|
Dining Philosophers Problem
In computer science, the dining philosophers problem is an example problem often used in concurrent algorithm design to illustrate synchronization issues and techniques for resolving them. It was originally formulated in 1965 by Edsger Dijkstra as a student exam exercise, presented in terms of computers competing for access to tape drive peripherals. Soon after, Tony Hoare gave the problem its present form. Problem statement Five philosophers dine together at the same table. Each philosopher has their own place at the table. There is a fork between each plate. The dish served is a kind of spaghetti which has to be eaten with two forks. Each philosopher can only alternately think and eat. Moreover, a philosopher can only eat their spaghetti when they have both a left and right fork. Thus two forks will only be available when their two nearest neighbors are thinking, not eating. After an individual philosopher finishes eating, they will put down both forks. The problem is how to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
An Illustration Of The Dining Philosophers Problem
An, AN, aN, or an may refer to: Businesses and organizations * Airlinair (IATA airline code AN) * Alleanza Nazionale, a former political party in Italy * AnimeNEXT, an annual anime convention located in New Jersey * Anime North, a Canadian anime convention * Ansett Australia, a major Australian airline group that is now defunct (IATA designator AN) * Apalachicola Northern Railroad (reporting mark AN) 1903–2002 ** AN Railway, a successor company, 2002– * Aryan Nations, a white supremacist religious organization * Australian National Railways Commission, an Australian rail operator from 1975 until 1987 * Antonov, a Ukrainian (formerly Soviet) aircraft manufacturing and services company, as a model prefix Entertainment and media * Antv, an Indonesian television network * '' Astronomische Nachrichten'', or ''Astronomical Notes'', an international astronomy journal * ''Avisa Nordland'', a Norwegian newspaper * ''Sweet Bean'' (あん), a 2015 Japanese film also known as ''An ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
State Variable
A state variable is one of the set of variables that are used to describe the mathematical "state" of a dynamical system. Intuitively, the state of a system describes enough about the system to determine its future behaviour in the absence of any external forces affecting the system. Models that consist of coupled first-order differential equations are said to be in state-variable form. Examples *In mechanical systems, the position coordinates and velocities of mechanical parts are typical state variables; knowing these, it is possible to determine the future state of the objects in the system. *In thermodynamics, a state variable is an independent variable of a state function. Examples include internal energy, enthalpy, temperature, pressure, volume and entropy. Heat and work are not state functions, but process functions. *In electronic/electrical circuits, the voltages of the nodes and the currents through components in the circuit are usually the state variables. In any el ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1965 Introductions
Events January–February * January 14 – The Prime Minister of Northern Ireland and the Taoiseach of the Republic of Ireland meet for the first time in 43 years. * January 20 ** Lyndon B. Johnson is Second inauguration of Lyndon B. Johnson, sworn in for a full term as President of the United States. ** Indonesian President Sukarno announces the withdrawal of the Indonesian government from the United Nations. * January 30 – The Death and state funeral of Winston Churchill, state funeral of Sir Winston Churchill takes place in London with the largest assembly of dignitaries in the world until the 2005 funeral of Pope John Paul II. * February 4 – Trofim Lysenko is removed from his post as director of the Institute of Genetics at the Russian Academy of Sciences, Academy of Sciences in the Soviet Union. Lysenkoism, Lysenkoist theories are now treated as pseudoscience. * February 12 ** The African and Malagasy Republic, Malagasy Common Organization ('; OCA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter H
Peter may refer to: People * List of people named Peter, a list of people and fictional characters with the given name * Peter (given name) ** Saint Peter (died 60s), apostle of Jesus, leader of the early Christian Church * Peter (surname), a surname (including a list of people with the name) Culture * Peter (actor) (born 1952), stage name Shinnosuke Ikehata, Japanese dancer and actor * Peter (album), ''Peter'' (album), a 1993 EP by Canadian band Eric's Trip * Peter (1934 film), ''Peter'' (1934 film), a 1934 film directed by Henry Koster *Peter (2021 film), ''Peter'' (2021 film), Marathi language film * Peter (Fringe episode), "Peter" (''Fringe'' episode), an episode of the television series ''Fringe'' * Peter (novel), ''Peter'' (novel), a 1908 book by Francis Hopkinson Smith * Peter (short story), "Peter" (short story), an 1892 short story by Willa Cather Animals * Peter, the Lord's cat, cat at Lord's Cricket Ground in London * Peter (chief mouser), Chief Mouser between 1929 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
POPL
The annual ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages (POPL) is an academic conference in the field of computer science, with focus on fundamental principles in the design, definition, analysis, and implementation of programming languages, programming systems, and programming interfaces. The venue is jointly sponsored by two Special Interest Groups of the Association for Computing Machinery: SIGPLAN and SIGACT. POPL ranks as A* (top 4%) in the CORE conference ranking. The proceedings of the conference are hosted at the ACM Digital Library. They were initially under a paywall, but since 2017 they are published in open access as part of the journal ''Proceedings of the ACM on Programming Languages'' (PACMPL). Affiliated events * Declarative Aspects of Multicore Programming (DAMP) * Foundations and Developments of Object-Oriented Languages (FOOL/WOOD) * Partial Evaluation and Semantics-Based Program Manipulation (PEPM) * Practical Applications of Decl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sleeping Barber Problem
In computer science, the sleeping barber problem is a classic inter-process communication and synchronization problem that illustrates the complexities that arise when there are multiple operating system processes. The problem was originally proposed in 1965 by computer science pioneer Edsger Dijkstra, who used it to make the point that general semaphores are often superfluous. Problem statement Imagine a hypothetical barbershop with one barber, one barber chair, and a waiting room with ''n'' chairs (''n'' may be 0) for waiting customers. The following rules apply: * If there are no customers, the barber falls asleep in the chair * A customer must wake the barber if he is asleep * If a customer arrives while the barber is working, the customer leaves if all chairs are occupied and sits in an empty chair if it's available * When the barber finishes a haircut, he inspects the waiting room to see if there are any waiting customers and falls asleep if there are none There are two m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cigarette Smokers Problem
The cigarette smokers problem is a concurrency problem in computer science, originally described in 1971 by Suhas Patil. The problem has been criticized for having "restrictions which cannot be justified by practical considerations." Problem description Patil's problem includes a "quite arbitrary" "restriction that the process which supplies the ingredients cannot be changed and that no conditional statements may be used." Assume a cigarette requires three ingredients to make and smoke: tobacco, paper, and matches. There are three smokers around a table, each of whom has an infinite supply of ''one'' of the three ingredients — one smoker has an infinite supply of tobacco, another has paper, and the third has matches. There is also a non-smoking agent who enables the smokers to make their cigarettes by arbitrarily ( non-deterministically) selecting two of the supplies to place on the table. The smoker who has the third supply should remove the two items from the table, us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Directed Acyclic Graph
In mathematics, particularly graph theory, and computer science, a directed acyclic graph (DAG) is a directed graph with no directed cycles. That is, it consists of vertices and edges (also called ''arcs''), with each edge directed from one vertex to another, such that following those directions will never form a closed loop. A directed graph is a DAG if and only if it can be topologically ordered, by arranging the vertices as a linear ordering that is consistent with all edge directions. DAGs have numerous scientific and computational applications, ranging from biology (evolution, family trees, epidemiology) to information science (citation networks) to computation (scheduling). Directed acyclic graphs are sometimes instead called acyclic directed graphs or acyclic digraphs. Definitions A graph is formed by vertices and by edges connecting pairs of vertices, where the vertices can be any kind of object that is connected in pairs by edges. In the case of a directed graph, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jayadev Misra
Jayadev Misra is an Indian-born computer scientist who has spent most of his professional career in the United States. He is the Schlumberger Centennial Chair Emeritus in computer science and a University Distinguished Teaching Professor Emeritus at the University of Texas at Austin. Professionally he is known for his contributions to the formal aspects of concurrent programming and for jointly spearheading, with Sir Tony Hoare, the project on Verified Software Initiative (VSI). Education and early career Misra received a B.Tech. in electrical engineering from IIT Kanpur, India in 1969 and a Ph.D. in electrical engineering and computer science from the Johns Hopkins University, Baltimore, Maryland in 1972. After a brief period working for IBM, he joined the University of Texas at Austin in 1974 where he has remained throughout his career, except for a sabbatical year spent at Stanford University during 1983–1984. He retired from active teaching in 2015. Major professional c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pearson PLC
Pearson plc is a British multinational corporation, multinational publishing and education company headquartered in London, England. It was founded as a construction business in the 1840s but switched to publishing in the 1920s.J. A. Spender, Spender, J. A., ''Weetman Pearson: First Viscount Cowdray'' (London: Cassell (publisher), Cassell and Company Limited, 1930). It is the largest education company and was once the largest book publisher in the world. In 2013 Pearson merged its Penguin Books with German conglomerate Bertelsmann. In 2015, the company announced a change to focus solely on education. Pearson plc owns one of the GCSE Examination boards in the United Kingdom, examining boards for the UK, Edexcel. Pearson has a primary listing on the London Stock Exchange and is a constituent of the FTSE 100 Index. It has a secondary listing on the New York Stock Exchange in the form of American depositary receipts. History Construction business: 1844 to the 1920s The comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
