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Switching Circuit Theory
Switching circuit theory is the mathematical study of the properties of networks of idealized switches. Such networks may be strictly combinational logic, in which their output state is only a function of the present state of their inputs; or may also contain sequential elements, where the present state depends on the present state and past states; in that sense, sequential circuits are said to include "memory" of past states. An important class of sequential circuits are state machines. Switching circuit theory is applicable to the design of telephone systems, computers, and similar systems. Switching circuit theory provided the mathematical foundations and tools for digital system design in almost all areas of modern technology. In an 1886 letter, Charles Sanders Peirce described how logical operations could be carried out by electrical switching circuits. During 1880–1881 he showed that NOR gates alone (or alternatively NAND gates alone) can be used to reproduce the func ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combinational Logic
In automata theory, combinational logic (also referred to as time-independent logic) is a type of digital logic that is implemented by Boolean circuits, where the output is a pure function of the present input only. This is in contrast to sequential logic, in which the output depends not only on the present input but also on the history of the input. In other words, sequential logic has ''memory'' while combinational logic does not. Combinational logic is used in computer circuits to perform Boolean algebra on input signals and on stored data. Practical computer circuits normally contain a mixture of combinational and sequential logic. For example, the part of an arithmetic logic unit, or ALU, that does mathematical calculations is constructed using combinational logic. Other circuits used in computers, such as half adders, full adders, half subtractors, full subtractors, multiplexers, demultiplexers, encoders and decoders are also made by using combinational logic. Prac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tractatus Logico-Philosophicus
The ''Tractatus Logico-Philosophicus'' (widely abbreviated and Citation, cited as TLP) is the only book-length philosophical work by the Austrian philosopher Ludwig Wittgenstein that was published during his lifetime. The project had a broad goal: to identify the relationship between language and reality, and to define the limits of science. Wittgenstein wrote the notes for the ''Tractatus'' while he was a soldier during World War I and completed it during a military leave in the summer of 1918. It was originally published in German in 1921 as ''Logisch-Philosophische Abhandlung'' (Logical-Philosophical Treatise). In 1922 it was published together with an English translation and a Latin title, which was suggested by G. E. Moore as homage to Baruch Spinoza's ''Tractatus Theologico-Politicus'' (1670). The ''Tractatus'' is written in an austere and succinct literary style, containing almost no arguments as such, but consists of 525 declarative statements altogether, which are hierarc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Message Switching
In telecommunications, message switching involves messages routed in their entirety, one hop at a time. It evolved from circuit switching and was the precursor of packet switching. An example of message switching is email in which the message is sent through different intermediate servers to reach the mail server for storing. Unlike packet switching, the message is not divided into smaller units and sent independently over the network. History Western Union operated a message switching system, Plan 55-A, for processing telegrams in the 1950s. Leonard Kleinrock wrote a doctoral thesis at the Massachusetts Institute of Technology in 1962 that analyzed queueing delays in this system. Message switching was built by Collins Radio Company, Newport Beach, California, during the period 1959–1963 for sale to large airlines, banks and railroads. The original design for the ARPANET was Wesley Clark's April 1967 proposal for using Interface Message Processors to create a message ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circuit Switching
Circuit switching is a method of implementing a telecommunications network in which two network nodes establish a dedicated communications channel ( circuit) through the network before the nodes may communicate. The circuit guarantees the full bandwidth of the channel and remains connected for the duration of the communication session. The circuit functions as if the nodes were physically connected as with an electrical circuit. Circuit switching originated in analog telephone networks where the network created a dedicated circuit between two telephones for the duration of a telephone call. It contrasts with message switching and packet switching used in modern digital networks in which the trunklines between switching centres carry data between many different nodes in the form of data packets without dedicated circuits. Description The defining example of a circuit-switched network is the early analogue telephone network. When a call is made from one telephone to ano ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Race Condition
A race condition or race hazard is the condition of an electronics, software, or other system where the system's substantive behavior is dependent on the sequence or timing of other uncontrollable events, leading to unexpected or inconsistent results. It becomes a bug when one or more of the possible behaviors is undesirable. The term ''race condition'' was already in use by 1954, for example in David A. Huffman's doctoral thesis "The synthesis of sequential switching circuits". Race conditions can occur especially in logic circuits or multithreaded or distributed software programs. Using mutual exclusion can prevent race conditions in distributed software systems. In electronics A typical example of a race condition may occur when a logic gate combines signals that have traveled along different paths from the same source. The inputs to the gate can change at slightly different times in response to a change in the source signal. The output may, for a brief period, chan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hazard (logic)
In digital logic, a hazard is an undesirable effect caused by either a deficiency in the system or external influences in both synchronous circuit, synchronous and asynchronous circuits. Logic hazards are manifestations of a problem in which changes in the input variables do not change the output correctly due to some form of delay caused by logic elements (NOT gate, NOT, AND gate, AND, OR gates, etc.) This results in the logic not performing its function properly. The three different most common kinds of hazards are usually referred to as static, dynamic and function hazards. Hazards are a temporary problem, as the logic circuit will eventually settle to the desired function. Therefore, in synchronous designs, it is standard practice to flip-flop (electronics), register the output of a circuit before it is being used in a different clock domain or routed out of the system, so that hazards do not cause any problems. If that is not the case, however, it is imperative that hazard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-element Boolean Algebra
In mathematics and abstract algebra, the two-element Boolean algebra is the Boolean algebra whose ''underlying set'' (or universe or ''carrier'') ''B'' is the Boolean domain. The elements of the Boolean domain are 1 and 0 by convention, so that ''B'' = . Paul Halmos's name for this algebra "2" has some following in the literature, and will be employed here. Definition ''B'' is a partially ordered set and the elements of ''B'' are also its bounds. An operation of arity ''n'' is a mapping from ''B''n to ''B''. Boolean algebra consists of two binary operations and unary complementation. The binary operations have been named and notated in various ways. Here they are called 'sum' and 'product', and notated by infix '+' and '∙', respectively. Sum and product commute and associate, as in the usual algebra of real numbers. As for the order of operations, brackets are decisive if present. Otherwise '∙' precedes '+'. Hence is parsed as and not as . Complementation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Victor Shestakov
Victor Ivanovich Shestakov (Russian: ) (1907–1987) was a Russian/Soviet logician and theoretician of electrical engineering. In 1935 he discovered the possible interpretation of Boolean algebra of logic in electro-mechanical relay circuits. He graduated from Moscow State University (1934) and worked there in the General Physics Department almost until his death. Shestakov proposed a theory of electric switches based on Boolean logic earlier than Claude Shannon (according to certification of Soviet logicians and mathematicians Sofya Yanovskaya, M. G. Gaaze-Rapoport, Roland Dobrushin, Oleg Lupanov, Yu. A. Gastev, Yu. T. Medvedev, and Vladimir Andreevich Uspensky). However, both Shestakov and Shannon defended their theses the same year (1938), and the first publication of Shestakov's result took place only in 1941 (in Russian). In the early 20th century, relay circuits began to be more widely used in automatics, defense of electric and communications systems. Every relay circui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Claude Shannon
Claude Elwood Shannon (April 30, 1916 – February 24, 2001) was an American mathematician, electrical engineer, computer scientist, cryptographer and inventor known as the "father of information theory" and the man who laid the foundations of the Information Age. Shannon was the first to describe the use of Boolean algebra—essential to all digital electronic circuits—and helped found artificial intelligence (AI). Roboticist Rodney Brooks declared Shannon the 20th century engineer who contributed the most to 21st century technologies, and mathematician Solomon W. Golomb described his intellectual achievement as "one of the greatest of the twentieth century". At the University of Michigan, Shannon dual degreed, graduating with a Bachelor of Science in electrical engineering and another in mathematics, both in 1936. A 21-year-old master's degree student in electrical engineering at MIT, his thesis, "A Symbolic Analysis of Relay and Switching Circuits", demonstrated that electric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Akira Nakashima
Akira Nakashima (中嶋 章 or 中島 章, also written as ''Nakashima Akira'', ''Nakasima Akira'' or ''Nakajima Akira'', 5 January 1908 – 29 October 1970) was a Japanese electrical engineer of the NEC. He got a bachelor's degree in electrical engineering from the Imperial University of Tokyo. Akira Nakashima independenly introduced switching circuit theory in papers from 1934 to 1936, concurrent with Victor Shestakov and Claude Shannon, laying the foundations for digital circuit design, in digital computer A computer is a machine that can be programmed to automatically carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic sets of operations known as ''programs'', wh ...s and other areas of modern technology. However, Shannon's ideas were markedly different in approach and theoretical framework compared to the work of Nakashima, whose work was still based on the existent circuit theory of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Z1 (computer)
The Z1 was a motor-driven mechanical computer designed by German inventor Konrad Zuse from 1936 to 1937, which he built in his parents' home from 1936 to 1938. It was a binary, electrically driven, mechanical calculator, with limited programmability, reading instructions from punched celluloid film. The “Z1” was the first freely programmable computer in the world that used Boolean logic and binary floating-point numbers; however, it was unreliable in operation. It was completed in 1938 and financed completely by private funds. This computer was destroyed in the bombardment of Berlin in December 1943, during World War II, together with all construction plans. The Z1 was the first in a series of computers that Zuse designed. Its original name was "V1" for Versuchsmodell 1 (meaning Experimental Model 1). After WW2, it was renamed "Z1" to differentiate it from the flying bombs designed by Robert Lusser. The Z2 and Z3 were follow-ups based on many of the same ideas as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Konrad Zuse
Konrad Ernst Otto Zuse (; ; 22 June 1910 – 18 December 1995) was a German civil engineer, List of pioneers in computer science, pioneering computer scientist, inventor and businessman. His greatest achievement was the world's first programmable computer; the functional program-controlled Turing completeness, Turing-complete Z3 (computer), Z3 became operational in May 1941. Thanks to this machine and its predecessors, Zuse is regarded by some as the inventor and father of the modern computer. Zuse was noted for the S2 computing machine, considered the first process control computer. In 1941, he founded one of the earliest computer businesses, producing the Z4 (computer), Z4, which became the world's first commercial computer. From 1943 to 1945 he designed Plankalkül, the first high-level programming language. In 1969, Zuse suggested the concept of a digital physics, computation-based universe in his book (''Calculating Space''). Much of his early work was financed by his f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
