series, such as Bob, Dot, and Enzo, are minor characters and only appear in one episode.
Cast and characters
The main characters included:
Bob – Guardian 452. He acts as the Guardian of Mainframe.
Phong – The original of Mainframe. Phong serves as a mentor and adviser to its inhabitants and works with Bob in defense of the system.
Dot Matrix – Initially owns a local diner and many other "businesses" (as seen at the end of the third episode of the first season). She takes over as in the third season.
Enzo Matrix – Dot's younger brother who idolized Bob as a hero. Enzo later grows up to become the renegade simply known as Matrix. Enzo's name is not a reference to computer terminology but instead the real-world Italian name "Enzo", as suggested to the co-creators by Chris Brough.
Frisket – A red and yellow dog. He is feral, incredibly strong, and only listens to Enzo.
AndrAIa – A game sprite and friend (and later girlfriend) of Enzo introduced in season 2. She came from a 'Treasure of Atlantis' game and as such wears many seashells on her outfit. The "AI" in her name refers to artificial intelligence.
Megabyte (Gigabyte) – A "command and conquer, and infec |
https://en.wikipedia.org/wiki/Reboot%20%28disambiguation%29 | A reboot is the process of restarting a computer system.
Reboot may also refer to:
Arts, entertainment, and media
Reboot (fiction), to discard all previous continuity in a fiction series and start anew
Music
Reboot (Brooks & Dunn album), 2019
Reboot (London album), 2012
ReBoot (Sam Brown album), 2000
Reboot (Wonder Girls album), 2015
Reboot (Treasure album), 2023
Re-boot (album), a 2019 album by Golden Child
Re-Boot: Live '98, a 1998 album by the band Front 242
"Reboot" (song), by Tohoshinki, 2017
"[Reboot]", a single from the 2019 Waterparks album, Fandom
Television
ReBoot, a Canadian CGI-animated television series which debuted in 1994
ReBoot: The Guardian Code, a CGI / live-action reimagining of the 1994 series released in 2018
Reboot (Adventure Time), a 2016 episode of Adventure Time
Reboot (2022 TV series), a 2022 TV series
Other
ReBoot (video game), a 1998 video game based on the television series
Reboot (novel), a novel by Amy Tintera
See also
Booting
Reset (disambiguation)
Restart (disambiguation)
Revival (television) |
https://en.wikipedia.org/wiki/Watto | Watto is a fictional character in the Star Wars franchise, featured in the films The Phantom Menace and Attack of the Clones. He is computer-generated and is voiced by voice actor Andy Secombe. He is a mean-tempered, greedy Toydarian, and owner of a second-hand goods store in Mos Espa on the planet Tatooine. Among Watto's belongings are the slaves Shmi Skywalker and her son; Anakin. He acquires them after winning a podracing bet with Gardulla the Hutt, and he puts them both to work in his store. Anakin demonstrates an incredible aptitude for equipment repair, and Watto decides to profit from it by having the boy fix various broken equipment in the store. He eventually loses Anakin in a podracing bet with Qui-Gon Jinn when he bets on a competitor, Sebulba, who is defeated by Anakin.
Concept and creation
George Lucas was specific with the concept art team about what features he envisioned for Watto. Design director Doug Chiang described the character's design as "this conglomeration of odd things that really didn't fit, but that in the end gave him a very unique and powerful personality". Lucas dismissed concepts including a pudgy parrot by Terryl Whitlatch (though Whitlatch recalls one of her designs influencing the direction for the character) and a four-armed beast with a cigar by Iain Craig. Chiang repurposed the head from one of his early Neimoidian designs, featuring a hooked trunk and crooked teeth, and added hummingbird wings, meeting Lucas's approval. Additionally, Chiang gave Watto a vest and a tool belt, only asking for webbed feet and pants. Modeling supervisor Geoff Campell was skeptical of having a chubby alien with wings, so it was imagined that the Toydarians are filled with gas, with the wings propelling them instead of supporting their weight. Animation supervisor Rob Coleman realized that the alien's teeth would need some modification, as the craggy teeth made lip-syncing difficult. To solve the problem, Coleman broke off one of Watto's incisors, giving him a "corner-of-the-mouth" vernacular. His expressions were based on video footage of voice actor Andy Secombe, photographs of Coleman imitating the character, and modeler Steve Alpin saying Watto's lines to a mirror. Alec Guinness performing as Fagin in Oliver Twist was used as an influence in the character's development. The sound of his wings flapping is a looped recording of sound designer Ben Burtt opening and closing an umbrella.
Appearances
Watto first appears in Star Wars: Episode I – The Phantom Menace, the first title chronologically in the Star Wars series. He has both an ability for haggling and a resistance to the "Jedi mind trick", a technique used to persuade people. He is both a junk dealer and slave owner on the planet Tatooine, possessing both Shmi Skywalker and her son Anakin. When challenged to a bet for Anakin's freedom by Qui-Gon Jinn, Watto agrees. After Anakin beats Sebulba (whom Watto bets on), a competing racer that he challenged throughout the race he |
https://en.wikipedia.org/wiki/Panasonic%20CD%20interface | The Panasonic CD interface, also known as the MKE CD interface (for Matsushita Kotobuki Electronics), SLCD or simply Panasonic, is a proprietary computer interface for connecting a CD-ROM drive to an IBM PC compatible computer. It was used briefly in the early 1990s, and is no longer in production.
The interface is similar in physical format to an IDE, and an IDE cable may be used; however, the CD-ROM drive cannot be connected to the IDE bus and must have an interface card. Some SoundBlaster cards were manufactured with a port to connect to the CD-ROM drive with this interface.
FreeBSD supports this interface with "matcd" driver. Linux supports these drives via the sbcd, sbpcd or pcd drivers.
External links
Page written by Theo Markettos, explaining the interface
Panasonic |
https://en.wikipedia.org/wiki/Multimedia%20Messaging%20Service | Multimedia Messaging Service (MMS) is a standard way to send messages that include multimedia content to and from a mobile phone over a cellular network. Users and providers may refer to such a message as a PXT, a picture message, or a multimedia message. The MMS standard extends the core SMS (Short Message Service) capability, allowing the exchange of text messages greater than 160 characters in length. Unlike text-only SMS, MMS can deliver a variety of media, including up to forty seconds of video, one image, a slideshow of multiple images, or audio.
The most common use involves sending photographs from camera-equipped handsets. Media companies have utilized MMS on a commercial basis as a method of delivering news and entertainment content, and retailers have deployed it as a tool for delivering scannable coupon codes, product images, videos, and other information.
The 3GPP and WAP groups fostered the development of the MMS standard, which is now continued by the Open Mobile Alliance (OMA).
Multimedia messaging service was built using the technology of SMS messaging, first developed in 1984 as a captive technology which enabled service providers to "collect a fee every time anyone snaps a photo."
The commercial introduction of MMS started in March 2002.
Between 2010 and 2013, MMS traffic in the U.S. increased by 70% from 57 billion to 96 billion messages sent. This is due in part to the wide adoption of smartphones.
Technical description
MMS messages are delivered in a different way from SMS. The first step is for the sending device to encode the multimedia content in a fashion similar to sending a MIME message (MIME content formats are defined in the MMS Message Encapsulation specification). The message is then forwarded to the carrier's MMS store and forward server, known as the MMSC (Multimedia Messaging Service Centre). If the receiver is on a carrier different from the sender, then the MMSC acts as a relay, and forwards the message to the MMSC of the recipient's carrier using the Internet.
Once the recipient's MMSC has received a message, it first determines whether the receiver's handset is "MMS capable" or not. If it supports the standards for receiving MMS, the content is extracted and sent to a temporary storage server with an HTTP front-end. An SMS "control message" containing the URL of the content is then sent to the recipient's handset to trigger the receiver's WAP browser to open and receive the content from the embedded URL. Several other messages are exchanged to indicate the status of the delivery attempt. Before delivering content, some MMSCs also include a conversion service that will attempt to modify the multimedia content into a format suitable for the receiver. This is known as "content adaptation".
If the receiver's handset is not MMS capable, the message is usually delivered to a web-based service from where the content can be viewed from a normal internet browser. The URL for the content is usually sent t |
https://en.wikipedia.org/wiki/Mikhail%20Botvinnik | Mikhail Moiseyevich Botvinnik ( – May 5, 1995) was a Soviet and Russian chess grandmaster. The sixth World Chess Champion, he also worked as an electrical engineer and computer scientist and was a pioneer in computer chess.
Botvinnik was the first world-class player to develop within the Soviet Union. He also played a major role in the organization of chess, making a significant contribution to the design of the World Chess Championship system after World War II and becoming a leading member of the coaching system that enabled the Soviet Union to dominate top-class chess during that time. His pupils include World Champions Anatoly Karpov, Garry Kasparov and Vladimir Kramnik.
Early years
Botvinnik was born on August 17, 1911, in what was then Kuokkala, Vyborg Governorate, Grand Duchy of Finland, now the district of Repino in Saint Petersburg. His parents were Russian Jews; his father, Moisei Botvinnik (1878–1931), was a dental technician and his mother, Shifra (Serafima) Rabinovich (1876–1952), a dentist, which allowed the family to live outside the Pale of Settlement, to which most Jews in the Russian Empire were restricted at the time. As a result, Botvinnik grew up in Saint Petersburg's Nevsky Prospect. His father forbade speaking Yiddish at home, and Mikhail and his older brother Isaak "Issy" attended Soviet schools. Botvinnik later recounted, "I was asked once, “What do you consider yourself to be from the point of view of nationality?” My reply was, “Yes, my position is 'complicated'. I am a Jew by blood, a Russian by culture, Soviet by upbringing.”" On his religious views, he called himself an atheist.
In 1920, his mother became ill and his father left the family, but maintained contact with the children, even after his second marriage to a Russian woman. At about the same time, Botvinnik started reading newspapers, and became a committed communist.
In autumn 1923, at the age of twelve, Botvinnik was taught chess by a school friend of his older brother, using a home-made set, and instantly fell in love with the game. He finished in mid-table in the school championship, sought advice from another of his brother's friends, and concluded that for him it was better to think out "concrete concepts" and then derive general principles from these – and went on to beat his brother's friend quite easily. In winter 1924, Botvinnik won his school's championship, and exaggerated his age by three years in order to become a member of the Petrograd Chess Assembly – to which its president turned a blind eye. Botvinnik won his first two tournaments organized by the Assembly. Shortly afterwards, Nikolai Krylenko, a devoted chess player and leading member of the Soviet legal system who later organized Joseph Stalin's show trials, began building a huge nationwide chess organization, and the Assembly was replaced by a club in the city's Palace of Labour.
To test the strength of Soviet chess masters, Krylenko organized the Moscow 1925 chess tournament. On a |
https://en.wikipedia.org/wiki/Personalized%20marketing | Personalized marketing, also known as one-to-one marketing or individual marketing, is a marketing strategy by which companies leverage data analysis and digital technology to deliver individualized messages and product offerings to current or prospective customers. Advancements in data collection methods, analytics, digital electronics, and digital economics, have enabled marketers to deploy more effective real-time and prolonged customer experience personalization tactics.
Beginning in the early 1990s, web developers began tracking HTML calls that their websites were receiving from online visitors. In 2012, the Web Analytics Association (WAA) officially changed its name to the Digital Analytics Association (DAA) in order to accommodate new and developing data streams that exist in addition to the web.
Technology
Personalized marketing is dependent on many different types of technology for data collection, data classification, data analysis, data transfer, and data scalability. Technology enables marketing professionals to collect first-party data such as gender, age group, location, and income and connect them with third-party data such as click-through rates of online banner ads and social media participation.
Data Management Platforms: A data management platform (DMP) is a centralized computing system for collecting, integrating and managing large sets of structured and unstructured data from disparate sources. Personalized marketing enabled by DMPs, is sold to advertisers with the goal of having consumers receive relevant, timely, engaging, and personalized messaging and advertisements that resonate with their unique needs and wants. Growing number of DMP software options are available including Adobe Systems Audience Manager and Core Audience (Marketing Cloud) to Oracle-acquired BlueKai, Sitecore Experience Platform and X+1
Customer Relationship Management Platforms: Customer relationship management (CRM) is used by companies to manage and analyze customer interactions and data throughout the customer lifecycle to improve business relationships with customers, assist in customer retention and drive sales growth. CRM systems are designed to compile information on customers across different channels (points of contact between the customer and the company) which could include the company's website, live support, direct mail, marketing materials and social media. CRM systems can also give customer-facing staff detailed information on customers' personal information, purchase history, buying preferences and concerns. Most popular enterprise CRM applications are Salesforce.com, Microsoft Dynamics CRM, NetSuite, and Oracle Eloqua.
Beacon Technology: Beacon technology works on Bluetooth low energy (BLE) which is used by a low frequency chip that is found in devices like mobile phones. These chips communicate with multiple Beacon devices to form a network and are used by marketers to better personalize the messaging and mobile ads based on the |
https://en.wikipedia.org/wiki/Mass%20customization | Mass customization makes use of flexible computer-aided systems to produce custom products. Such systems combine the low unit costs of mass production processes with the flexibility of individual customization.
Mass customization is the new frontier in business for both manufacturing and service industries. At its core, is a tremendous increase in variety and customization without a corresponding increase in costs. At its limit, it is the mass production of individually customized goods and services. At its best, it provides strategic advantage and economic value.
Product design strategy
Mass customization is a product design strategies and is currently used with both Delayed differentiation and modular design to enhance the value delivered to customers.
Mass customization is the method of "effectively postponing the task of differentiating a product for a specific customer until the latest possible point in the supply network".
Market research
Kamis, Koufaris and Stern (2008) conducted experiments to test the impacts of mass customization when postponed to the stage of retail, online shopping. They found that users perceive greater usefulness and enjoyment with a mass customization interface vs. a more typical shopping interface, particularly in a task of moderate complexity.
Engineering
From collaborative engineering perspective, mass customization can be viewed as collaborative efforts between customers and manufacturers, who have different sets of priorities and need to jointly search for solutions that best match customers' individual specific needs with manufacturers' customization capabilities.
History
The concept of mass customization is attributed to Stan Davis in Future Perfect, and was defined by as "producing goods and services to meet individual customers' needs with near mass production efficiency". concurred, calling it "a strategy that creates value by some form of company-customer interaction at the fabrication and assembly stage of the operations level to create customized products with production cost and monetary price similar to those of mass-produced products". Similarly, highlights that mass customization involves balancing operational drivers by defining it as "the capability to manufacture a relatively high volume of product options for a relatively large market (or collection of niche markets) that demands customization, without tradeoffs in cost, delivery and quality".
Implementation
Many implementations of mass customization are operational today, such as software-based product configurators that make it possible to add and/or change functionalities of a core product or to build fully custom enclosures from scratch. This degree of mass customization, however, has only seen limited adoption. If an enterprise's marketing department offers individual products (atomic market fragmentation), it doesn't often mean that a product is produced individually, but rather that similar variants of the same mass-produced it |
https://en.wikipedia.org/wiki/Traffic%20shaping | Traffic shaping is a bandwidth management technique used on computer networks which delays some or all datagrams to bring them into compliance with a desired traffic profile. Traffic shaping is used to optimize or guarantee performance, improve latency, or increase usable bandwidth for some kinds of packets by delaying other kinds. It is often confused with traffic policing, the distinct but related practice of packet dropping and packet marking.
The most common type of traffic shaping is application-based traffic shaping. In application-based traffic shaping, fingerprinting tools are first used to identify applications of interest, which are then subject to shaping policies. Some controversial cases of application-based traffic shaping include bandwidth throttling of peer-to-peer file sharing traffic. Many application protocols use encryption to circumvent application-based traffic shaping.
Another type of traffic shaping is route-based traffic shaping. Route-based traffic shaping is conducted based on previous-hop or next-hop information.
Functionality
If a link becomes utilized to the point where there is a significant level of congestion, latency can rise substantially. Traffic shaping can be used to prevent this from occurring and keep latency in check. Traffic shaping provides a means to control the volume of traffic being sent into a network in a specified period (bandwidth throttling), or the maximum rate at which the traffic is sent (rate limiting), or more complex criteria such as generic cell rate algorithm. This control can be accomplished in many ways and for many reasons; however traffic shaping is always achieved by delaying packets.
Traffic shaping is commonly applied at the network edges to control traffic entering the network, but can also be applied by the traffic source (for example, computer or network card) or by an element in the network.
Uses
Traffic shaping is sometimes applied by traffic sources to ensure the traffic they send complies with a contract which may be enforced in the network by traffic policing.
Shaping is widely used for teletraffic engineering, and appears in domestic ISPs' networks as one of several Internet Traffic Management Practices (ITMPs). Some ISPs may use traffic shaping to limit resources consumed by peer-to-peer file-sharing networks, such as BitTorrent.
Data centers use traffic shaping to maintain service level agreements for the variety of applications and the many tenants hosted as they all share the same physical network.
Audio Video Bridging includes an integral traffic-shaping provision defined in IEEE 802.1Qav.
Nodes in an IP network which buffer packets before sending on a link which is at capacity produce an unintended traffic shaping effect. This can appear across, for example, a low bandwidth link, a particularly expensive WAN link or satellite hop.
Implementation
A traffic shaper works by delaying metered traffic such that each packet complies with the relevant traffic c |
https://en.wikipedia.org/wiki/PMS%20%28disambiguation%29 | Premenstrual syndrome (PMS) is a collection of physical, psychological and emotional symptoms related to a woman's menstrual cycle.
PMS may also refer to:
Computers
Process management system, a system for business process management
Philip's Music Scribe, music scorewriter software
Pop'n Music Script, a computer file format for rhythm action games
Project management software
Property management system, software for hotel management
Pavement management#Pavement management systems, software for maintaining a road network
Personalization management system, software for managing the personalization of online user experiences
Nationality and politics
Partido Mexicano Socialista, a socialist political party in Mexico
Presidential Management Staff (Philippines), a government agency
Prime Ministers, see List of current prime ministers
Prime Minister's Spokesman, UK civil service post
Science and medicine
PMS1, a human protein involved in nucleotide mismatch repair
Medical practice management software, dealing with the management of a medical practice
Pectoralis minor syndrome
Postmarketing surveillance, monitoring of a pharmaceutical drug or device
Pre-main-sequence star, a star that has not yet reached the main sequence
Phelan-McDermid Syndrome, a rare genetic condition that causes developmental and speech delays, behavioral problems and a weakened ability to feel pain or sweat
Other uses
PMS Clan, an all-female gaming clan
Pantone Matching System, a proprietary color space
Piedmontese language (ISO 639-3 language code), a language used in northwest Italy.
Pleasanton Unified School District#Pleasanton Middle School, California, USA
Pontifical Mission Societies, a group of Catholic missionary societies
Portsmouth & Southsea railway station (National Rail station code), Hampshire, England
Pretty Mean Sisters, a 1990s stable in the World Wrestling Federation
Preventive maintenance schedule, a schedule for preventive maintenance |
https://en.wikipedia.org/wiki/Starfleet%20Command | Starfleet Command may refer to:
Video games
Star Trek: Starfleet Command, a computer game based on the table-top wargame Star Fleet Battles
Star Trek: Starfleet Command II: Empires at War, the sequel to Starfleet Command and second in the series of real-time space combat games
Star Trek: Starfleet Command: Orion Pirates, a stand-alone expansion for the computer game Star Trek: Starfleet Command II: Empires at War
Star Trek: Starfleet Command III, a Star Trek video game published in 2002
Other
Starfleet Command, the headquarters of, the fictional Star Trek exploration agency |
https://en.wikipedia.org/wiki/Transposition%20table | A transposition table is a cache of previously seen positions, and associated evaluations, in a game tree generated by a computer game playing program. If a position recurs via a different sequence of moves, the value of the position is retrieved from the table, avoiding re-searching the game tree below that position. Transposition tables are primarily useful in perfect-information games (where the entire state of the game is known to all players at all times). The usage of transposition tables is essentially memoization applied to the tree search and is a form of dynamic programming.
Transposition tables are typically implemented as hash tables encoding the current board position as the hash index. The number of possible positions that may occur in a game tree is an exponential function of depth of search, and can be thousands to millions or even much greater. Transposition tables may therefore consume most of available system memory and are usually most of the memory footprint of game playing programs.
Functionality
Game-playing programs work by analyzing millions of positions that could arise in the next few moves of the game. Typically, these programs employ strategies resembling depth-first search, which means that they do not keep track of all the positions analyzed so far. In many games, it is possible to reach a given position in more than one way. These are called transpositions. In chess, for example, the sequence of moves 1. d4 Nf6 2. c4 g6 (see algebraic chess notation) has 4 possible transpositions, since either player may swap their move order. In general, after n moves, an upper limit on the possible transpositions is (n!)2. Although many of these are illegal move sequences, it is still likely that the program will end up analyzing the same position several times.
To avoid this problem, transposition tables are used. Such a table is a hash table of each of the positions analyzed so far up to a certain depth. On encountering a new position, the program checks the table to see whether the position has already been analyzed; this can be done quickly, in amortized constant time. If so, the table contains the value that was previously assigned to this position; this value is used directly. If not, the value is computed, and the new position is entered into the hash table.
The number of positions searched by a computer often greatly exceeds the memory constraints of the system it runs on; thus not all positions can be stored. When the table fills up, less-used positions are removed to make room for new ones; this makes the transposition table a kind of cache.
The computation saved by a transposition table lookup is not just the evaluation of a single position. Instead, the evaluation of an entire subtree is avoided. Thus, transposition table entries for nodes at a shallower depth in the game tree are more valuable (since the size of the subtree rooted at such a node is larger) and are therefore given more importance when the t |
https://en.wikipedia.org/wiki/Optimal%20substructure | In computer science, a problem is said to have optimal substructure if an optimal solution can be constructed from optimal solutions of its subproblems. This property is used to determine the usefulness of greedy algorithms for a problem.
Typically, a greedy algorithm is used to solve a problem with optimal substructure if it can be proven by induction that this is optimal at each step. Otherwise, provided the problem exhibits overlapping subproblems as well, divide-and-conquer methods or dynamic programming may be used. If there are no appropriate greedy algorithms and the problem fails to exhibit overlapping subproblems, often a lengthy but straightforward search of the solution space is the best alternative.
In the application of dynamic programming to mathematical optimization, Richard Bellman's Principle of Optimality is based on the idea that in order to solve a dynamic optimization problem from some starting period t to some ending period T, one implicitly has to solve subproblems starting from later dates s, where t<s<T. This is an example of optimal substructure. The Principle of Optimality is used to derive the Bellman equation, which shows how the value of the problem starting from t is related to the value of the problem starting from s.
Example
Consider finding a shortest path for traveling between two cities by car, as illustrated in Figure 1. Such an example is likely to exhibit optimal substructure. That is, if the shortest route from Seattle to Los Angeles passes through Portland and then Sacramento, then the shortest route from Portland to Los Angeles must pass through Sacramento too. That is, the problem of how to get from Portland to Los Angeles is nested inside the problem of how to get from Seattle to Los Angeles. (The wavy lines in the graph represent solutions to the subproblems.)
As an example of a problem that is unlikely to exhibit optimal substructure, consider the problem of finding the cheapest airline ticket from Buenos Aires to Moscow. Even if that ticket involves stops in Miami and then London, we can't conclude that the cheapest ticket from Miami to Moscow stops in London, because the price at which an airline sells a multi-flight trip is usually not the sum of the prices at which it would sell the individual flights in the trip.
Definition
A slightly more formal definition of optimal substructure can be given. Let a "problem" be a collection of "alternatives", and let each alternative have an associated cost, c(a). The task is to find a set of alternatives that minimizes c(a). Suppose that the alternatives can be partitioned into subsets, i.e. each alternative belongs to only one subset. Suppose each subset has its own cost function. The minima of each of these cost functions can be found, as can the minima of the global cost function, restricted to the same subsets. If these minima match for each subset, then it's almost obvious that a global minimum can be picked not out of the full set of altern |
https://en.wikipedia.org/wiki/Spectral%20method | Spectral methods are a class of techniques used in applied mathematics and scientific computing to numerically solve certain differential equations. The idea is to write the solution of the differential equation as a sum of certain "basis functions" (for example, as a Fourier series which is a sum of sinusoids) and then to choose the coefficients in the sum in order to satisfy the differential equation as well as possible.
Spectral methods and finite element methods are closely related and built on the same ideas; the main difference between them is that spectral methods use basis functions that are generally nonzero over the whole domain, while finite element methods use basis functions that are nonzero only on small subdomains (compact support). Consequently, spectral methods connect variables globally while finite elements do so locally. Partially for this reason, spectral methods have excellent error properties, with the so-called "exponential convergence" being the fastest possible, when the solution is smooth. However, there are no known three-dimensional single domain spectral shock capturing results (shock waves are not smooth). In the finite element community, a method where the degree of the elements is very high or increases as the grid parameter h increases is sometimes called a spectral element method.
Spectral methods can be used to solve differential equations (PDEs, ODEs, eigenvalue, etc) and optimization problems. When applying spectral methods to time-dependent PDEs, the solution is typically written as a sum of basis functions with time-dependent coefficients; substituting this in the PDE yields a system of ODEs in the coefficients which can be solved using any numerical method for ODEs. Eigenvalue problems for ODEs are similarly converted to matrix eigenvalue problems .
Spectral methods were developed in a long series of papers by Steven Orszag starting in 1969 including, but not limited to, Fourier series methods for periodic geometry problems, polynomial spectral methods for finite and unbounded geometry problems, pseudospectral methods for highly nonlinear problems, and spectral iteration methods for fast solution of steady-state problems. The implementation of the spectral method is normally accomplished either with collocation or a Galerkin or a Tau approach . For very small problems, the spectral method is unique in that solutions may be written out symbolically, yielding a practical alternative to series solutions for differential equations.
Spectral methods can be computationally less expensive and easier to implement than finite element methods; they shine best when high accuracy is sought in simple domains with smooth solutions. However, because of their global nature, the matrices associated with step computation are dense and computational efficiency will quickly suffer when there are many degrees of freedom (with some exceptions, for example if matrix applications can be written as Fourier transforms). For lar |
https://en.wikipedia.org/wiki/Tarjan%27s%20off-line%20lowest%20common%20ancestors%20algorithm | In computer science, Tarjan's off-line lowest common ancestors algorithm is an algorithm for computing lowest common ancestors for pairs of nodes in a tree, based on the union-find data structure. The lowest common ancestor of two nodes d and e in a rooted tree T is the node g that is an ancestor of both d and e and that has the greatest depth in T. It is named after Robert Tarjan, who discovered the technique in 1979. Tarjan's algorithm is an offline algorithm; that is, unlike other lowest common ancestor algorithms, it requires that all pairs of nodes for which the lowest common ancestor is desired must be specified in advance. The simplest version of the algorithm uses the union-find data structure, which unlike other lowest common ancestor data structures can take more than constant time per operation when the number of pairs of nodes is similar in magnitude to the number of nodes. A later refinement by speeds the algorithm up to linear time.
Pseudocode
The pseudocode below determines the lowest common ancestor of each pair in P, given the root r of a tree in which the children of node n are in the set n.children. For this offline algorithm, the set P must be specified in advance. It uses the MakeSet, Find, and Union functions of a disjoint-set forest. MakeSet(u) removes u to a singleton set, Find(u) returns the standard representative of the set containing u, and Union(u,v) merges the set containing u with the set containing v.
TarjanOLCA(r) is first called on the root r.
function TarjanOLCA(u) is
MakeSet(u)
u.ancestor := u
for each v in u.children do
TarjanOLCA(v)
Union(u, v)
Find(u).ancestor := u
u.color := black
for each v such that {u, v} in P do
if v.color == black then
print "Tarjan's Lowest Common Ancestor of " + u +
" and " + v + " is " + Find(v).ancestor + "."
Each node is initially white, and is colored black after it and all its children have been visited.
For each node pair {u,v} to be investigated:
When v is already black (viz. when v comes before u in a post-order traversal of the tree): After u is colored black, the lowest common ancestor of this pair is available as Find(v).ancestor, but only while the LCA of u and v is not colored black.
Otherwise: Once v is colored black, the LCA will be available as Find(u).ancestor, while the LCA is not colored black.
For reference, here are optimized versions of MakeSet, Find, and Union for a disjoint-set forest:
function MakeSet(x) is
x.parent := x
x.rank := 1
function Union(x, y) is
xRoot := Find(x)
yRoot := Find(y)
if xRoot.rank > yRoot.rank then
yRoot.parent := xRoot
else if xRoot.rank < yRoot.rank then
xRoot.parent := yRoot
else if xRoot.rank == yRoot.rank then
yRoot.parent := xRoot
xRoot.rank := xRoot.rank + 1
function Find(x) is
if x.parent != x then
x.parent := Find(x.parent)
|
https://en.wikipedia.org/wiki/Uname | uname (short for unix name) is a computer program in Unix and Unix-like computer operating systems that prints the name, version and other details about the current machine and the operating system running on it.
History
The uname system call and command appeared for the first time in PWB/UNIX. Both are specified by POSIX. The GNU version of uname is included in the "sh-utils" or "coreutils" packages. uname itself is not available as a standalone program. The version of uname bundled in GNU coreutils was written by David MacKenzie. The command is available as a separate package for Microsoft Windows as part of the GnuWin32 project and the UnxUtils collection of native Win32 ports of common GNU Unix-like utilities.
Related and similar commands
Some Unix variants, such as AT&T UNIX System V Release 3.0, include the related setname program, used to change the values that uname reports.
The ver command found in operating systems such as DOS, OS/2 and Microsoft Windows is similar to the uname command.
The bash shell provides the special variables OSTYPE and HOSTTYPE whose values are similar to those of uname -o and uname -m respectively.
Examples
On a system running Darwin, the output from running uname with the -a command-line argument might look like the text below:
$ uname -a
Darwin Roadrunner.local 10.3.0 Darwin Kernel Version 10.3.0: Fri Feb 26 11:58:09 PST 2010; root:xnu-1504.3.12~1/RELEASE_I386 i386
The following table contains examples from various versions of uname on various platforms.
See also
List of Unix commands
lsb_release
ver (command)
Footnotes
External links
Unix SUS2008 utilities
IBM i Qshell commands |
https://en.wikipedia.org/wiki/Macintosh%20II%20family | The Macintosh II is a family of personal computers that was designed, manufactured and sold by Apple Computer, Inc. from 1987 to 1993. The Macintosh II was the initial model, representing the high-end of the Macintosh line for the time. Over the course of the next six years, seven more models were produced, culminating with the short-lived Macintosh IIvi and Macintosh IIvx models. Apple retired the Macintosh II name when it moved to Motorola 68040 processors; the Centris and Quadra names were used instead.
Features
Unlike prior Macintosh models, which are "all-in-one" designs, the Macintosh II models are "modular" systems which do not include built-in monitors and are expandable. Beginning with the Macintosh II and culminating in the Macintosh IIfx, the Macintosh II family was Apple's high-end line from 1987 until the introduction of the Motorola 68040-based Macintosh Quadra computers in 1991.
Expansion was provided by way of NuBus, which become the standard expansion bus for the entire Macintosh line for almost a decade. The Macintosh II was the first to officially support color displays, and the first (apart from the Macintosh XL) to support a screen resolution larger than 512x384.
The Macintosh II is also the first to use a Motorola 68000 series processor other than the Motorola 68000. Except for the original Macintosh II which launched the line with a Motorola 68020 clocked at 16 MHz, they exclusively used the Motorola 68030 microprocessor, even after the Motorola 68040 was introduced. Apple would eventually adopt the '040 with the introduction of the Quadra 700 and 900, positioning these models as high-end workstation-class machines for graphics and scientific computing, while positioning the Macintosh II family as a mainstream desktop computer.
Legacy
During the Macintosh II series' lifespan, they rose to become among the most powerful personal computers available. While the Macintosh II series itself was replaced by the Macintosh Centris and Quadra, the Macintosh LC and Performa families continued to use the II's 68030 technology long after the 68040 was introduced and the PowerBook continued to use the '030 into the Power Macintosh era.
Models
Macintosh II series memory map
Timeline
See also
List of Mac models grouped by CPU type
References
Mac II Series Index, Low End Mac
Discontinued Apple Inc. products
Products and services discontinued in 1993 |
https://en.wikipedia.org/wiki/Network%20interface%20controller | A network interface controller (NIC, also known as a network interface card, network adapter, LAN adapter or physical network interface, and by similar terms) is a computer hardware component that connects a computer to a computer network.
Early network interface controllers were commonly implemented on expansion cards that plugged into a computer bus. The low cost and ubiquity of the Ethernet standard means that most newer computers have a network interface built into the motherboard, or is contained into a USB-connected dongle.
Modern network interface controllers offer advanced features such as interrupt and DMA interfaces to the host processors, support for multiple receive and transmit queues, partitioning into multiple logical interfaces, and on-controller network traffic processing such as the TCP offload engine.
Purpose
The network controller implements the electronic circuitry required to communicate using a specific physical layer and data link layer standard such as Ethernet or Wi-Fi. This provides a base for a full network protocol stack, allowing communication among computers on the same local area network (LAN) and large-scale network communications through routable protocols, such as Internet Protocol (IP).
The NIC allows computers to communicate over a computer network, either by using cables or wirelessly. The NIC is both a physical layer and data link layer device, as it provides physical access to a networking medium and, for IEEE 802 and similar networks, provides a low-level addressing system through the use of MAC addresses that are uniquely assigned to network interfaces.
Implementation
Network controllers were originally implemented as expansion cards that plugged into a computer bus. The low cost and ubiquity of the Ethernet standard means that most new computers have a network interface controller built into the motherboard. Newer server motherboards may have multiple network interfaces built-in. The Ethernet capabilities are either integrated into the motherboard chipset or implemented via a low-cost dedicated Ethernet chip. A separate network card is typically no longer required unless additional independent network connections are needed or some non-Ethernet type of network is used. A general trend in computer hardware is towards integrating the various components of systems on a chip, and this is also applied to network interface cards.
An Ethernet network controller typically has an 8P8C socket where the network cable is connected. Older NICs also supplied BNC, or AUI connections. Ethernet network controllers typically support 10 Mbit/s Ethernet, 100 Mbit/s Ethernet, and 1000 Mbit/s Ethernet varieties. Such controllers are designated as 10/100/1000, meaning that they can support data rates of 10, 100 or 1000 Mbit/s. 10 Gigabit Ethernet NICs are also available, and, , are beginning to be available on computer motherboards.
Modular designs like SFP and SFP+ are highly popular, especially for fiber-optic comm |
https://en.wikipedia.org/wiki/Coroutine | Coroutines are computer program components that allow execution to be suspended and resumed, generalizing subroutines for cooperative multitasking. Coroutines are well-suited for implementing familiar program components such as cooperative tasks, exceptions, event loops, iterators, infinite lists and pipes.
They have been described as "functions whose execution you can pause".
Melvin Conway coined the term coroutine in 1958 when he applied it to the construction of an assembly program. The first published explanation of the coroutine appeared later, in 1963.
Definition and Types
There is no single precise definition of coroutine. In 1980 Christopher D. Marlin summarized two widely-acknowledged fundamental characteristics of a coroutine:
the values of data local to a coroutine persist between successive calls;
the execution of a coroutine is suspended as control leaves it, only to carry on where it left off when control re-enters the coroutine at some later stage.
Besides that, a coroutine implementation has 3 features:
the control-transfer mechanism. Asymmetric coroutines usually provide keywords like yield and resume. Programmers cannot freely choose which frame to yield to. The runtime only yields to the nearest caller of the current coroutine. On the other hand, in symmetric coroutine, programmers must specify a yield destination.
whether coroutines are provided in the language as first-class objects, which can be freely manipulated by the programmer, or as constrained constructs;
whether a coroutine is able to suspend its execution from within nested function calls. Such a coroutine is stackful. One to the contrary is called stackless coroutine, where unless marked as coroutine, a regular function can't use keyword yield.
Revisiting Coroutines published in 2009 proposed term Full Coroutine to denote one that supports first-class coroutine and is stackful. Full Coroutines deserve their own name in that they have the same expressive power as one-shot continuations and delimited continuations. Full coroutines are either symmetric or asymmetric. Importantly, whether a coroutine is symmetric or asymmetric has no bearing on how expressive it can be as they are equally as expressive, though full coroutines are more expressive than non-full coroutines. While their expressive power is the same, asymmetrical coroutines more closely resemble routine based control structures in the sense that control is always passed back to the invoker, which programmers may find more familiar.
Comparison with
Subroutines
Subroutines are special cases of coroutines. When subroutines are invoked, execution begins at the start, and once a subroutine exits, it is finished; an instance of a subroutine only returns once, and does not hold state between invocations. By contrast, coroutines can exit by calling other coroutines, which may later return to the point where they were invoked in the original coroutine; from the coroutine's point of view, it is not e |
https://en.wikipedia.org/wiki/D%20%28programming%20language%29 | D, also known as dlang, is a multi-paradigm system programming language created by Walter Bright at Digital Mars and released in 2001. Andrei Alexandrescu joined the design and development effort in 2007. Though it originated as a re-engineering of C++, D is a profoundly different language —features of D can be considered streamlined and expanded-upon ideas from C++, however D also draws inspiration from other high-level programming languages, notably Java, Python, Ruby, C#, and Eiffel.
D combines the performance and safety of compiled languages with the expressive power of modern dynamic and functional programming languages. Idiomatic D code is commonly as fast as equivalent C++ code, while also being shorter. The language as a whole is not memory-safe but includes optional attributes designed to guarantee memory safety of either subsets of or the whole program.
Type inference, automatic memory management and syntactic sugar for common types allow faster development, while bounds checking and design by contract find bugs earlier at runtime, and a concurrency-aware type system catches bugs at compile time.
Features
D was designed with lessons learned from practical C++ usage, rather than from a purely theoretical perspective. Although the language uses many C and C++ concepts, it also discards some, or uses different approaches (and syntax) to achieve some goals. As such, it is not source compatible (nor does it aim to be) with C and C++ source code in general (some simpler code bases from these languages might by luck work with D, or require some porting). D has, however, been constrained in its design by the rule that any code that was legal in both C and D should behave in the same way.
D gained some features before C++, such as closures, anonymous functions, compile-time function execution, ranges, built-in container iteration concepts and type inference. D adds to the functionality of C++ by also implementing design by contract, unit testing, true modules, garbage collection, first class arrays, associative arrays, dynamic arrays, array slicing, nested functions, lazy evaluation, scoped (deferred) code execution, and a re-engineered template syntax. C++ multiple inheritance was replaced by Java-style single inheritance with interfaces and mixins. On the other hand, D's declaration, statement and expression syntax closely matches that of C++.
D retains C++'s ability to perform low-level programming including inline assembler, which typifies the differences between D and application languages like Java and C#. Inline assembler lets programmers enter machine-specific assembly code within standard D code, a method used by system programmers to access the low-level features of the processor needed to run programs that interface directly with the underlying hardware, such as operating systems and device drivers, as well as writing high-performance code (i.e. using vector extensions, SIMD) that is hard to generate by the compiler automaticall |
https://en.wikipedia.org/wiki/Unix%20security | Unix security refers to the means of securing a Unix or Unix-like operating system. A secure environment is achieved not only by the design concepts of these operating systems, but also through vigilant user and administrative practices.
Design concepts
Permissions
A core security feature in these systems is the file system permissions. All files in a typical Unix filesystem have permissions set enabling different access to a file.
Permissions on a file are commonly set using the chmod command and seen through the ls command. For example:
-r-xr-xr-x 1 root wheel 745720 Sep 8 2002 /bin/sh
Unix permissions permit different users access to a file. Different user groups have different permissions on a file.
More advanced Unix filesystems include the Access Control List concept which allows permissions to be granted to multiple users or groups. An Access Control List may be used to grant permission to additional individual users or groups. For example:
/pvr [u::rwx,g::r-x,o::r-x/u::rwx,u:sue:rwx,g::r-x,m::rwx,o::r-x]
In this example, which is from the command on the Linux operating system, the user sue is granted write permission to the /pvr directory.
User groups
Users under Unix style operating systems often belong to managed groups with specific access permissions. This enables users to be grouped by the level of access they have to this system. Many Unix implementations add an additional layer of security by requiring that a user be a member of the wheel user privileges group in order to access the su command.
Root access
Most Unix and Unix-like systems have an account or group which enables a user to exact complete control over the system, often known as a root account. If access to this account is gained by an unwanted user, this results in a complete breach of the system. A root account however is necessary for administrative purposes, and for the above security reasons the root account is seldom used for day to day purposes (the sudo program is more commonly used), so usage of the root account can be more closely monitored.
Root access "as it should be" can be visualised by those familiar with the Superman stories using the following analogy:
Using a root account is rather like being Superman; an administrator's regular user is more like Clark Kent. Clark Kent becomes Superman for only as long as necessary, in order to save people. He then reverts to his "disguise". Root access should be used in the same fashion. The Clark Kent disguise doesn't really restrict him though, as he is still able to use his super powers. This is analogous to using the sudo program.
User and administrative techniques
Unix has many tools that can improve security if used properly by users and administrators.
Passwords
Selecting a strong password and guarding it properly are probably the most important things a user can do to improve Unix security.
In Unix systems, the essential information about users is stored under the file /etc/passwdThis f |
https://en.wikipedia.org/wiki/Direct%20address | Direct address may refer to:
Vocative expression, a term or phrase used to directly address an individual
The direct addressing mode in computer programming
Breaking the fourth wall in theatre |
https://en.wikipedia.org/wiki/Gtk-gnutella | gtk-gnutella is a peer-to-peer file sharing application which runs on the gnutella network. gtk-gnutella uses the GTK+ toolkit for its graphical user interface. Released under the GNU General Public License, gtk-gnutella is free software.
History
Initially gtk-gnutella was written to look like the original Nullsoft Gnutella client. The original author Yann Grossel stopped working on the client in early 2001. After a while Raphael Manfredi took over as the main software architect, and the client has been in active development ever since. Versions released after July 2002 do not look like the original Nullsoft client.
Features
gtk-gnutella is programmed in C with an emphasis on efficiency and portability without being minimalistic but rather head-on with most of the modern features of the gnutella network. Therefore, it requires fewer resources (such as CPU and/or RAM) than the major gnutella clients. It can also be used as headless gnutella client not requiring GTK+ at all.
gtk-gnutella has a filtering engine that can reduce the amount of spam and other irrelevant results. gtk-gnutella supports a large range of the features of modern gnutella clients. gtk-gnutella was the first gnutella client to support IPv6 and encryption using TLS. It can handle and export magnet links. It has strong internationalization features, supporting English, German, Greek, French, Hungarian, Spanish, Japanese, Norwegian, Dutch and Chinese. gtk-gnutella also has support to prevent spamming and other hostile peer activity.
Several software distributions provide pre-compiled packages, but they are usually outdated as many distributions version freeze old stable releases. The gnutella network benefits from running the latest version obtainable as peer and hostile IP address lists change rapidly, making building the latest SVN snapshot the best option. There are also pre-compiled packages for many Linux distributions available online. Persons concerned about security might wish to compile their own. The gtk-gnutella sources use dist as build and configuration system instead of Autoconf. Most users are only familiar with the configure scripts generated by the latter. Another hazard for novices is configuring NAT devices to enable full network connectivity for gtk-gnutella. gtk-gnutella, like any gnutella client, is still usable behind a firewall or a router, but with some reduced functionality, if it cannot receive incoming TCP connections or UDP packets. In an attempt to mitigate the issue for newcomers, gtk-gnutalla implements the UPnP and NAT-PMP client protocols.
gtk-gnutella supports features for downloading larger files (videos, programs, and disk images). Version 0.96.4 supports Tiger tree hash serving and versions after 0.96.5 support tiger tree hashes for uploads and downloads. Tiger tree hashing and other gtk-gnutella features make file transfers as efficient as BitTorrent. Specifically, gtk-gnutella supports partial file sharing, remote queueing and |
https://en.wikipedia.org/wiki/Singular%20%28software%29 | Singular (typeset Singular) is a computer algebra system for polynomial computations with special emphasis on the needs of commutative and non-commutative algebra, algebraic geometry, and singularity theory. Singular has been released under the terms of GNU General Public License. Problems in non-commutative algebra can be tackled with the Singular offspring Plural. Singular is developed under the direction of Wolfram Decker, Gert-Martin Greuel, Gerhard Pfister, and Hans Schönemann, who head Singular's core development team within the Department of Mathematics of the Technische Universität Kaiserslautern.
In the DFG Priority Program 1489, interfaces to GAP, Polymake and Gfan are being developed in order to cover recently established areas of mathematics involving convex and algebraic geometry, such as toric and tropical geometry.
See also
Comparison of computer algebra systems
References
Further reading
External links
Online Manual – PLURAL
Computer algebra system software for Linux
Computer algebra system software for macOS
Computer algebra system software for Windows
Free computer algebra systems |
https://en.wikipedia.org/wiki/Contention%20free%20pollable | Contention-free pollable (CF-Pollable) is a state of operation for wireless networking nodes. The condition is saying that the node is able to use the Point Coordination Function, as opposed to the Distributed Coordination Function, within a wireless LAN.
A device that is able to use point coordination function is one that is able to participate in a method to provide limited Quality of service (for time sensitive data) within the network.
See also
Contention (telecommunications)
References
Wireless networking |
https://en.wikipedia.org/wiki/ICS | ICS may refer to:
Computing
Image Cytometry Standard, a digital multidimensional image file format used in life sciences microscopy
Industrial control system, computer systems and networks used to control industrial plants and infrastructures
Information and computer science, the combined field of informatics and computing
Internet chess server, an external server that provides the facility to play, discuss, and view chess over the Internet
Internet Connection Sharing, a feature in Microsoft operating systems since the advent of Windows 98 Second Edition
.ics, a filename extension for iCalendar files
Android Ice Cream Sandwich, the codename for version 4.0 of the Android operating system
Education
Donald Bren School of Information and Computer Sciences, Irvine, California, United States
Graduate School of International Corporate Strategy, Tokyo, Japan
Indian Central School, Singapore
Institute for Christian Studies, Toronto, Ontario
Institute of Classical Studies, University of London, UK
Institute of Cornish Studies, in Falmouth, UK
Inter-Community School Zürich, Switzerland
Intermountain Christian School, Utah, United States
International Christian School (Hong Kong)
International Community School (Kirkland, Washington)
International Community School (Singapore)
International Community School (Thailand)
International Community School (UK)
International Community School of Addis Ababa
International Correspondence Schools
Islesboro Central School
Entertainment
International Channel Shanghai, a foreign-language cable channel
Immigration And Customs Security, a fictional organization in the Canadian TV series The Border
Music
ICS Vortex, alias of Simen Hestnæs, Norwegian rock musician
Immersion Composition Society, a network of composers, based in the USA
Medicine
Inhaled corticosteroid, steroid hormones used to treat the nasal mucosa, sinuses, bronchi, and lungs
Intercostal space, the space between two ribs
Organizations
ICS Africa
Imperial Civil Service
Indian Civil Service
Indian National Congress (Socialist)
Institute of Chartered Shipbrokers
Institute for Computational Sustainability, a Cornell-based institute in the United States
International Chamber of Shipping
International Citizen Service, a UK volunteer organization
International Commission on Stratigraphy, the largest scientific body within the International Union of Geological Sciences
International Communist Seminar
International Continence Society, a multidisciplinary membership society for medical professionals concerned with incontinence
Irish Computer Society, the national body for Information and Communication Technology (ICT) Professionals in Ireland
Integrated care system, a component of the National Health Service (England)
Technology
Ganz CSMG, also known as Ganz ICS, a Hungarian tram type
In Channel Select, a technology improving programme reception in FM tuners
Industrial control system
International Classification for St |
https://en.wikipedia.org/wiki/Adjacency%20matrix | In graph theory and computer science, an adjacency matrix is a square matrix used to represent a finite graph. The elements of the matrix indicate whether pairs of vertices are adjacent or not in the graph.
In the special case of a finite simple graph, the adjacency matrix is a (0,1)-matrix with zeros on its diagonal. If the graph is undirected (i.e. all of its edges are bidirectional), the adjacency matrix is symmetric.
The relationship between a graph and the eigenvalues and eigenvectors of its adjacency matrix is studied in spectral graph theory.
The adjacency matrix of a graph should be distinguished from its incidence matrix, a different matrix representation whose elements indicate whether vertex–edge pairs are incident or not, and its degree matrix, which contains information about the degree of each vertex.
Definition
For a simple graph with vertex set , the adjacency matrix is a square matrix such that its element is one when there is an edge from vertex to vertex , and zero when there is no edge. The diagonal elements of the matrix are all zero, since edges from a vertex to itself (loops) are not allowed in simple graphs. It is also sometimes useful in algebraic graph theory to replace the nonzero elements with algebraic variables. The same concept can be extended to multigraphs and graphs with loops by storing the number of edges between each two vertices in the corresponding matrix element, and by allowing nonzero diagonal elements. Loops may be counted either once (as a single edge) or twice (as two vertex-edge incidences), as long as a consistent convention is followed. Undirected graphs often use the latter convention of counting loops twice, whereas directed graphs typically use the former convention.
Of a bipartite graph
The adjacency matrix of a bipartite graph whose two parts have and vertices can be written in the form
where is an matrix, and and represent the and zero matrices. In this case, the smaller matrix uniquely represents the graph, and the remaining parts of can be discarded as redundant. is sometimes called the biadjacency matrix.
Formally, let be a bipartite graph with parts , and edges . The biadjacency matrix is the 0–1 matrix in which if and only if .
If is a bipartite multigraph or weighted graph, then the elements are taken to be the number of edges between the vertices or the weight of the edge , respectively.
Variations
An -adjacency matrix of a simple graph has if is an edge, if it is not, and on the diagonal. The Seidel adjacency matrix is a -adjacency matrix. This matrix is used in studying strongly regular graphs and two-graphs.
The distance matrix has in position the distance between vertices and . The distance is the length of a shortest path connecting the vertices. Unless lengths of edges are explicitly provided, the length of a path is the number of edges in it. The distance matrix resembles a high power of the adjacency matrix, but instead of telling only |
https://en.wikipedia.org/wiki/SOCKS | SOCKS is an Internet protocol that exchanges network packets between a client and server through a proxy server. SOCKS5 optionally provides authentication so only authorized users may access a server. Practically, a SOCKS server proxies TCP connections to an arbitrary IP address, and provides a means for UDP packets to be forwarded.
SOCKS performs at Layer 5 of the OSI model (the session layer, an intermediate layer between the presentation layer and the transport layer). A SOCKS server accepts incoming client connection on TCP port 1080, as defined in .
History
The protocol was originally developed/designed by David Koblas, a system administrator of MIPS Computer Systems. After MIPS was taken over by Silicon Graphics in 1992, Koblas presented a paper on SOCKS at that year's Usenix Security Symposium, making SOCKS publicly available. The protocol was extended to version 4 by Ying-Da Lee of NEC.
The SOCKS reference architecture and client are owned by Permeo Technologies, a spin-off from NEC. (Blue Coat Systems bought out Permeo Technologies, and were in turn acquired by Symantec.)
The SOCKS5 protocol was originally a security protocol that made firewalls and other security products easier to administer. It was approved by the IETF in 1996 as (authored by: M. Leech, M. Ganis, Y. Lee, R. Kuris, D. Koblas, and L. Jones). The protocol was developed in collaboration with Aventail Corporation, which markets the technology outside of Asia.
Acronym
SOCKS is sometimes defined as an acronym for "socket secure" from at least 2001, although it was not originally defined as such in the SOCKS Protocol Version 5 RFC in 1996 or the UNIX Security Symposium III paper in 1992 but simply referred to a specific proxy protocol designed to facilitate communication between clients and servers through a firewall.
Usage
SOCKS is a de facto standard for circuit-level gateways (level 5 gateways).
The circuit/session level nature of SOCKS make it a versatile tool in forwarding any TCP (or UDP since SOCKS5) traffic, creating an interface for all types of routing tools. It can be used as:
A circumvention tool, allowing traffic to bypass Internet filtering to access content otherwise blocked, e.g., by governments, workplaces, schools, and country-specific web services. Since SOCKS is very detectable, a common approach is to present a SOCKS interface for more sophisticated protocols:
The Tor onion proxy software presents a SOCKS interface to its clients.
Providing similar functionality to a virtual private network, allowing connections to be forwarded to a server's "local" network:
Some SSH suites, such as OpenSSH, support dynamic port forwarding that allows the user to create a local SOCKS proxy. This can free the user from the limitations of connecting only to a predefined remote port and server.
Protocol
SOCKS4
A typical SOCKS4 connection request looks like this:
VER SOCKS version number, 0x04 for this version
CMD command code:
0x01 = establish a TCP/IP stre |
https://en.wikipedia.org/wiki/Water%20integrator | The Water Integrator ( Gidravlicheskiy integrator) was an early analog computer built in the Soviet Union in 1936 by Vladimir Sergeevich Lukyanov. It functioned by careful manipulation of water through a room full of interconnected pipes and pumps. The water level in various chambers (with precision to fractions of a millimeter) represented stored numbers, and the rate of flow between them represented mathematical operations. This machine was capable of solving inhomogeneous differential equations.
The first versions of Lukyanov's integrators were rather experimental, made of tin and glass tubes, and each integrator could be used to solve only one problem. In the 1930s it was the only computer in the Soviet Union for solving partial differential equations.
In 1941, Lukyanov created a hydraulic integrator of modular design, which made it possible to assemble a machine for solving various problems. Two-dimensional and three-dimensional hydraulic integrators were designed.
In 1949–1955, an integrator in the form of standard unified units was developed at the NIISCHETMASH Institute. In 1955, the Ryazan plant of calculating and analytical machines began the serial production of integrators with the factory brand name “IGL” (russian: Интегратор Гидравлический Лукьянова - integrator of the Lukyanov hydraulic system). Integrators were widely distributed, delivered to Czechoslovakia, Poland, Bulgaria and China.
A water integrator was used in the design of the Karakum Canal in the 1940s, and the construction of the Baikal–Amur Mainline in the 1970s. Water analog computers were used in the Soviet Union until the 1980s for large-scale modelling. They were used in geology, mine construction, metallurgy, rocket production and other fields.
Currently, two hydraulic integrators are kept in the Polytechnic Museum in Moscow.
See also
History of computing hardware
MONIAC Computer
Fluidics
References
Further reading
Collection of Water Integrator Patents
Technical Reports involving use/design of Water Integrators USACE, etc.
External links
MIT water computer
Translated article from Russian Magazin "Science and Life" about water integrators in the Soviet Union
Translation of an archived article from O. V. Solovyov on the former webpage of the Polytechnic Museum in Moscow
Hydraulic Analog Computer Technical Reports. A "collection of technical reports from the USACE (US Army Corps of Engineers) that was written by the Civil and Sanitary Engineering Department at MIT as part of a contract to create a Hydraulic Computer for solving diffusion-type Partial Differential Equations" from 1953
One-of-a-kind computers
Early computers
Analog computers
Soviet inventions |
https://en.wikipedia.org/wiki/Lock%20%28computer%20science%29 | In computer science, a lock or mutex (from mutual exclusion) is a synchronization primitive: a mechanism that enforces limits on access to a resource when there are many threads of execution. A lock is designed to enforce a mutual exclusion concurrency control policy, and with a variety of possible methods there exists multiple unique implementations for different applications.
Types
Generally, locks are advisory locks, where each thread cooperates by acquiring the lock before accessing the corresponding data. Some systems also implement mandatory locks, where attempting unauthorized access to a locked resource will force an exception in the entity attempting to make the access.
The simplest type of lock is a binary semaphore. It provides exclusive access to the locked data. Other schemes also provide shared access for reading data. Other widely implemented access modes are exclusive, intend-to-exclude and intend-to-upgrade.
Another way to classify locks is by what happens when the lock strategy prevents the progress of a thread. Most locking designs block the execution of the thread requesting the lock until it is allowed to access the locked resource. With a spinlock, the thread simply waits ("spins") until the lock becomes available. This is efficient if threads are blocked for a short time, because it avoids the overhead of operating system process re-scheduling. It is inefficient if the lock is held for a long time, or if the progress of the thread that is holding the lock depends on preemption of the locked thread.
Locks typically require hardware support for efficient implementation. This support usually takes the form of one or more atomic instructions such as "test-and-set", "fetch-and-add" or "compare-and-swap". These instructions allow a single process to test if the lock is free, and if free, acquire the lock in a single atomic operation.
Uniprocessor architectures have the option of using uninterruptible sequences of instructions—using special instructions or instruction prefixes to disable interrupts temporarily—but this technique does not work for multiprocessor shared-memory machines. Proper support for locks in a multiprocessor environment can require quite complex hardware or software support, with substantial synchronization issues.
The reason an atomic operation is required is because of concurrency, where more than one task executes the same logic. For example, consider the following C code:
if (lock == 0) {
// lock free, set it
lock = myPID;
}
The above example does not guarantee that the task has the lock, since more than one task can be testing the lock at the same time. Since both tasks will detect that the lock is free, both tasks will attempt to set the lock, not knowing that the other task is also setting the lock. Dekker's or Peterson's algorithm are possible substitutes if atomic locking operations are not available.
Careless use of locks can result in deadlock or livelock. A number of strategies can |
https://en.wikipedia.org/wiki/Two-phase%20locking | In databases and transaction processing, two-phase locking (2PL) is a concurrency control method that guarantees serializability.
It is also the name of the resulting set of database transaction schedules (histories). The protocol uses locks, applied by a transaction to data, which may block (interpreted as signals to stop) other transactions from accessing the same data during the transaction's life.
By the 2PL protocol, locks are applied and removed in two phases:
Expanding phase: locks are acquired and no locks are released.
Shrinking phase: locks are released and no locks are acquired.
Two types of locks are used by the basic protocol: Shared and Exclusive locks. Refinements of the basic protocol may use more lock types. Using locks that block processes, 2PL may be subject to deadlocks that result from the mutual blocking of two or more transactions.
Data-access locks
A lock is a system object associated with a shared resource such as a data item of an elementary type, a row in a database, or a page of memory. In a database, a lock on a database object (a data-access lock) may need to be acquired by a transaction before accessing the object. Correct use of locks prevents undesired, incorrect or inconsistent operations on shared resources by other concurrent transactions. When a database object with an existing lock acquired by one transaction needs to be accessed by another transaction, the existing lock for the object and the type of the intended access are checked by the system. If the existing lock type does not allow this specific attempted concurrent access type, the transaction attempting access is blocked (according to a predefined agreement/scheme). In practice, a lock on an object does not directly block a transaction's operation upon the object, but rather blocks that transaction from acquiring another lock on the same object, needed to be held/owned by the transaction before performing this operation. Thus, with a locking mechanism, needed operation blocking is controlled by a proper lock blocking scheme, which indicates which lock type blocks which lock type.
Two major types of locks are used:
Write-lock (exclusive lock) is associated with a database object by a transaction (Terminology: "the transaction locks the object," or "acquires lock for it") before writing (inserting/modifying/deleting) this object.
Read-lock (shared lock) is associated with a database object by a transaction before reading (retrieving the state of) this object.
The common interactions between these lock types are defined by blocking behavior as follows:
An existing write-lock on a database object blocks an intended write upon the same object (already requested/issued) by another transaction by blocking a respective write-lock from being acquired by the other transaction. The second write-lock will be acquired and the requested write of the object will take place (materialize) after the existing write-lock is released.
A write-lock blocks an inte |
https://en.wikipedia.org/wiki/Spinlock | In software engineering, a spinlock is a lock that causes a thread trying to acquire it to simply wait in a loop ("spin") while repeatedly checking whether the lock is available. Since the thread remains active but is not performing a useful task, the use of such a lock is a kind of busy waiting. Once acquired, spinlocks will usually be held until they are explicitly released, although in some implementations they may be automatically released if the thread being waited on (the one that holds the lock) blocks or "goes to sleep".
Because they avoid overhead from operating system process rescheduling or context switching, spinlocks are efficient if threads are likely to be blocked for only short periods. For this reason, operating-system kernels often use spinlocks. However, spinlocks become wasteful if held for longer durations, as they may prevent other threads from running and require rescheduling. The longer a thread holds a lock, the greater the risk that the thread will be interrupted by the OS scheduler while holding the lock. If this happens, other threads will be left "spinning" (repeatedly trying to acquire the lock), while the thread holding the lock is not making progress towards releasing it. The result is an indefinite postponement until the thread holding the lock can finish and release it. This is especially true on a single-processor system, where each waiting thread of the same priority is likely to waste its quantum (allocated time where a thread can run) spinning until the thread that holds the lock is finally finished.
Implementing spinlocks correctly is challenging because programmers must take into account the possibility of simultaneous access to the lock, which could cause race conditions. Generally, such an implementation is possible only with special assembly language instructions, such as atomic (i.e. un-interruptible) test-and-set operations and cannot be easily implemented in programming languages not supporting truly atomic operations. On architectures without such operations, or if high-level language implementation is required, a non-atomic locking algorithm may be used, e.g. Peterson's algorithm. However, such an implementation may require more memory than a spinlock, be slower to allow progress after unlocking, and may not be implementable in a high-level language if out-of-order execution is allowed.
Example implementation
The following example uses x86 assembly language to implement a spinlock. It will work on any Intel 80386 compatible processor.
; Intel syntax
locked: ; The lock variable. 1 = locked, 0 = unlocked.
dd 0
spin_lock:
mov eax, 1 ; Set the EAX register to 1.
xchg eax, [locked] ; Atomically swap the EAX register with
; the lock variable.
; This will always store 1 to the lock, leaving
; the previous value in the EAX register.
test eax, eax |
https://en.wikipedia.org/wiki/Higher-order%20function | In mathematics and computer science, a higher-order function (HOF) is a function that does at least one of the following:
takes one or more functions as arguments (i.e. a procedural parameter, which is a parameter of a procedure that is itself a procedure),
returns a function as its result.
All other functions are first-order functions. In mathematics higher-order functions are also termed operators or functionals. The differential operator in calculus is a common example, since it maps a function to its derivative, also a function. Higher-order functions should not be confused with other uses of the word "functor" throughout mathematics, see Functor (disambiguation).
In the untyped lambda calculus, all functions are higher-order; in a typed lambda calculus, from which most functional programming languages are derived, higher-order functions that take one function as argument are values with types of the form .
General examples
map function, found in many functional programming languages, is one example of a higher-order function. It takes as arguments a function f and a collection of elements, and as the result, returns a new collection with f applied to each element from the collection.
Sorting functions, which take a comparison function as a parameter, allowing the programmer to separate the sorting algorithm from the comparisons of the items being sorted. The C standard function qsort is an example of this.
filter
fold
apply
Function composition
Integration
Callback
Tree traversal
Montague grammar, a semantic theory of natural language, uses higher-order functions
Support in programming languages
Direct support
The examples are not intended to compare and contrast programming languages, but to serve as examples of higher-order function syntax
In the following examples, the higher-order function takes a function, and applies the function to some value twice. If has to be applied several times for the same it preferably should return a function rather than a value. This is in line with the "don't repeat yourself" principle.
APL
twice←{⍺⍺ ⍺⍺ ⍵}
plusthree←{⍵+3}
g←{plusthree twice ⍵}
g 7
13
Or in a tacit manner:
twice←⍣2
plusthree←+∘3
g←plusthree twice
g 7
13
C++
Using in C++11:
#include <iostream>
#include <functional>
auto twice = [](const std::function<int(int)>& f)
{
return [f](int x) {
return f(f(x));
};
};
auto plus_three = [](int i)
{
return i + 3;
};
int main()
{
auto g = twice(plus_three);
std::cout << g(7) << '\n'; // 13
}
Or, with generic lambdas provided by C++14:
#include <iostream>
auto twice = [](const auto& f)
{
return [f](int x) {
return f(f(x));
};
};
auto plus_three = [](int i)
{
return i + 3;
};
int main()
{
auto g = twice(plus_three);
std::cout << g(7) << '\n'; // 13
}
C#
Using just delegates:
using System;
public class Program
{
public static void Main(string |
https://en.wikipedia.org/wiki/SQLite | SQLite (, ) is a database engine written in the C programming language. It is not a standalone app; rather, it is a library that software developers embed in their apps. As such, it belongs to the family of embedded databases. It is the most widely deployed database engine, as it is used by several of the top web browsers, operating systems, mobile phones, and other embedded systems.
Many programming languages have bindings to the SQLite library. It generally follows PostgreSQL syntax, but does not enforce type checking by default. This means that one can, for example, insert a string into a column defined as an integer.
History
D. Richard Hipp designed SQLite in the spring of 2000 while working for General Dynamics on contract with the United States Navy. Hipp was designing software used for a damage-control system aboard guided-missile destroyers, which originally used HP-UX with an IBM Informix database back-end. SQLite began as a Tcl extension.
In August 2000, version 1.0 of SQLite was released, with storage based on gdbm (GNU Database Manager). In September 2001, SQLite 2.0 replaced gdbm with a custom B-tree implementation, adding transaction capability. In June 2004, SQLite 3.0 added internationalization, manifest typing, and other major improvements, partially funded by America Online. In 2011, Hipp announced his plans to add a NoSQL interface to SQLite, as well as announcing UnQL, a functional superset of SQL designed for document-oriented databases. In 2018, SQLite adopted a Code of Conduct based on the Rule of Saint Benedict which caused some controversy and was later renamed as a Code of Ethics.
SQLite is one of four formats recommended for long-term storage of datasets approved for use by the Library of Congress.
Design
SQLite was designed to allow the program to be operated without installing a database management system or requiring a database administrator. Unlike client–server database management systems, the SQLite engine has no standalone processes with which the application program communicates. Instead, a linker integrates the SQLite library statically or dynamically into an application program which uses SQLite's functionality through simple function calls, reducing latency in database operations; for simple queries with little concurrency, SQLite performance profits from avoiding the overhead of inter-process communication.
Due to the serverless design, SQLite applications require less configuration than client–server databases. SQLite is called zero-conf because it does not require service management (such as startup scripts) or access control based on GRANT and passwords. Access control is handled by means of file-system permissions given to the database file itself. Databases in client–server systems use file-system permissions that give access to the database files only to the daemon process, which handles its locks internally, allowing concurrent writes from several processes.
SQLite stores the whole database |
https://en.wikipedia.org/wiki/Write-ahead%20logging | In computer science, write-ahead logging (WAL) is a family of techniques for providing atomicity and durability (two of the ACID properties) in database systems.
It can be seen as an implementation of the "Event Sourcing" architecture, in which the state of a system is the result of the evolution of incoming events from an initial state.
A write ahead log is an append-only auxiliary disk-resident structure used for crash and transaction recovery. The changes are first recorded in the log, which must be written to stable storage, before the changes are written to the database.
The main functionality of a write-ahead log can be summarized as:
Allow the page cache to buffer updates to disk-resident pages while ensuring durability semantics in the larger context of a database system.
Persist all operations on disk until the cached copies of pages affected by these operations are synchronized on disk. Every operation that modifies the database state has to be logged on disk before the contents on the associated pages can be modified
Allow lost in-memory changes to be reconstructed from the operation log in case of a crash.
In a system using WAL, all modifications are written to a log before they are applied. Usually both redo and undo information is stored in the log.
The purpose of this can be illustrated by an example. Imagine a program that is in the middle of performing some operation when the machine it is running on loses power. Upon restart, that program might need to know whether the operation it was performing succeeded, succeeded partially, or failed. If a write-ahead log is used, the program can check this log and compare what it was supposed to be doing when it unexpectedly lost power to what was actually done. On the basis of this comparison, the program could decide to undo what it had started, complete what it had started, or keep things as they are.
After a certain amount of operations, the program should perform a checkpoint, writing all the changes specified in the WAL to the database and clearing the log.
WAL allows updates of a database to be done in-place. Another way to implement atomic updates is with shadow paging, which is not in-place. The main advantage of doing updates in-place is that it reduces the need to modify indexes and block lists.
ARIES is a popular algorithm in the WAL family.
Modern file systems typically use a variant of WAL for at least file system metadata; this is called journaling.
References
Database algorithms |
https://en.wikipedia.org/wiki/GEnie | GEnie (General Electric Network for Information Exchange) was an online service created by a General Electric business, GEIS (now GXS), that ran from 1985 through the end of 1999. In 1994, GEnie claimed around 350,000 users. Peak simultaneous usage was around 10,000 users. It was one of the pioneering services in the field, though eventually replaced by the World Wide Web and graphics-based services, most notably AOL.
Early history
GEnie was founded by Bill Louden on October 1, 1985 and was launched as an ASCII text-based service by GE's Information Services division in October 1985, and received attention as the first serious commercial competition to CompuServe. Louden was originally CompuServe's product manager for Computing, Community (forums), Games, eCommerce, and email product lines. Louden purchased DECWAR source code and had MegaWars developed, one of the earliest multi-player online games (or MMOG), in 1985.
The service was run by General Electric Information Services (GEIS, now GXS) based in Rockville, Maryland. GEIS served a diverse set of large-scale, international, commercial network-based custom application needs, including banking, electronic data interchange and e-mail services to companies worldwide, but was able to run GEnie on their many GE Mark III time-sharing mainframe computers that otherwise would have been underutilized after normal U.S. business hours. This orientation was part of GEnie's downfall. Although it became very popular and a national force in the on-line marketplace, GEnie was not allowed to grow. GEIS executives steadfastly refused to view the service as anything but "fill in" load and would not expand the network by a single phone line, let alone expand mainframe capacity, to accommodate GEnie's growing user base. (Later, however, GE did consent to make the service available through the SprintNet time-sharing network, which had its own dial-up points of presence; an Internet-to-SprintNet gateway operated by Merit Network also made the text-based parts of the service available through telnet.)
The initial price for connection, at both 300 bits per second and the then-high-speed 1,200 bits per second, was $5–6 per hour during "non-prime-time" hours (evenings and weekends) and $36 an hour (to discourage daytime use) otherwise, later adjusted to $6 per hour and $18 per hour, respectively. A speed of 2,400 bit/s was also available at a premium. Later, GEnie developed the Star*Services package, soon renamed Genie*Basic after Prodigy threatened a trademark lawsuit over the use of the word "Star". It offered a set of "unlimited use" features for $4.95 per month. Other services cost extra, mirroring the tiered service model popular at the time.
GEnie's forums were called RoundTables (RTs), and each, as well as other internal services, had a page number associated with it, akin to a Web address today; typing "m 1335", for instance, would bring you to the GemStone III game page. The service included RTs, games, |
https://en.wikipedia.org/wiki/Message%20delivery%20agent | A message delivery agent (MDA), or mail delivery agent, is a computer software component that is responsible for the delivery of e-mail messages to a local recipient's mailbox. It is also called a local delivery agent (LDA).
Within the Internet mail architecture, local message delivery is achieved through a process of handling messages from the message transfer agent, and storing mail into the recipient's environment (typically a mailbox).
Implementation
Many mail handling software products bundle multiple message delivery agents with the message transfer agent component, providing for site customization of the specifics of mail delivery to a user.
Unix
On Unix-like systems, procmail and maildrop are the most popular MDAs. The Local Mail Transfer Protocol (LMTP) is a protocol that is frequently implemented by network-aware MDAs.
Invocation
The mail delivery agent is generally not started from the command line, but is usually invoked by mail delivery subsystems, such as a mail transport agent, or a mail retrieval agent.
List of MDA software for Unix-like platforms
Cyrus IMAP - A mail server suite that includes a mail delivery agent
dovecot - A mail server suite that includes a mail delivery agent
fetchmail - Primarily a Mail retrieval agent (MRA)
getmail - simpler, more secure, modern fetchmail alternative
fdm — modern replacement for both fetchmail and procmail from the author of tmux
maildrop or courier-maildrop - traditional procmail replacement, part of Courier Mail Server, but can also be used with other mail servers
procmail - old, but still used
bin/mail, the MDA part of Sendmail - Sendmail is one of the oldest email packages
Sieve mail filtering language - a standardised mail filtering language; also, a modern replacement for procmail from the GNU Mailutils package
See also
Message transfer agent (MTA)
Mail retrieval agent (MRA)
Message submission agent (MSA)
Message user agent (MUA) a.k.a. email client
E-mail agent (infrastructure) (MxA)
References |
https://en.wikipedia.org/wiki/The%20Young%20Doctors | The Young Doctors is an Australian early-evening soap opera originally broadcast on the Nine Network and produced by the Reg Grundy Organisation, it aired from Monday 8 November 1976 until Wednesday 30 March 1983. The series is primarily set in the fictional Albert Memorial Hospital, as well as the restaurant/nightclub Bunny's Place, and is fundamentally concerned with the romances and relations between younger members of the hospital staff, rather than typical medical issues and procedures.
The program was shown and exported internationally including throughout North America and Canada and Europe including the United Kingdom, the Netherlands, France and Spain.
Series history
Early years
The series produced by the Grundy Organisation was created and devised by Alan Coleman with Reg Watson acting as Executive Producer.
Watson had been the Producer of the British TV soap opera Crossroads from 1964 to 1973 and he moved back to Australia to help set up a new drama department within the Reg Grundy Organisation, which at the time, was better known for its game and quiz shows. With Coleman producing, as well as Watson's experience of making fast-turnaround, five-days a week serial drama, The Young Doctors became the third soap opera produced by the Reg Grundy Organisation following the Seven Network's serials Class of 74 / 75, and Until Tomorrow, which screened briefly in 1975.
The Young Doctors began in November 1976, a week earlier than another new soap opera on Network Nine, The Sullivans, which was produced by Crawford Productions. The Nine Network made it clear only one of the series would be commissioned beyond the initial 13-week production run (approximately 65 episodes).
The Sullivans, which had a three times greater budget, after the trial period emerged as the critical success, so The Young Doctors was cancelled.
Fans however lobbied the Nine Network, who then reversed their decision and by popular demand The Young Doctors continued in its daily 6.00 pm slot and had a successful run of six and a half years, making it one of Australia's longest running and popular serials of the time.
Later years
The Young Doctors long-serving cast members began to leave, so during the final season in 1982–83, many new characters were added in an attempt to modernise and refresh the long-running serial.
Producer and co-creator Alan Coleman also left in early 1982, and was replaced by Sue Masters twelve months before the series finished production in late November 1982. Masters went on to produce Grundy's replacement medical soap, Starting Out, for Nine, and then Grundy's stablemate, Prisoner, from 1983.
Several cast members after the series ended production went on to have leading roles in cult series Prisoner including Judy McBurney, Genevieve Lemon, Babs McMillan, Tottie Goldsmith and Peter Bensley.
The advent of one-day cricket led to the Nine Network moving the show around the schedules. The loss of several popular cast members also contributed |
https://en.wikipedia.org/wiki/Sheaf%20%28mathematics%29 | In mathematics, a sheaf (: sheaves) is a tool for systematically tracking data (such as sets, abelian groups, rings) attached to the open sets of a topological space and defined locally with regard to them. For example, for each open set, the data could be the ring of continuous functions defined on that open set. Such data is well behaved in that it can be restricted to smaller open sets, and also the data assigned to an open set is equivalent to all collections of compatible data assigned to collections of smaller open sets covering the original open set (intuitively, every piece of data is the sum of its parts).
The field of mathematics that studies sheaves is called sheaf theory.
Sheaves are understood conceptually as general and abstract objects. Their correct definition is rather technical. They are specifically defined as sheaves of sets or as sheaves of rings, for example, depending on the type of data assigned to the open sets.
There are also maps (or morphisms) from one sheaf to another; sheaves (of a specific type, such as sheaves of abelian groups) with their morphisms on a fixed topological space form a category. On the other hand, to each continuous map there is associated both a direct image functor, taking sheaves and their morphisms on the domain to sheaves and morphisms on the codomain, and an inverse image functor operating in the opposite direction. These functors, and certain variants of them, are essential parts of sheaf theory.
Due to their general nature and versatility, sheaves have several applications in topology and especially in algebraic and differential geometry. First, geometric structures such as that of a differentiable manifold or a scheme can be expressed in terms of a sheaf of rings on the space. In such contexts, several geometric constructions such as vector bundles or divisors are naturally specified in terms of sheaves. Second, sheaves provide the framework for a very general cohomology theory, which encompasses also the "usual" topological cohomology theories such as singular cohomology. Especially in algebraic geometry and the theory of complex manifolds, sheaf cohomology provides a powerful link between topological and geometric properties of spaces. Sheaves also provide the basis for the theory of D-modules, which provide applications to the theory of differential equations. In addition, generalisations of sheaves to more general settings than topological spaces, such as Grothendieck topology, have provided applications to mathematical logic and to number theory.
Definitions and examples
In many mathematical branches, several structures defined on a topological space (e.g., a differentiable manifold) can be naturally localised or restricted to open subsets : typical examples include continuous real-valued or complex-valued functions, -times differentiable (real-valued or complex-valued) functions, bounded real-valued functions, vector fields, and sections of any vector bundle on the space. The |
https://en.wikipedia.org/wiki/DSLAM | A digital subscriber line access multiplexer (DSLAM, often pronounced DEE-slam) is a network device, often located in telephone exchanges, that connects multiple customer digital subscriber line (DSL) interfaces to a high-speed digital communications channel using multiplexing techniques. Its cable internet (DOCSIS) counterpart is the cable modem termination system.
Path taken by data to DSLAM
Customer premises: DSL modem terminating the ADSL, SHDSL or VDSL circuit and providing a LAN or interface to a single computer or LAN segment.
Local loop: the telephone company wires from a customer to the telephone exchange or to a serving area interface, often called the "last mile" (LM).
Telephone exchange:
Main distribution frame (MDF): a wiring rack that connects outside subscriber lines with internal lines. It is used to connect public or private lines coming into the building to internal networks. At the telco, the MDF is generally in proximity to the cable vault and not far from the telephone switch.
xDSL filters: DSL filters are used in the telephone exchange to split voice from data signals. The voice signal can be routed to a plain old telephone service (POTS) provider, digital telephone exchange or left unused whilst the data signal is routed to the ISP DSLAM via the HDF (see next entry).
Handover distribution frame (HDF): a distribution frame that connects the last mile provider with the service provider's DSLAM
DSLAM: a device for DSL service. The DSLAM port where the subscriber local loop is connected converts analog electrical signals to data traffic (upstream traffic for data upload) and data traffic to analog electrical signals (downstream for data download).
Role of the DSLAM
The DSLAM equipment collects the data from its many modem ports and aggregates their voice and data traffic into one complex composite "signal" via multiplexing. Depending on its device architecture and setup, a DSLAM aggregates the DSL lines over its Asynchronous Transfer Mode (ATM), Frame Relay, and/or Internet Protocol network, i.e., an IP-DSLAM using Packet Transfer Mode - Transmission Convergence (PTM-TC) protocol(s) stack.
The aggregated traffic is then directed to a telco's backbone switch, via an access network (AN), also called a Network Service Provider (NSP), at up to 10 Gbit/s data rates.
The DSLAM acts like a network switch since its functionality is at Layer 2 of the OSI model. Therefore, it cannot re-route traffic between multiple IP networks, only between ISP devices and end-user connection points. The DSLAM traffic is switched to a Broadband Remote Access Server where the end-user traffic is then routed across the ISP network to the Internet. Customer-premises equipment that interfaces well with the DSLAM to which it is connected may take advantage of enhanced telephone voice and data line signaling features and the bandwidth monitoring and compensation capabilities it supports.
A DSLAM may or may not be located in the telephone exchang |
https://en.wikipedia.org/wiki/ARX%20%28operating%20system%29 | ARX was an unreleased Mach-like operating system written in Modula-2+ developed by Acorn Computers Ltd in the Acorn Research Centre (ARC) United Kingdom (UK) and later by Olivetti - which purchased Acorn - for Acorn's new Archimedes personal computers based on the ARM architecture reduced instruction set computer (RISC) central processing unit (CPUs).
Overview
According to the project Application Manager Richard Cownie, during the project, while Acorn was developing the kernel, it used the C and Acorn Modula Execution Library (CAMEL) in the Acorn Extended Modula-2 (AEM2) compiler (ported from Modula-2 ETH Zurich (ETH) using Econet hardware). Though never released externally, CAMEL was ported to use on Sun Microsystems Unix computers. In an effort to port Sun's workstations Sun NeWS to the Archimedes, David Chase developed a compiler based on AEM2 for the programming language Modula-3.
ARX was a preemptive multitasking, multithreading, multi-user operating system. Much of the OS ran in user mode and as a result suffered performance problems due to switches into kernel mode to perform mutexes, which led to the introduction of the SWP instruction to the instruction set of the ARMv2a version of the ARM processor. It had support of a file system for optical (write once read many (WORM)) disks and featured a window system, a window toolkit (and a direct manipulation user interface (UI) editor) and an Interscript-based text editor, for enriched documents written in Interpress (a HTML precursor). The OS had to be fitted in a 512 KB read-only memory (ROM) ROM image. This suggests that ARX had a microkernel-type design.
It was not finished in time to be used in the Acorn Archimedes range of computers, which shipped in 1987 with an operating system named Arthur, later renamed RISC OS, derived from the earlier Machine Operating System (MOS) from Acorn's earlier 8-bit BBC Micro range. Confusion persisted about the nature of ARX amongst the wider public and press, with some believing that ARX was Acorn's own Unix variant, with this view being refined in time to accommodate ARX as Acorn's own attempt to deliver a "UNIX look-alike" whose development had been abandoned in favour of a traditional Unix version for the Archimedes, which ultimately emerged as RISC iX.
The Acorn Research Centre was acquired by Olivetti.
See also
RISC iX
References
External links
ARX features
History of the addition of the SWP instruction to the ARM3 instruction set
Acorn Computers operating systems
ARM operating systems
Discontinued operating systems
Microkernel-based operating systems
Microkernels |
https://en.wikipedia.org/wiki/Chicago%20Enforcers | The Chicago Enforcers were an American football team of the XFL based at Soldier Field in Chicago, Illinois. The XFL was begun by Vince McMahon of the WWE and by NBC, a major television network in the United States. NBC dropped XFL broadcasts after the first season in 2001 due to dismal ratings, and the league was dissolved shortly thereafter.
The team name references mob enforcers, alluding to Chicago's history of mafia influence. The team's fight song would later become the entrance music for professional wrestler Brock Lesnar who had signed a contract with the WWE but was yet to debut.
The "Chicago Enforcers" name is used by the Chicago Police Department for their works team in the National Public Safety Football League.
2001 season
Originally, rumors swirled that former Chicago Bears defensive coordinator and Philadelphia Eagles head coach Buddy Ryan would be hired as the team's coach. Ultimately, Hall of Fame linebacker Dick Butkus was hired for the position. However, just before the season started, he resigned to take a position in the XFL office. He was replaced by Ron Meyer, a former NFL head coach from the 1980s who had not coached professional football since 1994 with the Las Vegas Posse.
Among their players was former NFL running back LeShon Johnson, who had played for the Green Bay Packers, Arizona Cardinals and the New York Giants. He was starting tailback for the Cardinals for most of 1996. He led the Enforcers with 6 rushing touchdowns, which was second in the league. They also had former NFL running back John Avery who played for the Miami Dolphins. Their wide receiver/kick returner Roell Preston (who previously played for the Atlanta Falcons, Green Bay Packers, Miami Dolphins, San Francisco 49ers, and Tennessee Titans) held the distinction of being the only former Pro Bowler (1998 as a Packer) to play in the XFL. The team's starting right guard, Bennie Anderson, went on to be a starter for the Baltimore Ravens and Buffalo Bills, and last played professional football in 2006 for the Miami Dolphins.
The Enforcers got off to a slow start, losing their first four games with Tim Lester; at the time, Lester was working as a math teacher and assistant football coach at Wheaton Warrenville South High School in the suburbs of Chicago and played for the Enforcers effectively as a semi-professional player. In week 5, the team replaced Lester with the former Notre Dame Quatrerback Kevin McDougal, cut Lester, and brought in Craig Whelihan (an established NFL backup who had been third string on the Memphis Maniax at the time) to serve as McDougal's backup. The team went 5–1 in the rest of the season (winning their last four in a row), coming from behind to make the XFL playoffs at 2nd place in the Eastern Division. In addition to their potent rushing attack led by league leading running back John Avery, they were also known for their hard hitting defense. They lost to eventual XFL champion Los Angeles Xtreme in the crossover semifinal |
https://en.wikipedia.org/wiki/Orlando%20Rage | The Orlando Rage was an American football team based in Orlando, Florida as part of the XFL, begun by Vince McMahon of the World Wrestling Federation and by NBC, a major television network in the United States.
History
The team's colors were scarlet, yellow, navy blue and white with jersey numbers in a unique jagged font. They played their home games at Orlando's Florida Citrus Bowl, which was configured so that the upper deck was closed off and all fans were seated in the lower bowl to give a better appearance for television (a move that was effective, as the Rage had one of the stronger fan bases in the league, with average attendance at over two-thirds of the lower bowl's capacity; the team sold out all 36,000 lower bowl seats for its home opener). The team's General Manager was Tom Veit a former Major League Soccer Vice-president and were coached by former Florida Gators head coach Galen Hall. They were in the XFL's Eastern Division with the NY/NJ Hitmen, Chicago Enforcers and Birmingham Thunderbolts.
The Rage were one of the two teams who opted not to don nicknames on the back of their jerseys. In the Rage's case, the decision was made by a majority vote of the players (despite the objections of starting quarterback Jeff Brohm, who openly embraced the XFL's approach to sports entertainment and wanted to wear "J Bro" on his jersey).
Jeff Brohm, at the time also under contract to the Cleveland Browns, was the quarterback of the Rage for most of the regular season, amassing a 6–0 record as starter during his first time at the helm. The team looked to be the league's powerhouse franchise under Brohm and was on pace for a perfect season (coincidentally, Orlando's next professional football team, the Florida Tuskers, would also win their first six games in a row before losing the seventh). He showed his toughness after he suffered an injury from a devastating hit by at the hands of Memphis Maniax defensive end Shante Carver in Week 5. Despite suffering a concussion in the hit and doctors' advice not to play, Brohm came back a week later against Las Vegas, giving a rousing speech stating that he was returning because it was the XFL and he still had a pulse. The following week he suffered a shoulder injury against the Los Angeles Xtreme and his season (and playing career) was done for good. It led to him being replaced by Brian Kuklick after six games. While Kuklick filled in the role of quarterback acceptably, the team lost a valuable leader on offense. The team went 2–2 in Kuklick's care; Kuklick, despite only starting four games, led the league in interceptions with 10.
The team finished their only regular season with an 8–2 record, the best in the league, but were upset in the first round of the playoffs by the 5–5 San Francisco Demons. Orlando had an early 16–0 advantage but allowed San Francisco to pull ahead and take a 26–16 lead by the fourth quarter. Using the XFL's newly introduced three-point conversion rule on a subsequent touchdo |
https://en.wikipedia.org/wiki/Shadow%20paging | In computer science, shadow paging is a technique for providing atomicity and durability (two of the ACID properties) in database systems. A page in this context refers to a unit of physical storage (probably on a hard disk), typically of the order of 1 to 64 KiB.
Shadow paging is a copy-on-write technique for avoiding in-place updates of pages. Instead, when a page is to be modified, a shadow page is allocated. Since the shadow page has no references (from other pages on disk), it can be modified liberally, without concern for consistency constraints, etc. When the page is ready to become durable, all pages that referred to the original are updated to refer to the new replacement page instead. Because the page is "activated" only when it is ready, it is atomic.
If the referring pages must also be updated via shadow paging, this procedure may recurse many times, becoming quite costly. One solution, employed by the Write Anywhere File Layout (WAFL) file system is to be lazy about making pages durable (i.e., write-behind caching). This increases performance significantly by avoiding many writes on hotspots high up in the referential hierarchy (e.g., a file system superblock) at the cost of high commit latency.
Write-ahead logging is a more popular solution that uses in-place updates.
Shadow paging is similar to the old master–new master batch processing technique used in mainframe database systems. In these systems, the output of each batch run (possibly a day's work) was written to two separate disks or other form of storage medium. One was kept for backup, and the other was used as the starting point for the next day's work.
Shadow paging is also similar to purely functional data structures, in that in-place updates are avoided.
References
Database algorithms
Computer file systems
fa:صفحه_بندی_سایه |
https://en.wikipedia.org/wiki/Women%20Thrive%20Worldwide | Women Thrive Alliance, formerly Women Thrive Worldwide and Women's Edge, is a global feminist advocacy network created in 1998 that advocates for gender equality. Working with the grassroots organizations in 53 countries.
Emily Bove is the Executive Director of Women Thrive Alliance.
Women Thrive Alliance's total support and revenue for 2017 were US$871,955.00.
In 2005, Amnesty International USA and Women Thrive Worldwide organized meetings with members of the United States Senate to work toward legislation to combat violence against women and girls around the world. These meetings led to the 2007 International Violence Against Women Act, which was introduced by Senators Joseph Biden and Richard Lugar.
Women Thrive Worldwide has lobbied and helped pass such legislation as the Access for Afghan Women Act, the Afghanistan Freedom Support Act, the GAINS for Women and Girls Act, the Trade Impact Review and the GROWTH Act.
Ritu Sharma Fox is co-founder and the president. USAID calls her "a leading voice on international women's issues and U.S. foreign policy."
According to USAID, "due in large part" to Women Thrive Worldwide, "the interests of poor women worldwide are now being incorporated into U.S. economic assistance and trade policies and, in some cases, into U.S. law itself.
Advocates in the United States Congress for Women Thrive Worldwide Carolyn Maloney, Patty Murray, Richard Durbin, Mary Landrieu, Barbara Mikulski, and Nita Lowey.
References
Women's political advocacy groups in the United States
Organizations established in 1998 |
https://en.wikipedia.org/wiki/Durability%20%28database%20systems%29 | In database systems, durability is the ACID property that guarantees that the effects of transactions that have been committed will survive permanently, even in case of failures, including incidents and catastrophic events. For example, if a flight booking reports that a seat has successfully been booked, then the seat will remain booked even if the system crashes.
Formally, a database system ensures the durability property if it tolerates three types of failures: transaction, system, and media failures. In particular, a transaction fails if its execution is interrupted before all its operations have been processed by the system. These kinds of interruptions can be originated at the transaction level by data-entry errors, operator cancellation, timeout, or application-specific errors, like withdrawing money from a bank account with insufficient funds. At the system level, a failure occurs if the contents of the volatile storage are lost, due, for instance, to system crashes, like out-of-memory events. At the media level, where media means a stable storage that withstands system failures, failures happen when the stable storage, or part of it, is lost. These cases are typically represented by disk failures.
Thus, to be durable, the database system should implement strategies and operations that guarantee that the effects of transactions that have been committed before the failure will survive the event (even by reconstruction), while the changes of incomplete transactions, which have not been committed yet at the time of failure, will be reverted and will not affect the state of the database system. These behaviours are proven to be correct when the execution of transactions has respectively the resilience and recoverability properties.
Mechanisms
In transaction-based systems, the mechanisms that assure durability are historically associated with the concept of reliability of systems, as proposed by Jim Gray in 1981. This concept includes durability, but it also relies on aspects of the atomicity and consistency properties. Specifically, a reliability mechanism requires primitives that explicitly state the beginning, the end, and the rollback of transactions, which are also implied for the other two aforementioned properties. In this article, only the mechanisms strictly related to durability have been considered. These mechanisms are divided into three levels: transaction, system, and media level. This can be seen as well for scenarios where failures could happen and that have to be considered in the design of database systems to address durability.
Transaction level
Durability against failures that occur at transaction level, such as canceled calls and inconsistent actions that may be blocked before committing by constraints and triggers, is guaranteed by the serializability property of the execution of transactions. The state generated by the effects of precedently committed transactions is available in main memory and, thus, is resilie |
https://en.wikipedia.org/wiki/Artificial%20Intelligence%20for%20Environment%20%26%20Sustainability | Artificial Intelligence for Environment & Sustainability (ARIES) is an international non-profit research project hosted by the Basque Centre for Climate Change (BC3) headquartered in Bilbao, Spain. It was created to integrate scientific computational models for environmental sustainability assessment and policy-making, through ecoinformatics.
Technology and applications
ARIES seeks to integrate scientific data and models that simulate environmental and socioeconomic systems to address linked scientific modelling problems, through semantics (computer science), FAIR data and models, and an open-source software infrastructure called Knowledge Laboratory (k.LAB) to semantically describe, code, and distribute data and models for end-users, modellers, and network administrators.
ARIES currently includes two web-based applications: the k.Explorer and the ARIES for SEEA Explorer. Released in Fall 2018, k.Explorer is an interface that allows non-technical users to run sophisticated models. The ARIES for SEEA Explorer was released in April 2021 by BC3 in collaboration with the Statistics Division of the United Nations Department of Economic and Social Affairs (UN DESA) and the United Nations Environment Programme (UNEP) for rapid, standardized and customizable natural capital accounting. Shortly following the adoption of the System of Integrated Environmental and Economic Accounting (SEEA) Ecosystem Accounting standard by United Nations in March 2021, the ARIES for SEEA Explorer was made available on the UN Global Platform in order to accelerate SEEA's implementation worldwide.
History and partners
The ARIES Project started in April 2007 at the Gund Institute for Ecological Economics of the University of Vermont, United States, sponsored by a $1M grant from the U.S. government's National Science Foundation. A prototype of the model building system was developed over the following year, and a functional prototype was made available online in 2012. Since 2010, the project has been based at BC3, where the technology has continued developing ever since. Since 2013, the ARIES team has held the International Spring University (ISU) on Ecosystem Services Modelling, an annual intensive modelling school for scientists and policy analysts working in the environmental sustainability field.
ARIES is led from a global hub at BC3 in collaboration with Ca' Foscari University of Venice, the Global Change Research Centre, HydroloGIS Environmental Engineering, IHCantabria, the Institute of Materials and Systems for Sustainability of Nagoya University, the Inter-American Development Bank (IDB), UN DESA, the University of Udine, and the United States Geological Survey (USGS).
References
External links
ARIES website
Environmental organisations based in Spain
Knowledge representation software |
https://en.wikipedia.org/wiki/Algorithms%20for%20Recovery%20and%20Isolation%20Exploiting%20Semantics | In computer science, Algorithms for Recovery and Isolation Exploiting Semantics, or ARIES is a recovery algorithm designed to work with a no-force, steal database approach; it is used by IBM Db2, Microsoft SQL Server and many other database systems. IBM Fellow Dr. C. Mohan is the primary inventor of the ARIES family of algorithms.
Three main principles lie behind ARIES
Write-ahead logging: Any change to an object is first recorded in the log, and the log must be written to stable storage before changes to the object are written to disk.
Repeating history during Redo: On restart after a crash, ARIES retraces the actions of a database before the crash and brings the system back to the exact state that it was in before the crash. Then it undoes the transactions still active at crash time.
Logging changes during Undo: Changes made to the database while undoing transactions are logged to ensure such an action isn't repeated in the event of repeated restarts.
Logging
The ARIES algorithm relies on logging of all database operations with ascending Sequence Numbers. Usually the resulting logfile is stored on so-called "stable storage", that is a storage medium that is assumed to survive crashes and hardware failures.
To gather the necessary information for the logs, two data structures have to be maintained: the dirty page table (DPT) and the transaction table (TT).
The dirty page table keeps record of all the pages that have been modified, and not yet written to disk, and the first Sequence Number that caused that page to become dirty. The transaction table contains all currently running transactions and the Sequence Number of the last log entry they created.
We create log records of the form (Sequence Number, Transaction ID, Page ID, Redo, Undo, Previous Sequence Number). The Redo and Undo fields keep information about the changes this log record saves and how to undo them. The Previous Sequence Number is a reference to the previous log record that was created for this transaction. In the case of an aborted transaction, it's possible to traverse the log file in reverse order using the Previous Sequence Numbers, undoing all actions taken within the specific transaction.
Every transaction implicitly begins with the first "Update" type of entry for the given Transaction ID, and is committed with "End Of Log" (EOL) entry for the transaction.
During a recovery, or while undoing the actions of an aborted transaction, a special kind of log record is written, the Compensation Log Record (CLR), to record that the action has already been undone. CLRs are of the form (Sequence Number, Transaction ID, Page ID, Redo, Previous Sequence Number, Next Undo Sequence Number). The Redo field contains application of Undo field of reverted action, and the Undo field is omitted because CLR is never reverted.
Recovery
The recovery works in three phases. The first phase, Analysis, computes all the necessary information from the logfile. The Redo phase restores |
https://en.wikipedia.org/wiki/Instruction-level%20parallelism | Instruction-level parallelism (ILP) is the parallel or simultaneous execution of a sequence of instructions in a computer program. More specifically ILP refers to the average number of instructions run per step of this parallel execution.
Discussion
ILP must not be confused with concurrency. In ILP there is a single specific thread of execution of a process. On the other hand, concurrency involves the assignment of multiple threads to a CPU's core in a strict alternation, or in true parallelism if there are enough CPU cores, ideally one core for each runnable thread.
There are two approaches to instruction-level parallelism: hardware and software.
Hardware level works upon dynamic parallelism, whereas the software level works on static parallelism. Dynamic parallelism means the processor decides at run time which instructions to execute in parallel, whereas static parallelism means the compiler decides which instructions to execute in parallel. The Pentium processor works on the dynamic sequence of parallel execution, but the Itanium processor works on the static level parallelism.
Consider the following program:
e = a + b
f = c + d
m = e * f
Operation 3 depends on the results of operations 1 and 2, so it cannot be calculated until both of them are completed. However, operations 1 and 2 do not depend on any other operation, so they can be calculated simultaneously. If we assume that each operation can be completed in one unit of time then these three instructions can be completed in a total of two units of time, giving an ILP of 3/2.
A goal of compiler and processor designers is to identify and take advantage of as much ILP as possible. Ordinary programs are typically written under a sequential execution model where instructions execute one after the other and in the order specified by the programmer. ILP allows the compiler and the processor to overlap the execution of multiple instructions or even to change the order in which instructions are executed.
How much ILP exists in programs is very application specific. In certain fields, such as graphics and scientific computing the amount can be very large. However, workloads such as cryptography may exhibit much less parallelism.
Micro-architectural techniques that are used to exploit ILP include:
Instruction pipelining where the execution of multiple instructions can be partially overlapped.
Superscalar execution, VLIW, and the closely related explicitly parallel instruction computing concepts, in which multiple execution units are used to execute multiple instructions in parallel.
Out-of-order execution where instructions execute in any order that does not violate data dependencies. Note that this technique is independent of both pipelining and superscalar execution. Current implementations of out-of-order execution dynamically (i.e., while the program is executing and without any help from the compiler) extract ILP from ordinary programs. An alternative is to extract this parallelis |
https://en.wikipedia.org/wiki/Transaction%20log | In the field of databases in computer science, a transaction log (also transaction journal, database log, binary log or audit trail) is a history of actions executed by a database management system used to guarantee ACID properties over crashes or hardware failures. Physically, a log is a file listing changes to the database, stored in a stable storage format.
If, after a start, the database is found in an inconsistent state or not been shut down properly, the database management system reviews the database logs for uncommitted transactions and rolls back the changes made by these transactions. Additionally, all transactions that are already committed but whose changes were not yet materialized in the database are re-applied. Both are done to ensure atomicity and durability of transactions.
This term is not to be confused with other, human-readable logs that a database management system usually provides.
In database management systems, a journal is the record of data altered by a given process.
Anatomy of a general database log
A database log record is made up of:
Log Sequence Number (LSN): A unique ID for a log record. With LSNs, logs can be recovered in constant time. Most LSNs are assigned in monotonically increasing order, which is useful in recovery algorithms, like ARIES.
Prev LSN: A link to their last log record. This implies database logs are constructed in linked list form.
Transaction ID number: A reference to the database transaction generating the log record.
Type: Describes the type of database log record.
Information about the actual changes that triggered the log record to be written.
Types of database log records
All log records include the general log attributes above, and also other attributes depending on their type (which is recorded in the Type attribute, as above).
Update Log Record notes an update (change) to the database. It includes this extra information:
PageID: A reference to the Page ID of the modified page.
Length and Offset: Length in bytes and offset of the page are usually included.
Before and After Images: Includes the value of the bytes of page before and after the page change. Some databases may have logs which include one or both images.
Compensation Log Record (CLR) notes the rollback of a particular change to the database. Each corresponds with exactly one other Update Log Record (although the corresponding update log record is not typically stored in the Compensation Log Record). It includes this extra information:
undoNextLSN: This field contains the LSN of the next log record that is to be undone for transaction that wrote the last Update Log.
Commit Record notes a decision to commit a transaction.
Abort Record notes a decision to abort and hence roll back a transaction.
Checkpoint Record notes that a checkpoint has been made. These are used to speed up recovery. They record information that eliminates the need to read a long way into the log's past. This varies according to checkpoint algorithm |
https://en.wikipedia.org/wiki/Elimination%20theory | In commutative algebra and algebraic geometry, elimination theory is the classical name for algorithmic approaches to eliminating some variables between polynomials of several variables, in order to solve systems of polynomial equations.
Classical elimination theory culminated with the work of Francis Macaulay on multivariate resultants, as described in the chapter on Elimination theory in the first editions (1930) of Bartel van der Waerden's Moderne Algebra. After that, elimination theory was ignored by most algebraic geometers for almost thirty years, until the introduction of new methods for solving polynomial equations, such as Gröbner bases, which were needed for computer algebra.
History and connection to modern theories
The field of elimination theory was motivated by the need of methods for solving systems of polynomial equations.
One of the first results was Bézout's theorem, which bounds the number of solutions (in the case of two polynomials in two variables at Bézout time).
Except for Bézout's theorem, the general approach was to eliminate variables for reducing the problem to a single equation in one variable.
The case of linear equations was completely solved by Gaussian elimination, where the older method of Cramer's rule does not proceed by elimination, and works only when the number of equations equals the number of variables. In the 19th century, this was extended to linear Diophantine equations and abelian group with Hermite normal form and Smith normal form.
Before the 20th century, different types of eliminants were introduced, including resultants, and various kinds of discriminants. In general, these eliminants are also invariant under various changes of variables, and are also fundamental in invariant theory.
All these concepts are effective, in the sense that their definitions include a method of computation. Around 1890, David Hilbert introduced non-effective methods, and this was seen as a revolution, which led most algebraic geometers of the first half of the 20th century to try to "eliminate elimination". Nevertheless Hilbert's Nullstellensatz, may be considered to belong to elimination theory, as it asserts that a system of polynomial equations does not have any solution if and only if one may eliminate all unknowns to obtain the constant equation 1 = 0.
Elimination theory culminated with the work of Leopold Kronecker, and finally Macaulay, who introduced multivariate resultants and U-resultants, providing complete elimination methods for systems of polynomial equations, which are described in the chapter on Elimination theory in the first editions (1930) of van der Waerden's Moderne Algebra.
Later, elimination theory was considered old-fashioned and removed from subsequent editions of Moderne Algebra. It was generally ignored until the introduction of computers, and more specifically of computer algebra, which again made relevant the design of efficient elimination algorithms, rather than merely existence |
https://en.wikipedia.org/wiki/Prediction | A prediction (Latin præ-, "before," and dicere, "to say"), or forecast, is a statement about a future event or data. They are often, but not always, based upon experience or knowledge. There is no universal agreement about the exact difference from "estimation"; different authors and disciplines ascribe different connotations.
Future events are necessarily uncertain, so guaranteed accurate information about the future is impossible. Prediction can be useful to assist in making plans about possible developments.
Opinion
In a non-statistical sense, the term "prediction" is often used to refer to an informed guess or opinion.
A prediction of this kind might be informed by a predicting person's abductive reasoning, inductive reasoning, deductive reasoning, and experience; and may be useful—if the predicting person is a knowledgeable person in the field.
The Delphi method is a technique for eliciting such expert-judgement-based predictions in a controlled way. This type of prediction might be perceived as consistent with statistical techniques in the sense that, at minimum, the "data" being used is the predicting expert's cognitive experiences forming an intuitive "probability curve."
Statistics
In statistics, prediction is a part of statistical inference. One particular approach to such inference is known as predictive inference, but the prediction can be undertaken within any of the several approaches to statistical inference. Indeed, one possible description of statistics is that it provides a means of transferring knowledge about a sample of a population to the whole population, and to other related populations, which is not necessarily the same as prediction over time. When information is transferred across time, often to specific points in time, the process is known as forecasting. Forecasting usually requires time series methods, while prediction is often performed on cross-sectional data.
Statistical techniques used for prediction include regression and its various sub-categories such as linear regression, generalized linear models (logistic regression, Poisson regression, Probit regression), etc. In case of forecasting, autoregressive moving average models and vector autoregression models can be utilized. When these and/or related, generalized set of regression or machine learning methods are deployed in commercial usage, the field is known as predictive analytics.
In many applications, such as time series analysis, it is possible to estimate the models that generate the observations. If models can be expressed as transfer functions or in terms of state-space parameters then smoothed, filtered and predicted data estimates can be calculated. If the underlying generating models are linear then a minimum-variance Kalman filter and a minimum-variance smoother may be used to recover data of interest from noisy measurements. These techniques rely on one-step-ahead predictors (which minimise the variance of the prediction error). When the g |
https://en.wikipedia.org/wiki/Predictor | Predictor may refer to:
Branch predictor, a part of many modern processors
Kerrison Predictor, a military fire-control computer
Predictor variable, also known as an independent variable
A type of railway level crossing, circuit that tries to achieve a constant warning time by predicting the speed of the approaching train
Something which makes a prediction
See also
Prediction (disambiguation)
Predict (disambiguation) |
https://en.wikipedia.org/wiki/Forecasting | Forecasting is the process of making predictions based on past and present data. Later these can be compared (resolved) against what happens. For example, a company might estimate their revenue in the next year, then compare it against the actual results creating a variance actual analysis. Prediction is a similar but more general term. Forecasting might refer to specific formal statistical methods employing time series, cross-sectional or longitudinal data, or alternatively to less formal judgmental methods or the process of prediction and resolution itself. Usage can vary between areas of application: for example, in hydrology the terms "forecast" and "forecasting" are sometimes reserved for estimates of values at certain specific future times, while the term "prediction" is used for more general estimates, such as the number of times floods will occur over a long period.
Risk and uncertainty are central to forecasting and prediction; it is generally considered a good practice to indicate the degree of uncertainty attaching to forecasts. In any case, the data must be up to date in order for the forecast to be as accurate as possible. In some cases the data used to predict the variable of interest is itself forecast. A forecast is not to be confused with a Budget, budgets are more specific, fixed-term financial plans used for resource allocation and control, while forecasts provide estimates of future financial performance, allowing for flexibility and adaptability to changing circumstances. Both tools are valuable in financial planning and decision-making, but they serve different functions.
Applications
Forecasting has applications in a wide range of fields where estimates of future conditions are useful. Depending on the field, accuracy varies significantly. If the factors that relate to what is being forecast are known and well understood and there is a significant amount of data that can be used, it is likely the final value will be close to the forecast. If this is not the case or if the actual outcome is affected by the forecasts, the reliability of the forecasts can be significantly lower.
Climate change and increasing energy prices have led to the use of Egain Forecasting for buildings. This attempts to reduce the energy needed to heat the building, thus reducing the emission of greenhouse gases. Forecasting is used in customer demand planning in everyday business for manufacturing and distribution companies.
While the veracity of predictions for actual stock returns are disputed through reference to the efficient-market hypothesis, forecasting of broad economic trends is common. Such analysis is provided by both non-profit groups as well as by for-profit private institutions.
Forecasting foreign exchange movements is typically achieved through a combination of chart and fundamental analysis. An essential difference between chart analysis and fundamental economic analysis is that chartists study only the price action of a market, |
https://en.wikipedia.org/wiki/NonStop%20SQL | NonStop SQL is a commercial relational database management system that is designed for fault tolerance and scalability, currently offered by Hewlett Packard Enterprise. The latest version is SQL/MX 3.4.
The product was originally developed by Tandem Computers. Tandem was acquired by Compaq in 1997. Compaq was later acquired by Hewlett-Packard in 2002. When Hewlett-Packard split in 2015 into HP Inc. and Hewlett Packard Enterprise, NonStop SQL and the rest of the NonStop product line went to Hewlett Packard Enterprise.
The product primarily is used for online transaction processing and is tailored for organizations that need high availability and scalability for their database system. Typical users of the product are stock exchanges, telecommunications, POS, and bank ATM networks.
History
NonStop SQL is designed to run effectively on parallel computers, adding functionality for distributed data, distributed execution, and distributed transactions.
First released in 1987, a second version in 1989 added the ability to run queries in parallel, and the product became fairly famous for being one of the few systems that scales almost linearly with the number of processors in the machine: adding a second CPU to an existing NonStop SQL server almost exactly doubled its performance.
The second version added /MP to its name, for Massively Parallel. A third version, NonStop SQL/MX, created a product that was more ANSI SQL compliant than its predecessor. NonStop SQL/MX has shipped on the NonStop platform since 2002, and can access tables created by NonStop SQL/MP, although only "Native SQL/MX tables" offer the ANSI compliance and many "Oracle-like" enhancements. The HP Neoview business intelligence platform was built using NonStop SQL as its origins. NonStop SQL/MX is HP's only OLTP database product.
Parts of the Neoview code base were open-sourced in 2014 under the name Trafodion, which is now a top-level Apache project.
See also
List of relational database management systems
Comparison of relational database management systems
Enscribe
NonStop (server computers)
Tandem Computers
References
External links
The NonStop Product website
Fault-tolerant computer systems
HP software
Proprietary database management systems |
https://en.wikipedia.org/wiki/San%20Jose%20CyberRays | San Jose CyberRays was a professional soccer team that played in the Women's United Soccer Association. The team played at Spartan Stadium on the South Campus of San José State University in San Jose, California. Stars included U.S. National Team star Brandi Chastain, WUSA Goalkeeper of the Year LaKeysia Beene, and leading scorer Julie Murray. Other memorable CyberRays were Brazilians Sissi and Katia, Tisha Venturini (from the U.S. National Team), and "ironwoman" Thori Bryan, who played every minute of the first season. They were coached by Ian Sawyers, who received WUSA Coach of the Year honors in 2001.
History
Establishment
The CyberRays were founded in 2000 as a member of the Women's United Soccer Association, the first professional women's soccer league in the United States. The league featured many of the stars from the 1999 FIFA Women's World Cup. The team featured United States women's national team players and league founding players Brandi Chastain, Tisha Venturini and LaKeysia Beene.
Year-by-year
Inaugural season
The team won the WUSA title (known as the Founders Cup) for the league's inaugural season in 2001. The CyberRays triumphed over the Atlanta Beat, in a 4–2 shootout after double overtime of a 3–3 game. It was the only year in the country's history that both a women's and men's professional soccer team won championship titles in the same city.
2002
In 2002 the team changed its name from the Bay Area CyberRays to the San Jose CyberRays, and also gave their roster a facelift, allowing Murray to retire and trading for Pretinha from the Washington Freedom, who along with Katia and Sissi, gave the new attack a decidedly Brazilian flavor. The bold changes didn't have the desired effect, however, and the team finished out of the playoffs. One bright spot was the emergence of Katia, who scored 15 goals and broke Tiffeny Milbrett's record for most points in a season.
2003
The CyberRays had high hopes for 2003, but an anemic offense (worst in the league in goals scored) hurt the team all year. The team remained in contention until the end of the season, but finished out of the playoffs for a second straight year.
But even bigger problems were brewing in the background, as the WUSA continued to struggle financially. The CyberRays folded on September 15, 2003, when the league announced it was suspending operations.
Players
2003 roster
Stadium
The CyberRays played at Spartan Stadium on the South Campus of San Jose State University in San Jose, California. The stadium was used for the 1999 FIFA Women's World Cup and was also the home of the San Jose Earthquakes of Major League Soccer from 1996 to 2005. At the time, the stadium featured a grass pitch and up to 30,456 capacity.
Broadcasting
In 2002, games were broadcast on television via PAX TV. California Bears assistant coach Jennifer Thomas provided color commentary while KCBS Radio sports announcer Hal Ramey was the play-by-play announcer. A number of league games were broadc |
https://en.wikipedia.org/wiki/Clipper%20%28programming%20language%29 | Clipper is an xBase compiler that implements a variant of the xBase computer programming language. It is used to create
or extend software programs that originally operated primarily under MS-DOS. Although it is a powerful general-purpose programming
language, it was primarily used to create database/business programs.
One major dBase feature not implemented in Clipper is the dot-prompt (. prompt) interactive command set, which was an important part of the original dBase implementation.
Clipper, from Nantucket Corp and later Computer Associates, started out as a native code compiler for dBase III databases, and later evolved.
History
Clipper was created by Nantucket Corporation, a company that was started in 1984 by Barry ReBell (management) and Brian Russell (technical);
Larry Heimendinger was Nantucket's president. In 1992, the company was sold to Computer Associates for 190 million dollars and the product was renamed to CA-Clipper.
Clipper was created as a replacement programming language for Ashton Tate's dBASE III, a very popular database language at the time. The advantage of Clipper over dBASE was that it could be compiled and executed under MS-DOS as a standalone application. In the years between 1985 and 1992, millions of Clipper applications were built, typically for small businesses dealing with databases concerning many aspects of client management and inventory management. For many smaller businesses, having a Clipper application designed to their specific needs was their first experience with software development. Also a lot of applications for banking and insurance companies were developed, here especially in those cases where the application was considered too small to be developed and run on traditional mainframes. In these environments Clipper also served as a front end for existing mainframe applications.
As the product matured, it remained a DOS tool for many years, but added elements of the C programming language and Pascal programming language, as well as OOP, and the code-block data-type (hybridizing the concepts of dBase macros, or string-evaluation, and function pointers), to become far more powerful than the original. Nantucket's Aspen project later matured into the Windows native-code CA-Visual Objects compiler.
Market penetration
Nantucket sold well in Western markets. Also, in November 1991, the New York Times reported the company's success in "painstakingly convincing Soviet software developers that buying is preferable to pirating". According to the article, Clipper had sold 2,000 copies in the Soviet Union (compared to 250,000 worldwide).
Decline
In the early 1990s, under new ownership, Clipper failed to transition from MS-DOS to Microsoft Windows. As a result, almost no new commercial applications were written in Clipper after 1995.
By then, the "classically trained programmer" commonly used strong typing, in contrast to the original dBASE language.
An evolution of Clipper, named VO, added strong ty |
https://en.wikipedia.org/wiki/Adele%20Goldberg%20%28computer%20scientist%29 | Adele Goldberg (born July 22, 1945) is an American computer scientist. She was one of the co-developers of the programming language Smalltalk-80 and of various concepts related to object-oriented programming while a researcher at the Xerox Palo Alto Research Center (PARC), in the 1970s.
Early life and education
Goldberg was born in Cleveland, Ohio, on July 22, 1945. Her parents moved to Chicago, Illinois when she was 11, where she spent the rest of her childhood. She enjoyed problem solving and mathematics from a young age and was encouraged by her teachers to pursue mathematics. In 1967, she earned a bachelor's degree in mathematics at the University of Michigan. Interested in the subject of computing, Goldberg worked as an intern with IBM during the summer of her junior year of college, where she learned how to program unit record machines. After graduating, she attended the University of Chicago, where she received her master's degree (in 1969) and a PhD (in 1973) in information science. She completed her dissertation, "Computer-Assisted Instruction: The Application of Theorem-proving to Adaptive Response Analysis," while working as a research associate at Stanford University. She also served as a visiting researcher at Stanford.
Career
Goldberg began working at PARC in 1973 as a laboratory and research assistant, and eventually became manager of the System Concepts Laboratory where she, Alan Kay, and other researchers developed the programming language Smalltalk-80. This language developed the object-oriented approach of Simula 67 and introduced a programming environment of overlapping windows on graphic display screens. Smalltalk's innovative format was simple to use and customizable. Objects could be transferred among applications with minimal effort. Goldberg and Kay were involved in the development of design templates, forerunners of the design patterns later used in software design.
Along with Kay, she wrote the influential article "Personal Dynamic Media", which predicted a world in which ordinary individuals would use notebook computers to exchange, modify, and redistribute personal media. This paper outlined the vision for the Dynabook.
Many of the concepts developed by Goldberg and her team at PARC became the basis for graphical user interfaces. According to Goldberg, Steve Jobs demanded a demonstration of the Smalltalk System, which she at first refused to give him, although her superiors eventually compelled her to comply. Apple eventually took many of the ideas used in the Xerox Alto and their implementations and used them as the basis for their Apple Macintosh desktop environment.
In 1988, Goldberg left PARC to cofound ParcPlace Systems, a company that created development tools for Smalltalk-based applications. There, she served as chairwoman and CEO until its 1995 merger with Digitalk. She also cofounded Neometron, Inc. an Internet support provider in 1999. She works at Bullitics. She continues to pursue her interest in |
https://en.wikipedia.org/wiki/Algorithmics%20Inc. | Algorithmics was a Toronto, Ontario based company founded by Ron Dembo that provided risk management software to financial institutions. Founded in 1989, Algorithmics employed over 850 people in 23 global offices, and served more than 350 clients, including 25 of the 30 largest banks in the world, and over two thirds of the CRO Forum of leading insurers.
In January 2005, Algorithmics was acquired by Fitch Group for $175 million, which is also the parent company of Fitch Ratings.
In October 2011, Algorithmics was acquired by IBM for $387 million. IBM OpenPages and Algorithmics will be combined to form a new Risk Analytics pillar within the Business Analytics software division.
Algorithmics was voted as the leading enterprise risk firm for market risk, economic capital risk calculation, risk dashboards and collateral management in Risk magazine's 2010 Technology Rankings. Algorithmics was also selected as the best Risk Analytics Solution Provider in Waters magazine's annual financial technology rankings. In 2011, Algorithmics won the Life and Pension Risk award for Best Solvency II provider. In 2007, Algorithmics was selected as one of Canada's Top 100 Employers, as published in Maclean's magazine.
In December 2019, SS&C Technologies acquired Algorithmics from IBM for $88.8 million.
See also
SunGard
References
A Program to Keep Tabs on Derivatives, The New York Times
PeopleSoft And Algorithmics Partner On Risk Management, Informationweek
Risk Vendor Algorithmics Acquired By Fitch, Informationweek
Risky Business, Fast Company
Countering The Domino Effect, US Banker: "According to this accepted view, the top-tier vendors are: Algorithmics Inc., Toronto; Infinity Financial Technology Inc., New York; and MKIRisk"
External links
Company Site
Parent Company Page
Software companies of Canada
Software companies established in 1989
Companies based in Toronto
Risk management companies
Information technology audit
2005 mergers and acquisitions
2011 mergers and acquisitions
IBM acquisitions
Canadian subsidiaries of foreign companies
2019 mergers and acquisitions |
https://en.wikipedia.org/wiki/Yellow%20Dog%20Linux | Yellow Dog Linux (YDL) is a discontinued free and open-source operating system for high-performance computing on multi-core processor computer architectures, focusing on GPU systems and computers using the POWER7 processor. The original developer was Terra Soft Solutions, which was acquired by Fixstars in October 2008. Yellow Dog Linux was first released in the spring of 1999 for Apple Macintosh PowerPC-based computers. The most recent version, Yellow Dog Linux 7, was released on August 6, 2012. Yellow Dog Linux lent its name to the popular YUM Linux software updater, derived from YDL's YUP (Yellowdog UPdater) and thus called Yellowdog Updater, Modified.
Features
Yellow Dog Linux is based on Red Hat Enterprise Linux/CentOS and relies on the RPM Package Manager. Its software includes applications such as Ekiga (a voice-over-IP and videoconferencing application), GIMP (a raster graphics editor), Gnash (a free Adobe Flash player), gThumb (an image viewer), the Mozilla Firefox Web browser, the Mozilla Thunderbird e-mail and news client, the OpenOffice.org productivity suite, Pidgin (an instant messaging and IRC client), the Rhythmbox music player, and the KDE Noatun and Totem media players.
Starting with YDL version 5.0 'Phoenix', Enlightenment is the Yellow Dog Linux default desktop environment, although GNOME and KDE are also included.
Like other Linux distributions, Yellow Dog Linux supports software development with GCC (compiled with support for C, C++, Java, and Fortran), the GNU C Library, GDB, GLib, the GTK+ toolkit, Python, the Qt toolkit, Ruby and Tcl. Standard text editors such as Vim and Emacs are complemented with IDEs such as Eclipse and KDevelop, as well as by graphical debuggers such as KDbg. Standard document preparation tools such as TeX and LaTeX are also included.
Yellow Dog Linux includes software for running a Web server (such as Apache/httpd, Perl, and PHP), database server (such as MySQL and PostgreSQL), and network server (NFS and Webmin). Additional software is also included for running an enterprise server or a compute server or cluster, although two separate products from Terra Soft Solutions, called Yellow Dog Enterprise Linux (for enterprise servers) and Y-HPC (for compute servers/clusters), were specifically targeted toward those applications.
Although several other Linux distributions support the Power ISA, Yellow Dog Linux was distinguished for its focus on supporting the Apple Macintosh platform before the Mac transition to Intel processors. Before this transition, Terra Soft Solutions held the unique distinction of being the only company licensed by Apple to resell Apple computers with Linux pre-installed (or for that matter, with any operating system other than Mac OS X). Full support for AirPort (Apple's implementation of the IEEE 802.11b-1999 wireless networking standard), and partial support for AirPort Extreme, are also built into Yellow Dog Linux, as are support for Bluetooth and support for accessing th |
https://en.wikipedia.org/wiki/Prisoner%20%28TV%20series%29 | Prisoner (known in the UK and the US as Prisoner: Cell Block H) is an Australian television soap opera, which broadcast on Network Ten (originally The 0-10 Network) from February 27 (Melbourne) February 26 (Sydney) 1979 to December 1986 (Melbourne), though the series finale would not screen until September 1987 in Sydney, where it aired as a three-hour film that was split into three one-hour episodes at the much-later time-slot of 10:30 p.m., running eight seasons and 692 episodes.
Prisoner was the first Australian series to feature a primarily female-dominated cast and carried the slogan "If you think prison is hell for a man, imagine what it would be like for a woman!"
The series, produced by the Grundy Organisation, was conceived by Reg Watson and filmed at the then Network Ten Melbourne Studios at Nunawading and on location.
The series garnered an international cult following, and it was one of Australia's most successful media exports, and was exported to 80 countries, performing particularly well in the United States and Canada (billed as Prisoner: Cell Block H and Caged Women, respectively). It also built a large audience in the United Kingdom and other European countries, especially Sweden.
Sammy Davis Jr. was a major fan and visited the set, and wanted to appear in a role, but had other engagements at the time.
The cult status of the series has seen many adaptations, including the modern 21st century re-imaging series Wentworth on Foxtel.
Background
Ian Bradley served as original producer and then executive producer, from series 2, whilst associate producer and screenwriter was Ian Smith, who appeared as an actor in the series as Head of the Department Ted Douglas, prior to becoming famous as the character Harold Bishop in Neighbours; another screenwriter, Anne Lucas, also acted briefly in the series playing prison bookie Faye Quinn.
The series is loosely based on British prison drama series Within These Walls, although it focuses more on the prisoners or inmates, rather than the prison staff led by officious governor Faye Boswell, played by Googie Withers, who was even approached by producers of Prisoner to play the governor.
The series is set in the fictional Wentworth Detention Centre in the fictional suburb of Wentworth in Melbourne, Victoria, and follows the lives of the prisoners and staff within cell block H and, to a lesser extent, others on the outside such as family members, doctors and lawyers. Numerous scenes also took place outside the compound exploring the lives of the inmates and staff outside of the prison; in particular, "Driscoll House", a halfway house where inmates were housed after being released, or neighbouring correction institutions like Barnhurst (a lower-security country prison) and Blackmoor (an aged, yet high-security, prison).
The series gained a positive reception. Initially conceived as a standalone miniseries of 16 episodes, its popularity meant it was developed into an ongoing series. It |
https://en.wikipedia.org/wiki/VIA%20C3 | The VIA C3 is a family of x86 central processing units for personal computers designed by Centaur Technology and sold by VIA Technologies. The different CPU cores are built following the design methodology of Centaur Technology.
In addition to x86 instructions, VIA C3 CPUs contain an undocumented Alternate Instruction Set allowing lower-level access to the CPU and in some cases privilege escalation.
Cores
Samuel 2 and Ezra cores
VIA Cyrix III was renamed VIA C3 with the switch to the advanced "Samuel 2" (C5B) core. The addition of an on-die L2 cache improved performance somewhat. As it was not built upon Cyrix technology at all, the new name was just a logical step. To improve power consumption and reduce manufacturing costs, Samuel 2 was produced with 150 nm process technology.
The VIA C3 processor continued an emphasis on minimizing power consumption with the next die shrink to a mixed 130/150 nm process. "Ezra" (C5C) and "Ezra-T" (C5N) were only new revisions of the "Samuel 2" core with some minor modifications to the bus protocol of "Ezra-T" to match compatibility with Intel's Pentium III "Tualatin" cores. VIA enjoyed the lowest power usage in the x86 CPU market for several years. Performance, however, fell behind due to the lack of improvements to the design.
Uniquely, the retail C3 CPU shipped inside a decorative tin.
Nehemiah cores
The "Nehemiah" (C5XL) was a major core revision. At the time, VIA's marketing efforts did not fully reflect the changes that had taken place. The company addressed numerous design shortcomings of the older cores, including the half-speed FPU. The number of pipeline stages was increased from 12 to 16, to allow for continued increases in clock speed. Additionally, it implemented the cmov instruction, making it a 686-class processor. The Linux kernel refers to this core as the C3-2. It also removes 3DNow! instructions in favour of implementing SSE. However, it was still based upon the aging Socket 370, running the single data rate front-side bus at just 133 MHz.
Because the embedded system marketplace prefers low-power, low-cost CPU designs, VIA began targeting this segment more aggressively because the C3 fit those traits rather well. Centaur Technology concentrated on adding features attractive to the embedded marketplace. An example built into the first "Nehemiah" (C5XL) core were the twin hardware random number generators. (These generators are erroneously called “quantum-based” in VIA's marketing literature. Detailed analysis of the generator makes it clear that the source of randomness is thermal, not quantum.)
The "Nehemiah+" (C5P) (stepping 8) revision brought a few more advancements, including a high-performance AES encryption engine along with a notably small ball grid array chip package the size of a US 1 cent coin. At the time VIA also boosted the FSB to 200 MHz and introduced new chipsets such as the CN400 to support it. The new 200 MHz FSB chips are only available in BGA packages, as they |
https://en.wikipedia.org/wiki/MMS | MMS may refer to:
Science and technology
Network communication protocols
Multimedia Messaging Service for mobile phones
Microsoft Media Server, a content-streaming protocol (mms://)
Manufacturing Message Specification for real time process data
Other
Magnetospheric Multiscale Mission, NASA
Massachusetts Medical Society
Methyl methanesulfonate
Moment magnitude scale of earthquake energy
Multiscale Modeling and Simulation journal
Schools
Modern Montessori School, Amman, Jordan
Marshall Middle School (Pittsburgh), US
Mayo Clinic School of Medicine, US, formerly Mayo Medical School
Margaret Mace School, the only school of the North Wildwood School District
Government and politics
Minerals Management Service, former U.S. agency
Movimento Mérito e Sociedade (Merit and Society Movement), Portuguese political party
Other uses
Machinist's mate (shop mechanic), US Navy
Master of Management, a postgraduate academic degree course.
Medical Mission Sisters, a religious congregation
Methodist Missionary Society of Australasia, a former division of the Methodist Church in Australia
Metro Manila Subway, an under-construction rapid transit line in Philippines
Metropolitan mountaineering society, Philippines
Miracle Mineral Supplement, bleach fraudulently sold as medicine
M.M.S. (Mobile Missile System), a G.I. Joe playset
MMS-class minesweeper, a class of British warships
See also
M&M's |
https://en.wikipedia.org/wiki/BS12 | BS12 may refer to:
IBM Business System 12, an early relational database management system
BS 12 Specification for Portland Cement, a British Standard
Bonomi BS.12 Roma, a primary glider
Omega BS-12, a utility helicopter |
https://en.wikipedia.org/wiki/ADS | ADS or Ads may refer to:
Advertising
In arts and entertainment
ADS (TV station), Adelaide, South Australia
"Aiming Down Sights", video game term
In science and technology
In computing
Advanced Design System, electronic design automation software
Alternate data stream in Microsoft NTFS
Automated decision support, rule-based systems for management
In military use
ADS amphibious rifle
Active Denial System, US non-lethal weapon
Air Defence Ship, Indian aircraft carrier designation
Other uses in science and technology
Accelerator-driven system, a type of subcritical reactor
Adaptive Damping System, Mercedes vehicle suspension
Aitken Double Star Catalogue
Anti–de Sitter space, a manifold in mathematics and physics
Archaeology Data Service
Astrophysics Data System
Atmospheric diving suit
Automatic dependent surveillance for tracking aircraft
Automated driving system
Autonomous Detection System for biohazards
Other uses
Adamorobe Sign Language, Ghana
Addison Airport, Texas, US, IATA and FAA codes
Adelaide Dolphin Sanctuary, a dolphin sanctuary in Adelaide, South Australia
ADS (motorcycle), a Belgian manufacturer
ADS Group, a British trade organisation
Advanced Drainage Systems, a US company that manufacturers PVC pipes
Agrarian Democratic Party, Czech Republic
Alliance Data Systems, NYSE code
American depositary share
American Dialect Society, a learned society dedicated to languages in the US
Ardrossan Harbour railway station, North Ayrshire, Scotland, station code
See also
AD (disambiguation) |
https://en.wikipedia.org/wiki/IBM%201720 | The IBM 1720 was a pilot project to create a real-time process control computer based on the IBM 1620 Model I.
Only three 1720 systems were ever built: one for the Amoco oil refinery in Whiting, Indiana; one for the Socal oil refinery in El Segundo, California; and one for E. I. du Pont in Wilmington, Delaware. All were installed in 1961. The Amoco and Socal systems ran for many years.
The 1720 led to the IBM 1710 Process Control systems that IBM introduced in March 1961; these were cheaper and less elaborate than the 1720.
See also
IBM 1710
IBM 1800
External links
"Evolution of Small Real-Time IBM Computer Systems" (1.25 MB PDF file), from the IBM Journal of Research and Development.
1720
Computer-related introductions in 1961
Amoco |
https://en.wikipedia.org/wiki/Hierarchical%20database%20model | A hierarchical database model is a data model in which the data are organized into a tree-like structure. The data are stored as records which are connected to one another through links. A record is a collection of fields, with each field containing only one value. The type of a record defines which fields the record contains.
The hierarchical database model mandates that each child record has only one parent, whereas each parent record can have one or more child records. In order to retrieve data from a hierarchical database, the whole tree needs to be traversed starting from the root node. This model is recognized as the first database model created by IBM in the 1960s.
History
The hierarchical structure was developed by IBM in the 1960s and used in early mainframe DBMS. Records' relationships form a treelike model. This structure is simple but inflexible because the relationship is confined to a one-to-many relationship. The IBM Information Management System (IMS) and RDM Mobile are examples of a hierarchical database system with multiple hierarchies over the same data.
The hierarchical data model lost traction as Codd's relational model became the de facto standard used by virtually all mainstream database management systems. A relational-database implementation of a hierarchical model was first discussed in published form in 1992 (see also nested set model). Hierarchical data organization schemes resurfaced with the advent of XML in the late 1990s (see also XML database). The hierarchical structure is used primarily today for storing geographic information and file systems.
Currently, hierarchical databases are still widely used especially in applications that require very high performance and availability such as banking, health care, and telecommunications. One of the most widely used commercial hierarchical databases is IMS.
Another example of the use of hierarchical databases is Windows Registry in the Microsoft Windows operating systems.
Examples of hierarchical data represented as relational tables
An organization could store employee information in a table that contains attributes/columns such as employee number, first name, last name, and department number. The organization provides each employee with computer hardware as needed, but computer equipment may only be used by the employee to which it is assigned. The organization could store the computer hardware information in a separate table that includes each part's serial number, type, and the employee that uses it. The tables might look like this:
In this model, the employee data table represents the "parent" part of the hierarchy, while the computer table represents the "child" part of the hierarchy.
In contrast to tree structures usually found in computer software algorithms, in this model the children point to the parents.
As shown, each employee may possess several pieces of computer equipment, but each individual piece of computer equipment may have only one em |
https://en.wikipedia.org/wiki/Communicating%20sequential%20processes | In computer science, communicating sequential processes (CSP) is a formal language for describing patterns of interaction in concurrent systems. It is a member of the family of mathematical theories of concurrency known as process algebras, or process calculi, based on message passing via channels. CSP was highly influential in the design of the occam programming language and also influenced the design of programming languages such as Limbo, RaftLib, Erlang, Go, Crystal, and Clojure's core.async.
CSP was first described in a 1978 article by Tony Hoare, but has since evolved substantially. CSP has been practically applied in industry as a tool for specifying and verifying the concurrent aspects of a variety of different systems, such as the T9000 Transputer, as well as a secure ecommerce system. The theory of CSP itself is also still the subject of active research, including work to increase its range of practical applicability (e.g., increasing the scale of the systems that can be tractably analyzed).
History
The version of CSP presented in Hoare's original 1978 article was essentially a concurrent programming language rather than a process calculus. It had a substantially different syntax than later versions of CSP, did not possess mathematically defined semantics, and was unable to represent unbounded nondeterminism. Programs in the original CSP were written as a parallel composition of a fixed number of sequential processes communicating with each other strictly through synchronous message-passing. In contrast to later versions of CSP, each process was assigned an explicit name, and the source or destination of a message was defined by specifying the name of the intended sending or receiving process. For example, the process
COPY = *[c:character; west?c → east!c]
repeatedly receives a character from the process named west and sends that character to process named east. The parallel composition
[west::DISASSEMBLE || X::COPY || east::ASSEMBLE]
assigns the names west to the DISASSEMBLE process, X to the COPY process, and east to the ASSEMBLE process, and executes these three processes concurrently.
Following the publication of the original version of CSP, Hoare, Stephen Brookes, and A. W. Roscoe developed and refined the theory of CSP into its modern, process algebraic form. The approach taken in developing CSP into a process algebra was influenced by Robin Milner's work on the Calculus of Communicating Systems (CCS) and conversely. The theoretical version of CSP was initially presented in a 1984 article by Brookes, Hoare, and Roscoe, and later in Hoare's book Communicating Sequential Processes, which was published in 1985. In September 2006, that book was still the third-most cited computer science reference of all time according to Citeseer (albeit an unreliable source due to the nature of its sampling). The theory of CSP has undergone a few minor changes since the publication of Hoare's book. Most of these changes were motivated by t |
https://en.wikipedia.org/wiki/Suggested%20Upper%20Merged%20Ontology | The Suggested Upper Merged Ontology (SUMO) is an upper ontology intended as a foundation ontology for a variety of computer information processing systems. SUMO defines a hierarchy of classes and related rules and relationships. These are expressed in a version of the language SUO-KIF, a higher-order logic that has a LISP-like syntax, as well as the TPTP family of languages. A mapping from WordNet synsets to SUMO has been defined. Initially, SUMO was focused on meta-level concepts (general entities that do not belong to a specific problem domain), and thereby would lead naturally to a categorization scheme for encyclopedias. It has now been considerably expanded to include a mid-level ontology and dozens of domain ontologies.
SUMO is organized for interoperability of automated reasoning engines. To maximize compatibility, schema designers can try to assure that their naming conventions use the same meanings as SUMO for identical words (for example, "agent" or "process"). SUMO has an associated open source Sigma knowledge engineering environment.
Initially, Sumo was developed by the Teknowledge Corporation and now is maintained by Articulate Software. SUMO is open source. The first release was in December 2000.
See also
Semantic translation
References
External links
Main page for SUMO
The Sigma reasoning system for SUMO
Online browser for SUMO
Adam Pease, creator and current Technical Editor of the standard
Home page of the IEEE Standard Upper Ontology working group
Java platform software
Knowledge representation
Ontology (information science)
Open data
Knowledge bases |
https://en.wikipedia.org/wiki/Gene%20Amdahl | Gene Myron Amdahl (November 16, 1922 – November 10, 2015) was an American computer architect and high-tech entrepreneur, chiefly known for his work on mainframe computers at IBM and later his own companies, especially Amdahl Corporation. He formulated Amdahl's law, which states a fundamental limitation of parallel computing.
Childhood and education
Amdahl was born to immigrant parents of Norwegian and Swedish descent in Flandreau, South Dakota. After serving in the Navy during World War II he completed a degree in engineering physics at South Dakota State University in 1948.
He went on to study theoretical physics at the University of Wisconsin–Madison under Robert G. Sachs. However, in 1950, Amdahl and Charles H. "Charlie" Davidson, a fellow PhD student in the Department of Physics, approached Harold A. Peterson with the idea of a digital computer. Amdahl and Davidson gained the support of Peterson and fellow electrical engineering professor Vincent C. Rideout, who encouraged them to build a computer of their unique design. Amdahl completed his doctorate at UW–Madison in 1952 with a thesis titled A Logical Design of an Intermediate Speed Digital Computer and created his first computer, the Wisconsin Integrally Synchronized Computer (WISC). He then went straight from Wisconsin to a position at IBM in June 1952.
IBM
At IBM, Amdahl worked on the IBM 704, the IBM 709, and then the Stretch project, the basis for the IBM 7030. He left IBM in December 1955, but returned in September 1960 (after working at Ramo-Wooldridge and at Aeronutronic). He quit out of frustration with the bureaucratic structure of the organization. In an interview conducted in 1989 for the Charles Babbage Institute, he addressed this:
On his return, he became chief architect of IBM System/360 and was named an IBM Fellow in 1965, and head of the ACS Laboratory in Menlo Park, California.
Amdahl Corporation
He left IBM again in September 1970, after his ideas for computer development were rejected, and set up Amdahl Corporation in Sunnyvale, California with major financing from Fujitsu.
Competing with IBM in the mainframe market, the company manufactured "plug-compatible" mainframes, shipping its first machine in 1975 – the Amdahl 470V/6, a less expensive, more reliable and faster replacement for the System 370/168. By purchasing an Amdahl 470 and plug-compatible peripheral devices from third-party manufacturers, customers could now run S/360 and S/370 applications without buying actual IBM hardware. Amdahl's software team developed VM/PE (Virtual Machine/Performance Enhancement), software designed to optimize the performance of IBM's MVS operating system when running under IBM's VM operating system.
By 1979, Amdahl Corporation had sold over US$1 billion of V6 and V7 mainframes and had over 6,000 employees worldwide. The corporation went on to distribute an IBM-plug-compatible front-end processor (the 4705) as well as high-performance disk drives, both jointly developed with |
https://en.wikipedia.org/wiki/Timeline%20of%20operating%20systems | This article presents a timeline of events in the history of computer operating systems from 1951 to the current day. For a narrative explaining the overall developments, see the History of operating systems.
1950s
1951
LEO I 'Lyons Electronic Office' was the commercial development of EDSAC computing platform, supported by British firm J. Lyons and Co.
1955
MIT's Tape Director operating system made for UNIVAC 1103
1955
General Motors Operating System made for IBM 701
1956
GM-NAA I/O for IBM 704, based on General Motors Operating System
1957
Atlas Supervisor (Manchester University) (Atlas computer project start)
BESYS (Bell Labs), for IBM 704, later IBM 7090 and IBM 7094
1958
University of Michigan Executive System (UMES), for IBM 704, 709, and 7090
1959
SHARE Operating System (SOS), based on GM-NAA I/O
1960s
1960
IBSYS (IBM for its 7090 and 7094)
1961
CTSS demonstration (MIT's Compatible Time-Sharing System for the IBM 7094)
MCP (Burroughs Master Control Program)
1962
Atlas Supervisor (Manchester University) (Atlas computer commissioned)
BBN Time-Sharing System
GCOS (GE's General Comprehensive Operating System, originally GECOS, General Electric Comprehensive Operating Supervisor)
1963
AN/FSQ-32, another early time-sharing system begun
CTSS becomes operational (MIT's Compatible Time-Sharing System for the IBM 7094)
JOSS, an interactive time-shared system that did not distinguish between operating system and language
Titan Supervisor, early time-sharing system begun
1964
Berkeley Timesharing System (for Scientific Data Systems' SDS 940)
Dartmouth Time Sharing System (Dartmouth College's DTSS for GE computers)
EXEC 8 (UNIVAC)
KDF9 Timesharing Director (English Electric) – an early, fully hardware secured, fully pre-emptive process switching, multi-programming operating system for KDF9 (originally announced in 1960)
OS/360 (IBM's primary OS for its S/360 series) (announced)
PDP-6 Monitor (DEC) descendant renamed TOPS-10 in 1970
SCOPE (CDC 3000 series)
1965
BOS/360 (IBM's Basic Operating System)
TOS/360 (IBM's Tape Operating System)
Livermore Time Sharing System (LTSS)
Multics (MIT, GE, Bell Labs for the GE-645) (announced)
Pick operating system
THE multiprogramming system (Technische Hogeschool Eindhoven) development
TSOS (later VMOS) (RCA)
1966
DOS/360 (IBM's Disk Operating System)
GEORGE 1 & 2 for ICT 1900 series
MS/8 (Richard F. Lary's DEC PDP-8 system)
OS/360 (IBM's primary OS for its S/360 series) PCP and MFT (shipped)
RAX
Remote Users of Shared Hardware (RUSH), a time-sharing system developed by Allen-Babcock for the 360/50
SODA for Elwro's Odra 1204
Universal Time-Sharing System (XDS Sigma series)
1967
CP-40, predecessor to CP-67 on modified IBM System/360 Model 40
CP-67 (IBM, also known as CP/CMS)
Conversational Programming System (CPS), an IBM time-sharing system under OS/360
Michigan Terminal System (MTS) (time-sharing system for the IBM S/360-67 and successors)
ITS (MIT's Inc |
https://en.wikipedia.org/wiki/Web%20Ontology%20Language | The Web Ontology Language (OWL) is a family of knowledge representation languages for authoring ontologies. Ontologies are a formal way to describe taxonomies and classification networks, essentially defining the structure of knowledge for various domains: the nouns representing classes of objects and the verbs representing relations between the objects.
Ontologies resemble class hierarchies in object-oriented programming but there are several critical differences. Class hierarchies are meant to represent structures used in source code that evolve fairly slowly (perhaps with monthly revisions) whereas ontologies are meant to represent information on the Internet and are expected to be evolving almost constantly. Similarly, ontologies are typically far more flexible as they are meant to represent information on the Internet coming from all sorts of heterogeneous data sources. Class hierarchies on the other hand tend to be fairly static and rely on far less diverse and more structured sources of data such as corporate databases.
The OWL languages are characterized by formal semantics. They are built upon the World Wide Web Consortium's (W3C) standard for objects called the Resource Description Framework (RDF). OWL and RDF have attracted significant academic, medical and commercial interest.
In October 2007, a new W3C working group was started to extend OWL with several new features as proposed in the OWL 1.1 member submission. W3C announced the new version of OWL on 27 October 2009. This new version, called OWL 2, soon found its way into semantic editors such as Protégé and semantic reasoners such as Pellet, RacerPro, FaCT++ and HermiT.
The OWL family contains many species, serializations, syntaxes and specifications with similar names. OWL and OWL2 are used to refer to the 2004 and 2009 specifications, respectively. Full species names will be used, including specification version (for example, OWL2 EL). When referring more generally, OWL Family will be used.
History
Early ontology languages
There is a long history of ontological development in philosophy and computer science. Since the 1990s, a number of research efforts have explored how the idea of knowledge representation (KR) from artificial intelligence (AI) could be made useful on the World Wide Web. These included languages based on HTML (called SHOE), based on XML (called XOL, later OIL), and various frame-based KR languages and knowledge acquisition approaches.
Ontology languages for the web
In 2000 in the United States, DARPA started development of DAML led by James Hendler.
In March 2001, the Joint EU/US Committee on Agent Markup Languages decided that DAML should be merged with OIL.
The EU/US ad hoc Joint Working Group on Agent Markup Languages was convened to develop DAML+OIL as a web ontology language. This group was jointly funded by the DARPA (under the DAML program) and the European Union's Information Society Technologies (IST) funding project. DAML+OIL was intended to be |
https://en.wikipedia.org/wiki/IBM%20i | IBM i (the i standing for integrated) is an operating system developed by IBM for IBM Power Systems. It was originally released in 1988 as OS/400, as the sole operating system of the IBM AS/400 line of systems. It was renamed to i5/OS in 2004, before being renamed a second time to IBM i in 2008. It is an evolution of the System/38 CPF operating system, with compatibility layers for System/36 SSP and AIX applications. It inherits a number of distinctive features from the System/38 platform, including the Machine Interface, the implementation of object-based addressing on top of a single-level store, and the tight integration of a relational database into the operating system.
History
Origin
OS/400 was developed alongside the AS/400 hardware platform beginning in December 1985. Development began in the aftermath of the failure of the Fort Knox project, which left IBM without a competitive midrange system. During the Fort Knox project, a skunkworks project was started at Rochester by engineers, who succeeded in developing code which allowed System/36 applications to run on top of the System/38, and when Fort Knox was cancelled, this project evolved into an official project to replace both the System/36 and System/38 with a single new hardware and software platform. The project became known as Silverlake (named for Silver Lake in Rochester, Minnesota).
The operating system for Silverlake was codenamed XPF (Extended CPF), and had originally begun as a port of CPF to the Fort Knox hardware. In addition to adding support for System/36 applications, some of the user interface and ease-of-use features from the System/36 were carried over to the new operating system.
Silverlake was available for field test in June 1988, and was officially announced in August of that year. By that point, it had been renamed to the Application System/400, and the operating system had been named Operating System/400.
The move to PowerPC
The port to PowerPC required a rewrite of most of the code below the TIMI. Early versions of OS/400 inherited the Horizontal and Vertical Microcode layers of the System/38, although they were renamed to the Horizontal Licensed Internal Code (HLIC) and Vertical Licensed Internal Code (VLIC) respectively. The port to the new hardware led to the IMPI instruction set and the horizontal microcode implementing it being replaced by the PowerPC AS instruction set and its implementation in PowerAS processors. This required the VLIC to be rewritten to target PowerPC instead of IMPI, and for the operating system functionality previously implemented in the HLIC to be re-implemented elsewhere. This led to the HLIC and VLIC being replaced with a single layer named the System Licensed Internal Code (SLIC). The SLIC was implemented in an object-oriented style with over 2 million lines of C++ code, replacing some of the HLIC code, and most of the VLIC code. Owing to the amount of work needed to implement the SLIC, IBM Rochester hired several hundred C+ |
https://en.wikipedia.org/wiki/Apple%20IIGS | The Apple IIGS (styled as II), the fifth and most powerful of the Apple II family, is a 16-bit personal computer produced by Apple Computer. While featuring the Macintosh look and feel, and resolution and color similar to the Amiga and Atari ST, it remains compatible with earlier Apple II models. The "GS" in the name stands for "Graphics and Sound", referring to its enhanced multimedia hardware, especially its state-of-the-art audio.
The microcomputer is a radical departure from any previous Apple II, with a 16-bit 65C816 microprocessor, direct access to megabytes of random-access memory (RAM), and bundled mouse. It is the first computer from Apple with a color graphical user interface (color was introduced on the Macintosh II six months later) and Apple Desktop Bus interface for keyboards, mice, and other input devices. It is the first personal computer with a wavetable synthesis chip, utilizing technology from Ensoniq.
The IIGS set forth a promising future and evolutionary advancement of the Apple II line, but Apple chose to focus on the Macintosh and no new Apple IIGS models were released. Apple ceased IIGS production in December 1992.
Hardware
The Apple IIGS made significant improvements over the Apple IIe and Apple IIc. It emulates its predecessors via a custom chip called the Mega II and uses the then-new WDC 65C816 16-bit microprocessor. The processor runs at , which is faster than the 8-bit processors used in the earlier Apple II models. The 65C816 allows the IIGS to address considerably more RAM.
The clock was a deliberate decision to limit the IIGS's performance to less than that of the Macintosh. This decision had a critical effect on the IIGS's success; the original 65C816 processor used in the IIGS was certified to run at up to . Faster versions of the 65C816 processor were readily available, with speeds of between 5 and 14 MHz, but Apple kept the machine at 2.8 MHz throughout its production run.
Its graphical capabilities are superior to the rest of the Apple II series, with higher resolution video modes and more color. These include a 640×200-pixel mode with 2-bit color and a 320×200 mode with 4-bit color, both of which can select 4 or 16 colors (respectively) at a time from a palette of 4,096 colors. By changing the palette on each scanline, it is possible to display up to 256 colors or more per screen. With clever programming, it is possible to make the IIGS display as many as 3,200 colors at once.
Audio is generated by a built-in Ensoniq 5503 digital synthesizer chip, which has its own dedicated RAM and 32 channels of sound. These channels can be paired to produce 15 voices in stereo.
The IIGS supports both 5.25-inch and 3.5-inch floppy disks and has seven general-purpose expansion slots compatible with those on the Apple II, II+, and IIe. It also has a memory expansion slot for up to 8 MB of RAM. The IIGS has ports for external floppy disk drives, two serial ports for devices such as printers and modems (which can als |
https://en.wikipedia.org/wiki/CBC%20Radio%20One | CBC Radio One is the English-language news and information radio network of the publicly owned Canadian Broadcasting Corporation. It is commercial-free and offers local and national programming. It is available on AM and FM to 98 percent of Canadians and overseas over the Internet, and through mobile apps. CBC Radio One is simulcast across Canada on Bell Satellite TV satellite channels 956 and 969, and Shaw Direct satellite channel 870.
A modified version of Radio One, with local content replaced by additional airings of national programming, is available on Sirius XM channel 169. It is downlinked to subscribers via SiriusXM Canada and its U.S.-based counterpart, Sirius XM Satellite Radio.
In 2010, Radio One reached 4.3 million listeners each week. It was the largest radio network in Canada.
History
CBC Radio began in 1936, and is the oldest branch of the corporation. In 1949, the facilities and staff of the Broadcasting Corporation of Newfoundland were transferred to CBC upon Newfoundland's entry into Canadian Confederation.
Beginning in 1944, the CBC operated two English-language radio services: the original network became the Trans-Canada Network, and a second network, the Dominion Network, was established with CJBC in Toronto as its flagship. With the exception of CJBC, all 35 stations on the CBC Dominion Network were privately owned affiliates. Its programming tended to be lighter than that of the Trans-Canada Network, carrying more American programming in its schedule. The Dominion Network operated only in the evenings, freeing affiliates to air local programming during the day.
Until 1958, the CBC was both a broadcaster, and the principal broadcast regulator in Canada. It used this dual role to take most of Canada's clear-channel frequencies on the AM band.
In 1962, the Dominion Network was dissolved and within a few years CJBC became a French-language station broadcasting the programming of Radio-Canada.
In 1960, the CBC began running distinct programming on its three existing FM English-language stations, which had been providing simulcasts of programming on its AM stations. The stations, located in Toronto, Ottawa and Montreal, broadcast a monoaural FM signal. Programming consisted mostly of classical music. The stations were linked by CN/CP Telecommunications via land-line and microwave. This service was discontinued in 1962, but resumed in 1964 in stereo. Eventually, a national satellite-distributed network of stereo FM stations was established. In 1975, the FM network was called CBC Stereo, and the AM service was designated CBC Radio.
In the late 1960s and early 1970s, CBC Radio increased its current affairs and documentary content with an initiative known as the "Radio Revolution", using more ambitious, live coverage of news and current affairs including listeners as well as experts. The change began with national shows such as As It Happens. The change spread to CBC regional morning shows which developed three hours of live |
https://en.wikipedia.org/wiki/TechTV | TechTV was a 24-hour cable and satellite channel based in San Francisco featuring news and shows about computers, technology, and the Internet. In 2004, it merged with the G4 gaming channel which ultimately dissolved TechTV programming. At the height of its six-year run, TechTV was broadcast in 70 countries, reached 43 million households, and claimed 1.9 million unique visitors monthly to its website. A focus on personality-driven product reviews and technical support made it a cultural hub for technology information worldwide, still existing today online through its former hosts' webcasts, most notably the TWiT Network.
The offices were located at 650 Townsend Street, 94103, and the studios, of which there were two, were located at 535 York Street, 94110.
History
ZDTV
On May 6, 1997, computer magazine publisher Ziff Davis announced its plan to launch a 24-hour interactive cable network specializing in computers and the Internet. The publisher put $100 million behind the project and planned to debut the channel, titled ZDTV, in early 1998. Projected programming for the channel included talk shows on the impact of technology, business-oriented shows evaluating investments in high-tech stocks, and reviews of software and hardware. Children's programming was also planned for the weekends. The channel had 11 initial charter advertisers, including IBM, Gateway 2000, Microsoft, and Charles Schwab. Ziff Davis chairman and CEO Eric Hippeau cited the increasing presence of computers in cable television homes and workspaces as motivation for filling the niche of programming about computers, saying "This is a huge audience and it will only get bigger".
The channel launched on Monday May 11, 1998, on cable systems in Las Vegas, Detroit, parts of Georgia near Atlanta and parts of Maine. An early adopter of ZDTV was Charter Communications (also owned by Paul Allen at the time), which began carrying the channel in Newnan, Georgia in July 1998. On August 1, 1998, ZDTV was broadcast in its native San Francisco when the channel struck a deal with DirecTV to become available on Channel 273 via the providers' satellite dishes.
Vulcan Ventures first invested in ZDTV, a network that supplemented content from Ziff-Davis' computer and technology based print publications (at the time including PC Magazine, MacWEEK, and eWEEK), in November 1998, acquiring a one-third interest from Ziff-Davis. In November 1999, Vulcan purchased the remaining two-thirds in a transaction that was completed on January 21, 2000. The deal (which permitted Vulcan to temporarily continue using the "ZD" initials and "red diamond" logo) was worth approximately $204.8 million. In July 2000, it was announced that ZDNet would be acquired by CNET, placing ZDTV in the awkward position of using the initials and logo of a company that soon would belong to its main TV programming rival. However, a new name was already being worked on.
TechTV
On September 18, 2000, ZDTV was renamed TechTV, and a new |
https://en.wikipedia.org/wiki/HSTN | HSTN (an acronym for High School Television Network) was a short-lived Canadian English language category 2 digital cable specialty channel aimed at high school students.
History
On June 4, 2001, Frank Rogers, on behalf of a company to be incorporated, was granted approval from the Canadian Radio-television and Telecommunications Commission (CRTC) to launch a national English-language Category 2 specialty television service called The High School Television Network, described as "devoted to the lifestyles of high school students across Canada. Programming will focus on high school sports (non-professional), drama, music, concerts within the school system, talk and panel shows and news coverage of events pertaining to or affecting the student population. High School Television Network will also provide a medium to broadcast student films or videos completed as a class project or ventures on their own."
The channel launched in August 2002 as HSTN on Rogers Cable.
It planned to show high school sports, concerts, dance programs, plays, high school news and information, among others. During its early existence, however, it showed very little besides endless repeats of Sponsé, an amateur film made by high school students in Toronto. The channel signed off on October 15, 2002.
On February 28, 2003, HSTN Inc. was placed in receivership and was to be temporarily managed by SF Partners Inc. On September 30, 2005, SF Partners purchased the channel and planned to renamed it YES-TV. The channel was intended to relaunch at a later date. However, the service did not launch as intended.
See also
Varsity TV (similarly-formatted channel in the US, also defunct)
References
Defunct television networks in Canada
Television channels and stations established in 2002
Television channels and stations disestablished in 2002
2002 establishments in Ontario
2002 disestablishments in Ontario |
https://en.wikipedia.org/wiki/Microsoft%20Agent | Microsoft Agent was a technology developed by Microsoft which employed animated characters, text-to-speech engines, and speech recognition software to enhance interaction with computer users. Thus it was an example of an embodied agent. It came pre-installed as part of Windows 2000 through Windows Vista. It was not included with Windows 7 but can be downloaded from Microsoft. It was completely discontinued in Windows 8. Microsoft Agent functionality was exposed as an ActiveX control that can be used by web pages.
The theory behind this software came from work on social interfaces by Clifford Nass and Byron Reeves at Stanford's Center for the Study of Language and Information.
Version history
Interactive character technology was first introduced in Microsoft Bob, which used an early version of Agent technology internally referred to as "Microsoft Actor." It was the code used in the initial version of the Office Assistant in Office 97. Microsoft Agent was subsequently created by Tandy Trower in an attempt to offer technology that was more flexible and available to third-party developers to include in their applications and web pages. The software release also included four interactive characters as well as a utility that enables developers to assemble their own characters and interactions.
Microsoft Agent replaced the original Microsoft Actor code in Office 2000, although this use did not include Agent's much-touted speech synthesis or recognition capabilities or any of the four Microsoft Agent characters. Instead the Office team created their own characters including one dubbed "Clippit" or "Clippy". However, Bob Actors or Office 97 assistants are incompatible with Office 2000 and later versions, and vice versa.
The current version of Microsoft Agent was quietly released on MSDN in 1997.
Technology
Microsoft Agent characters are stored in files of the .ACS extension, and can be stored in a number of compressed .ACF files for better World Wide Web distribution. Microsoft Office 97 and Microsoft Bob Actor characters are stored in files of the .ACT extension. Microsoft Agent character definition files are stored in files of the .ACD file extension, and are generated by the Microsoft Agent Character Editor.
The speech engine itself is driven by the Microsoft Speech API (SAPI), version 4 and above. Microsoft SAPI provides a control panel for easily installing and switching between various available Text to Speech and Speech to Text engines, as well as voice training and scoring systems to improve the quality and accuracy of both engines.
Microsoft provides four agent characters for free, which can be downloaded from the Microsoft Agent website. These are called Peedy, Merlin, Genie, and Robby. Some characters also shipped with Microsoft Office up to version 2003 as the Office Assistants and with Windows XP as search assistants. New Agent characters can also be created using Microsoft's development tools, including the Agent Character Editor. A |
https://en.wikipedia.org/wiki/Clique%20problem | In computer science, the clique problem is the computational problem of finding cliques (subsets of vertices, all adjacent to each other, also called complete subgraphs) in a graph. It has several different formulations depending on which cliques, and what information about the cliques, should be found. Common formulations of the clique problem include finding a maximum clique (a clique with the largest possible number of vertices), finding a maximum weight clique in a weighted graph, listing all maximal cliques (cliques that cannot be enlarged), and solving the decision problem of testing whether a graph contains a clique larger than a given size.
The clique problem arises in the following real-world setting. Consider a social network, where the graph's vertices represent people, and the graph's edges represent mutual acquaintance. Then a clique represents a subset of people who all know each other, and algorithms for finding cliques can be used to discover these groups of mutual friends. Along with its applications in social networks, the clique problem also has many applications in bioinformatics, and computational chemistry.
Most versions of the clique problem are hard. The clique decision problem is NP-complete (one of Karp's 21 NP-complete problems). The problem of finding the maximum clique is both fixed-parameter intractable and hard to approximate. And, listing all maximal cliques may require exponential time as there exist graphs with exponentially many maximal cliques. Therefore, much of the theory about the clique problem is devoted to identifying special types of graph that admit more efficient algorithms, or to establishing the computational difficulty of the general problem in various models of computation.
To find a maximum clique, one can systematically inspect all subsets, but this sort of brute-force search is too time-consuming to be practical for networks comprising more than a few dozen vertices.
Although no polynomial time algorithm is known for this problem, more efficient algorithms than the brute-force search are known. For instance, the Bron–Kerbosch algorithm can be used to list all maximal cliques in worst-case optimal time, and it is also possible to list them in polynomial time per clique.
History and applications
The study of complete subgraphs in mathematics predates the "clique" terminology. For instance, complete subgraphs make an early appearance in the mathematical literature in the graph-theoretic reformulation of Ramsey theory by . But the term "clique" and the problem of algorithmically listing cliques both come from the social sciences, where complete subgraphs are used to model social cliques, groups of people who all know each other. used graphs to model social networks, and adapted the social science terminology to graph theory. They were the first to call complete subgraphs "cliques". The first algorithm for solving the clique problem is that of , who were motivated by the sociological application |
https://en.wikipedia.org/wiki/Computer%20terminal | A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal and predated the use of a computer screen by decades.
Early terminals were inexpensive devices but very slow compared to punched cards or paper tape for input, yet as the technology improved and video displays were introduced, terminals pushed these older forms of interaction from the industry. A related development was time-sharing systems, which evolved in parallel and made up for any inefficiencies in the user's typing ability with the ability to support multiple users on the same machine, each at their own terminal or terminals.
The function of a terminal is typically confined to transcription and input of data; a device with significant local, programmable data-processing capability may be called a "smart terminal" or fat client. A terminal that depends on the host computer for its processing power is called a "dumb terminal" or a thin client. In the era of serial (RS-232) terminals there was a conflicting usage of the term "smart terminal" as a dumb terminal with no user-accessible local computing power but a particularly rich set of control codes for manipulating the display; this conflict was not resolved before hardware serial terminals became obsolete.
A personal computer can run terminal emulator software that replicates functions of a real-world terminal, sometimes allowing concurrent use of local programs and access to a distant terminal host system, either over a direct serial connection or over a network using, e.g., SSH.
History
The console of Konrad Zuse's Z3 had a keyboard in 1941, as did the Z4 in 1942–1945. But these consoles could only be used to enter numeric inputs and were thus analogous to those of calculating machines; programs, commands, and other data were entered via paper tape. Both machines had a row of display lamps for results.
In 1955, the Whirlwind Mark I computer was the first computer equipped with a keyboard-printer combination with which to support direct input of data and commands and output of results. The device was a Friden Flexowriter, which would continue to serve this purpose on many other early computers well into the 1960s.
Categories
Hard-copy terminals
Early user terminals connected to computers were, like the Flexowriter, electromechanical teleprinters/teletypewriters (TeleTYpewriter, TTY), such as the Teletype Model 33, originally used for telegraphy; early Teletypes were typically configured as Keyboard Send-Receive (KSR) or Automatic Send-Receive (ASR), the latter including a paper tape reader and punch. This led to the use of the current loop interface that was already used in telegraphy, as well as a thriving market in surplus machines for computer use.
Custom-designs keyboard/printer terminals that came later included the IBM 2741 (1965) and the |
https://en.wikipedia.org/wiki/Boss%20%28video%20games%29 | In video games, a boss is a significant computer-controlled opponent. A fight with a boss character is commonly referred to as a boss battle or boss fight. Bosses are generally far stronger than other opponents the player has faced up to that point. Boss battles are generally seen at climax points of particular sections of games, such as at the end of a level or stage or guarding a specific objective. A miniboss is a boss weaker or less significant than the main boss in the same area or level, though usually more powerful than the standard opponents and often fought alongside them. A superboss (sometimes 'secret', 'hidden' or 'raid' boss) is generally much more powerful than the bosses encountered as part of the main game's plot and is often an optional encounter. A final boss is often the main antagonist of a game's story and the defeat of that character usually provides a positive conclusion to the game. A boss rush is a stage where the player faces multiple previous bosses again in succession.
For example, in a run 'n' gun video game, all regular enemies might use pistols while the boss uses a tank. A boss enemy is quite often larger in size than other enemies and the player character. At times, bosses are very hard, even impossible, to defeat without being adequately prepared and/or knowing the correct fighting approach. Bosses usually take strategy and special knowledge to defeat, such as how to attack weak points or avoid specific attacks.
Bosses are common in many genres of video games, but they are especially common in story-driven titles, and are commonly previously established antagonists in the plot of the video game. Action-adventures, beat 'em ups, fighting games, platform games, role-playing video games (RPGs), and shooter games are particularly associated with boss battles. They may be less common in puzzle games, card video games, sports games, and simulation games. The first video game with a boss fight was the 1975 RPG dnd.
The concept has expanded to new genres, like rhythm games, where there may be a "boss song" that is more difficult. In MOBA games, defeating a map boss usually requires help from the other players, but it brings various benefits to the team, such as buffs or lane push power. Some games, such as Cuphead, Furi and Warning Forever, are centered around continual boss fights.
Characteristics
Bosses are usually harder to beat than regular enemies, can sustain more damage and are generally found at the end of a level or area. While most games include a mixture of boss opponents and regular opponents, some games have only regular opponents and some games have only bosses (e.g. Shadow of the Colossus). Some bosses are encountered several times through a single game, typically with alternate attacks and a different strategy required to defeat it each time. A boss battle can also be made more challenging if the boss in question becomes progressively stronger and/or less vulnerable as their health decreases, requirin |
https://en.wikipedia.org/wiki/XT | XT may refer to:
Science and technology
Computing and electronics
XT Mobile Network, a Telecom New Zealand mobile network
IBM PC/XT, a personal computer
XT bus architecture
Crosstalk, an electrical interference caused by a wire carrying an electrical signal
the XT versions of Radeon graphics cards
XT (or XT[2]), a video server from EVS Broadcast Equipment
XT XSLT, an implementation in Java of XSLT, created by James Clark
X Toolkit Intrinsics or X toolkit, or Xt, a library providing an object-oriented-looking API for the X Window System
Canon Digital Rebel XT, a digital single-lens reflex camera
Vehicles
Ford XT Falcon, a car produced by the Ford Motor Company in Australia between 1968 and 1969
Moyes XT, an Australian hang glider design
Subaru XT, a sports car
Yamaha XT 600 (and other XT versions), an enduro motorcycle
Other uses
XT Brewing Company, an English Microbrewery
XT (band), a Swedish metal band
Extra time, in sport
Cross-training, in sport
Air Exel (IATA airline code XT)
Christmas tree (oil well)
Bop It! XT, a 2011 electronic game |
https://en.wikipedia.org/wiki/Cambridge%20Ring%20%28computer%20network%29 | The Cambridge Ring was an experimental local area network architecture developed at the Computer Laboratory, University of Cambridge starting in 1974 and continuing into the 1980s. It was a ring network with a theoretical limit of 255 nodes (though such a large number would have badly affected performance), around which cycled a fixed number of packets. Free packets would be "loaded" with data by a sending machine, marked as received by the destination machine, and "unloaded" on return to the sender; thus in principle, there could be as many simultaneous senders as packets. The network ran over twin twisted-pair cabling (plus a fibre-optic section).
There are strong similarities between the Cambridge Ring and an earlier ring network developed at Bell Labs based on a design by John R. Pierce. That network used T1 lines at bit rate of 1.544 MHz and accommodating 522 bit messages (data plus address).
People associated with the project include Andy Hopper, David Wheeler, Maurice Wilkes, and Roger Needham.
In 2002, the Computer Laboratory launched a graduate society called the Cambridge Computer Lab Ring named after the Cambridge Ring.
See also
Cambridge Distributed Computing System
Internet in the United Kingdom § History
JANET
NPL network
Packet switching
Token Ring
University of London Computer Centre
References
External links
Cambridge Ring Hardware
Cambridge Fast Ring
Cambridge Backbone Ring Hardware
Cambridge Computer Lab Ring
1974 introductions
Experimental computer networks
History of computing in the United Kingdom
Local area networks
Network topology
University of Cambridge Computer Laboratory |
https://en.wikipedia.org/wiki/Open%20Source%20Development%20Labs | Open Source Development Labs (OSDL) was a non-profit organization supported by a consortium to promote Linux for enterprise computing. Founded in 2000, OSDL positioned itself as an independent, non-profit lab for developers who are adding enterprise capabilities to Linux. The headquarters was first incorporated in San Francisco but later relocated to Beaverton in Oregon with second facility in Yokohama, Japan.
On January 22, 2007, OSDL and the Free Standards Group merged to form the Linux Foundation, narrowing their respective focuses to that of promoting Linux.
Activities
OSDL sponsored projects, including industry initiatives to enhance Linux for use in corporate data centres, in telecommunications networks, and on desktop computers. It also:
provided hardware resources to the free software community and the open source community
tested and reported on open source software
employed a number of Linux developers.
Its employees included Linus Torvalds, the first OSDL fellow, and Bryce Harrington. In 2005, Andrew "Tridge" Tridgell was the second OSDL fellow for a year.
It had data centers in Beaverton (Oregon, United States) and Yokohama (Japan).
OSDL had investment backers that included: 7 funders of Computer Associates, Fujitsu, Hitachi, Ltd., Hewlett-Packard, IBM, Intel Corporation, Nippon Electric Corporation, as well as a large collection of independent software vendors, end-user companies and educational institutions. A steering committee composed of representatives from the investment backers directed OSDL, which also had a significant staff of its own.
Working groups
OSDL had established five Working Groups since 2002:
Mobile Linux Initiative
Carrier Grade Linux
Data Center Linux
Desktop Linux
User Advisory Council
See also
Patent Commons, a project launched in November 2005 by the OSDL
References
Free and open-source software organizations
Organizations disestablished in 2007
Defunct companies based in Oregon
Linux Foundation
Buildings and structures in Beaverton, Oregon
Companies established in 2000
Laboratories in Oregon
2007 disestablishments in Oregon |
https://en.wikipedia.org/wiki/Ampex | Ampex Data Systems Corporation is an American electronics company founded in 1944 by Alexander M. Poniatoff as a spin-off of Dalmo-Victor. The name AMPEX is a portmanteau, created by its founder, which stands for Alexander M. Poniatoff Excellence. Ampex operates as Ampex Data Systems Corporation, a subsidiary of Delta Information Systems, and consists of two business units. The Silicon Valley unit, known internally as Ampex Data Systems (ADS), manufactures digital data storage systems capable of functioning in harsh environments. The Colorado Springs, Colorado, unit, referred to as Ampex Intelligent Systems (AIS), serves as a laboratory and hub for the company's line of industrial control systems, cyber security products and services and its artificial intelligence/machine learning technology.
Ampex's first great success was a line of reel-to-reel tape recorders developed from the German wartime Magnetophon system at the behest of Bing Crosby. Ampex quickly became a leader in audio tape technology, developing many of the analog recording formats for both music and movies that remained in use into the 1990s. Starting in the 1950s, the company began developing video tape recorders, and later introduced the helical scan concept that made home video players possible. They also introduced multi-track recording, slow-motion and instant playback television, and a host of other advances. Ampex's tape business was rendered obsolete during the 1990s, and the company turned to digital storage products.
Ampex moved into digital storage for DoD Flight Test Instrumentation (FTI) with the introduction of the first, true all digital flight test recorder. Ampex supports numerous major DoD programs with the US Air Force, US Army, US Marines, US Navy and other government entities (NASA, DHS and national labs). Ampex also works with all major DoD primes and integrators including Boeing, General Atomics, Lockheed, Northrop, Raytheon and many others.
Currently, Ampex is attempting to do more with the data stored on its network attached storage (NAS) devices. This includes adding encryption for secure data storage; algorithms focused on control system cyber security for infrastructure and aerospace platforms; and artificial intelligence/machine learning for automated entity identification and data analytics.
Origin
Russian–American inventor Alexander Matthew Poniatoff established the company in San Carlos, California, in 1944 as the Ampex Electric and Manufacturing Company. The company name came from his initials plus "ex" to avoid using the name AMP already in use (by Aircraft and Marine Products). During World War II, Ampex was a subcontractor to Dalmo-Victor, manufacturing high quality electric motors and generators for radars that used alnico 5 magnets from General Electric. Ampex was initially set up in an abandoned loft-space above the Dalmo-Victor plant; eventually they would have offices at 1313 Laurel Street, San Carlos, California (at the intersection o |
https://en.wikipedia.org/wiki/Treap | In computer science, the treap and the randomized binary search tree are two closely related forms of binary search tree data structures that maintain a dynamic set of ordered keys and allow binary searches among the keys. After any sequence of insertions and deletions of keys, the shape of the tree is a random variable with the same probability distribution as a random binary tree; in particular, with high probability its height is proportional to the logarithm of the number of keys, so that each search, insertion, or deletion operation takes logarithmic time to perform.
Description
The treap was first described by Raimund Seidel and Cecilia R. Aragon in 1989; its name is a portmanteau of tree and heap.
It is a Cartesian tree in which each key is given a (randomly chosen) numeric priority. As with any binary search tree, the inorder traversal order of the nodes is the same as the sorted order of the keys. The structure of the tree is determined by the requirement that it be heap-ordered: that is, the priority number for any non-leaf node must be greater than or equal to the priority of its children. Thus, as with Cartesian trees more generally, the root node is the maximum-priority node, and its left and right subtrees are formed in the same manner from the subsequences of the sorted order to the left and right of that node.
An equivalent way of describing the treap is that it could be formed by inserting the nodes highest priority-first into a binary search tree without doing any rebalancing. Therefore, if the priorities are independent random numbers (from a distribution over a large enough space of possible priorities to ensure that two nodes are very unlikely to have the same priority) then the shape of a treap has the same probability distribution as the shape of a random binary search tree, a search tree formed by inserting the nodes without rebalancing in a randomly chosen insertion order. Because random binary search trees are known to have logarithmic height with high probability, the same is true for treaps. This mirrors the binary search tree argument that quicksort runs in expected time. If binary search trees are solutions to the dynamic problem version of sorting, then Treaps correspond specifically to dynamic quicksort where priorities guide pivot choices.
Aragon and Seidel also suggest assigning higher priorities to frequently accessed nodes, for instance by a process that, on each access, chooses a random number and replaces the priority of the node with that number if it is higher than the previous priority. This modification would cause the tree to lose its random shape; instead, frequently accessed nodes would be more likely to be near the root of the tree, causing searches for them to be faster.
Naor and Nissim describe an application in maintaining authorization certificates in public-key cryptosystems.
Operations
Basic operations
Treaps support the following basic operations:
To search for a given key value, |
https://en.wikipedia.org/wiki/Leonard%20Adleman | Leonard Adleman (born December 31, 1945) is an American computer scientist. He is one of the creators of the RSA encryption algorithm, for which he received the 2002 Turing Award. He is also known for the creation of the field of DNA computing.
Biography
Leonard M. Adleman was born to a Jewish family in California. His family had originally immigrated to the United States from modern-day Belarus, from the Minsk area. He grew up in San Francisco and attended the University of California, Berkeley, where he received his B.A. degree in mathematics in 1968 and his Ph.D. degree in EECS in 1976. He was also the mathematical consultant on the movie Sneakers. In 1996, he became a member of the National Academy of Engineering for contributions to the theory of computation and cryptography. He is also a member of the National Academy of Sciences.
Adleman is also an amateur boxer and has sparred with James Toney.
Discovery
In 1994, his paper Molecular Computation of Solutions To Combinatorial Problems described the experimental use of DNA as a computational system. In it, he solved a seven-node instance of the Hamiltonian Graph problem, an NP-complete problem similar to the travelling salesman problem. While the solution to a seven-node instance is trivial, this paper is the first known instance of the successful use of DNA to compute an algorithm. DNA computing has been shown to have potential as a means to solve several other large-scale combinatorial search problems. Adleman is widely referred to as the Father of DNA Computing.
In 2002, he and his research group managed to solve a 'nontrivial' problem using DNA computation. Specifically, they solved a 20-variable SAT problem having more than 1 million potential solutions. They did it in a manner similar to the one Adleman used in his seminal 1994 paper. First, a mixture of DNA strands logically representative of the problem's solution space was synthesized. This mixture was then operated upon algorithmically using biochemical techniques to winnow out the 'incorrect' strands, leaving behind only those strands that 'satisfied' the problem. Analysis of the nucleotide sequence of these remaining strands revealed 'correct' solutions to the original problem.
He is one of the original discoverers of the Adleman–Pomerance–Rumely primality test.
Fred Cohen, in his 1984 paper, Experiments with Computer Viruses credited Adleman with coining the term "computer virus".
As of 2017, Adleman is working on the mathematical theory of Strata. He is a Computer Science professor at the University of Southern California.
Awards
For his contribution to the invention of the RSA cryptosystem, Adleman, along with Ron Rivest and Adi Shamir, has been a recipient of the 1996 Paris Kanellakis Theory and Practice Award and the 2002 Turing Award, often called the Nobel Prize of Computer Science. Adleman was elected a Fellow of the American Academy of Arts and Sciences in 2006 and a 2021 ACM Fellow.
See also
List of |
https://en.wikipedia.org/wiki/Adleman | Adleman is a surname. Notable people with the surname include:
Leonard Adleman (born 1945), American theoretical computer scientist and professor of computer science and molecular biology
Robert H. Adleman (1919–1995), American novelist and historian
Tim Adleman (born 1987), American baseball player
See also
Adelman
Edelmann
References
Surnames of Jewish origin
Yiddish-language surnames |
https://en.wikipedia.org/wiki/Setun | Setun () was a computer developed in 1958 at Moscow State University. It was built under the leadership of Sergei Sobolev and Nikolay Brusentsov. It was the most modern ternary computer, using the balanced ternary numeral system and three-valued ternary logic instead of the two-valued binary logic prevalent in other computers.
Overview
The computer was built to fulfill the needs of Moscow State University. It was manufactured at the Kazan Mathematical plant. Fifty computers were built from 1959 until 1965, when production was halted. The characteristic operating memory consisted of 81 words of memory, each word composed of 18 trits (ternary digits) with additional 1944 words on magnetic drum (total of about 7 KB). Between 1965 and 1970, a regular binary computer was used at Moscow State University to replace it. Although this replacement binary computer performed equally well, it was 2.5 times the cost of the Setun.
In 1970, a new ternary computer architecture, the Setun-70, was developed. Edsger W. Dijkstra's ideas of structured programming were implemented in the hardware of this computer. The short instructions set was developed and implemented by Nikolay Brusentsov independently from RISC architecture principles.
The Setun-70 hardware architecture was transformed into the Dialogue System of Structured Programming (DSSP). DSSP emulates the "Setun 70" architecture on binary computers, thus it fulfills the advantages of structured programming. DSSP programming language has similar syntax to the Forth programming language but has a different sequence of base instructions, especially conditional jump instructions. DSSP was developed by Nikolay Brusentsov and doctoral students in the 1980s at Moscow State University. A 32-bit version was implemented in 1989.
See also
History of computing in the Soviet Union
References
Early computers
Soviet computer systems
Soviet inventions |
https://en.wikipedia.org/wiki/Molecular%20clock | The molecular clock is a figurative term for a technique that uses the mutation rate of biomolecules to deduce the time in prehistory when two or more life forms diverged. The biomolecular data used for such calculations are usually nucleotide sequences for DNA, RNA, or amino acid sequences for proteins. The benchmarks for determining the mutation rate are often fossil or archaeological dates. The molecular clock was first tested in 1962 on the hemoglobin protein variants of various animals, and is commonly used in molecular evolution to estimate times of speciation or radiation. It is sometimes called a gene clock or an evolutionary clock.
Early discovery and genetic equidistance
The notion of the existence of a so-called "molecular clock" was first attributed to Émile Zuckerkandl and Linus Pauling who, in 1962, noticed that the number of amino acid differences in hemoglobin between different lineages changes roughly linearly with time, as estimated from fossil evidence. They generalized this observation to assert that the rate of evolutionary change of any specified protein was approximately constant over time and over different lineages (known as the molecular clock hypothesis).
The genetic equidistance phenomenon was first noted in 1963 by Emanuel Margoliash, who wrote: "It appears that the number of residue differences between cytochrome c of any two species is mostly conditioned by the time elapsed since the lines of evolution leading to these two species originally diverged. If this is correct, the cytochrome c of all mammals should be equally different from the cytochrome c of all birds. Since fish diverges from the main stem of vertebrate evolution earlier than either birds or mammals, the cytochrome c of both mammals and birds should be equally different from the cytochrome c of fish. Similarly, all vertebrate cytochrome c should be equally different from the yeast protein." For example, the difference between the cytochrome c of a carp and a frog, turtle, chicken, rabbit, and horse is a very constant 13% to 14%. Similarly, the difference between the cytochrome c of a bacterium and yeast, wheat, moth, tuna, pigeon, and horse ranges from 64% to 69%. Together with the work of Emile Zuckerkandl and Linus Pauling, the genetic equidistance result led directly to the formal postulation of the molecular clock hypothesis in the early 1960s.
Similarly, Vincent Sarich and Allan Wilson in 1967 demonstrated that molecular differences among modern Primates in albumin proteins showed that approximately constant rates of change had occurred in all the lineages they assessed. The basic logic of their analysis involved recognizing that if one species lineage had evolved more quickly than a sister species lineage since their common ancestor, then the molecular differences between an outgroup (more distantly related) species and the faster-evolving species should be larger (since more molecular changes would have accumulated on that lineage) than the |
https://en.wikipedia.org/wiki/London%20and%20South%20Western%20Railway | The London and South Western Railway (LSWR, sometimes written L&SWR) was a railway company in England from 1838 to 1922. Originating as the London and Southampton Railway, its network extended to Dorchester and Weymouth, to Salisbury, Exeter and Plymouth, and to Padstow, Ilfracombe and Bude. It developed a network of routes in Hampshire, Surrey and Berkshire, including Portsmouth and Reading.
The LSWR became famous for its express passenger trains to Bournemouth and Weymouth, and to Devon and Cornwall. Nearer London it developed a dense suburban network and was pioneering in the introduction of a widespread suburban electrified passenger network. It was the prime mover of the development of Southampton Docks, which became an important ocean terminal as well as a harbour for cross channel services and for Isle of Wight ferries. Although the LSWR's area of influence was not the home of large-scale heavy industry, the transport of goods and mineral traffic was a major activity, and the company built a large marshalling yard at Feltham. Freight, docks and shipping business provided almost 40 per cent of turnover by 1908. The company handled the rebuilding of London Waterloo station as one of the great stations of the world, and the construction of the Waterloo & City line, giving access to the City of London. The main line was quadrupled and several of the junctions on it were given grade-separation. It pioneered the introduction of power signalling. In the Boer War its connections at Aldershot, Portland, and on Salisbury Plain, made it a vital part of the war effort, and later during the First World War it successfully handled the huge volume of traffic associated with bringing personnel, horses and equipment to the English channel ports, and the repatriation of the injured. It was a profitable company, paying a dividend of 5% or more from 1871.
Following the Railways Act 1921 the LSWR amalgamated with other railways to create the Southern Railway, on 1 January 1923, as part of the grouping of the railways. It was the largest constituent: it operated 862 route miles, and was involved in joint ventures that covered a further 157 miles. In passing its network to the new Southern Railway, it showed the way forward for long-distance travel and outer-suburban passenger operation, and for maritime activity. The network continued without much change through the lifetime of the Southern Railway, and for some years following nationalisation in 1948. In Devon and Cornwall the LSWR routes duplicated former Great Western Railway routes, and in the 1960s they were closed or substantially reduced in scope. Some unsuccessful rural branch lines nearer the home counties closed too in the 1960s and later, but much of the LSWR network continues in busy use to the present day.
The first main line
The London and South Western Railway arose out of the London and Southampton Railway (L&SR), which was promoted to connect Southampton to the capital; the company envisage |
https://en.wikipedia.org/wiki/Cos | Cos, COS, CoS, coS or Cos. may refer to:
Mathematics, science and technology
Carbonyl sulfide
Class of service (CoS or COS), a network header field defined by the IEEE 802.1p task group
Class of service (COS), a parameter in telephone systems
Cobalt sulfide
COS cells, cell lines COS-1 and COS-7
Cosine, a trigonometric function
Cosmic Origins Spectrograph, a Hubble Space Telescope instrument
Operating systems
COS (operating system), a Chinese mobile OS
Cray Operating System
Chippewa Operating System, from Control Data Corporation
Commercial Operating System, from Digital Equipment Corporation
GEC COS
Places
Cos, Ariège, France
Cos or Kos, a Greek island
COS, IATA code for Colorado Springs Airport, Colorado, US
Colorado Springs, Colorado, a US city, derived from its airport's code
Gulf of Cos, Aegean Sea
Villa de Cos, Zacatecas, Mexico
Cosio Valtellino (Cös), Lombardy, Italy
COS, UNDP country code of Costa Rica
Organizations, societies and churches
Charity Organization Society
Children's Orchestra Society, New York City, US
Church of Satan, a religious organization
Church of Scientology
Church of Scotland
Commandement des Opérations Spéciales, coordinating French special forces
Community of Science, an online database
Company of Servers, Anglican altar servers
Cooper Ornithological Society, California, US
Universities and schools
College of the Sequoias, California, US
College of the Siskiyous, California, US
Other uses
Childhood onset schizophrenia
Roman consul, a political office in Ancient Rome
COS, a British fashion brand
Cos lettuce
Martín Perfecto de Cos (1800–1854), Mexican general
Consequence of Sound (now Consequence), a New York, US online magazine
Cos (television series), 1976, hosted by Bill Cosby
Space Operations Command (Italy) (Comando delle Operazioni Spaziali)
See also
Kos (disambiguation) |
https://en.wikipedia.org/wiki/Shading | Shading refers to the depiction of depth perception in 3D models (within the field of 3D computer graphics) or illustrations (in visual art) by varying the level of darkness. Shading tries to approximate local behavior of light on the object's surface and is not to be confused with techniques of adding shadows, such as shadow mapping or shadow volumes, which fall under global behavior of light.
In drawing
Shading is used traditionally in drawing for depicting a range of darkness by applying media more densely or with a darker shade for darker areas, and less densely or with a lighter shade for lighter areas. Light patterns, such as objects having light and shaded areas, help when creating the illusion of depth on paper.
There are various techniques of shading, including cross hatching, where perpendicular lines of varying closeness are drawn in a grid pattern to shade an area. The closer the lines are together, the darker the area appears. Likewise, the farther apart the lines are, the lighter the area appears.
Powder shading is a sketching shading method. In this style, stumping powder and paper stumps are used to draw a picture. (This can be in color.) The stumping powder is smooth and doesn't have any shiny particles. The paper to be used should have small grains on it so that the powder remains on the paper.
In computer graphics
In computer graphics, shading refers to the process of altering the color of an object/surface/polygon in the 3D scene, based on things like (but not limited to) the surface's angle to lights, its distance from lights, its angle to the camera and material properties (e.g. bidirectional reflectance distribution function) to create a photorealistic effect.
Shading is performed during the rendering process by a program called a shader.
Surface angle to a light source
Shading alters the colors of faces in a 3D model based on the angle of the surface to a light source or light sources.
The first image below has the faces of the box rendered, but all in the same color. Edge lines have been rendered here as well which makes the image easier to see.
The second image is the same model rendered without edge lines. It is difficult to tell where one face of the box ends and the next begins.
The third image has shading enabled, which makes the image more realistic and makes it easier to see which face is which.
Types of lighting
When a shader computes the result color, it uses a lighting model to determine the amount of light reflected at specific points on the surface. Different lighting models can be combined with different shading techniques — while lighting says how much light is reflected, shading determines how this information is used in order to compute the final result. It may for example compute lighting only at specific points and use interpolation to fill in the rest. The shader may also decide about how many light sources to take into account etc.
Ambient lighting
An ambient light source represents an om |
https://en.wikipedia.org/wiki/Demarcation%20point | In telephony, the demarcation point is the point at which the public switched telephone network ends and connects with the customer's on-premises wiring. It is the dividing line which determines who is responsible for installation and maintenance of wiring and equipment—customer/subscriber, or telephone company/provider. The demarcation point varies between countries and has changed over time.
Demarcation point is sometimes abbreviated as demarc, DMARC, or similar. The term MPOE (minimum or main point of entry) is synonymous, with the added implication that it occurs as soon as possible upon entering the customer premises. A network interface device often serves as the demarcation point.
History
Prior to Federal Communications Commission (FCC) regulations separating the ownership of customer premises telecommunication equipment from the telephone network, there was no need for a public standard governing the interconnection of customer premises equipment (CPE) to the United States' telephone network, since both the devices and the “local loop” wiring to the central office were owned and maintained by the local telephone company.
Concurrent with the transfer of existing "embedded" CPE to the customer (customers could buy new telephones at retail or could continue to lease their existing equipment from the company), it was necessary to provide a standardized way to connect equipment, and also provide a way to test the phone company's service separately from the customer's equipment.
The ability of customers to buy and maintain their CPE and attach it to the network was stimulated by lawsuits by equipment manufacturers, such as the Hush-a-Phone v. FCC suit. Additionally, computer companies’ ability to offer enhanced services to customers was likewise constrained by the telephone companies’ control of all devices connected to the network. As the Bell telephone companies were themselves restricted from offering such enhanced services, there was little momentum to advance the state of the art.
The newly developed equipment-network separation was codified in Part 68 of the Code of Federal Regulations in the United States and later in comparable regulatory standards in other countries.
The physical and electrical interconnection is called the demarcation point, or Demarc, which includes one or more customer-accessible jack interfaces; previously, the interface was typically hard-wired and often in a telephone company-owned locked enclosure.
The premises-vs.-network separation in the United States, insofar as it affected the former Bell System, was independent of AT&T's divestiture of the local telephone companies on January 1, 1984. However, CPE interconnection and Bell System divestiture were part of a larger restructuring of the domestic telecommunications industry which took place during the 1980s and are commonly, if inaccurately, seen as one event. The historical Bell System domination of the United States telecommunications industry was |
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