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Temporal Logic Of Actions
Temporal logic of actions (TLA) is a logic developed by Leslie Lamport, which combines temporal logic with a logic of actions. It is used to describe behaviours of concurrent and distributed systems. It is the logic underlying the specification language TLA+. Details Statements in the temporal logic of actions are of the form t, where ''A'' is an action and ''t'' contains a subset of the variables appearing in ''A''. An action is an expression containing primed and non-primed variables, such as x+x'*y=y'. The meaning of the non-primed variables is ''the variable's value in this state''. The meaning of primed variables is ''the variable's value in the next state''. The above expression means the value of ''x'' ''today'', plus the value of ''x'' ''tomorrow'' times the value of ''y'' ''today'', equals the value of ''y'' ''tomorrow''. The meaning of t is that either ''A'' is valid now, or the variables appearing in ''t'' do not change. This allows for stuttering steps, in which n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leslie Lamport
Leslie B. Lamport (born February 7, 1941 in Brooklyn) is an American computer scientist and mathematician. Lamport is best known for his seminal work in distributed systems, and as the initial developer of the document preparation system LaTeX and the author of its first manual. Lamport was the winner of the 2013 Turing Award for imposing clear, well-defined coherence on the seemingly chaotic behavior of distributed computing systems, in which several autonomous computers communicate with each other by passing messages. He devised important algorithms and developed formal modeling and verification protocols that improve the quality of real distributed systems. These contributions have resulted in improved correctness, performance, and reliability of computer systems. Early life and education Lamport was born into a Jewish family in Brooklyn, New York, the son of Benjamin and Hannah Lamport (née Lasser). His father was an immigrant from Volkovisk in the Russian Empire (now Vawk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Logic
In logic, temporal logic is any system of rules and symbolism for representing, and reasoning about, propositions qualified in terms of time (for example, "I am ''always'' hungry", "I will ''eventually'' be hungry", or "I will be hungry ''until'' I eat something"). It is sometimes also used to refer to tense logic, a modal logic-based system of temporal logic introduced by Arthur Prior in the late 1950s, with important contributions by Hans Kamp. It has been further developed by computer scientists, notably Amir Pnueli, and logicians. Temporal logic has found an important application in formal verification, where it is used to state requirements of hardware or software systems. For instance, one may wish to say that ''whenever'' a request is made, access to a resource is ''eventually'' granted, but it is ''never'' granted to two requestors simultaneously. Such a statement can conveniently be expressed in a temporal logic. Motivation Consider the statement "I am hungry". Though it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logic Of Action
Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or of logical truths. It is a formal science investigating how conclusions follow from premises in a topic-neutral way. When used as a countable noun, the term "a logic" refers to a logical formal system that articulates a proof system. Formal logic contrasts with informal logic, which is associated with informal fallacies, critical thinking, and argumentation theory. While there is no general agreement on how formal and informal logic are to be distinguished, one prominent approach associates their difference with whether the studied arguments are expressed in formal or informal languages. Logic plays a central role in multiple fields, such as philosophy, mathematics, computer science, and linguistics. Logic studies arguments, which consist of a set of premises together with a conclusion. Premises and conclusions are usually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concurrency (computer Science)
In computer science, concurrency is the ability of different parts or units of a program, algorithm, or problem to be executed out-of-order or in partial order, without affecting the outcome. This allows for parallel execution of the concurrent units, which can significantly improve overall speed of the execution in multi-processor and multi-core systems. In more technical terms, concurrency refers to the decomposability of a program, algorithm, or problem into order-independent or partially-ordered components or units of computation. According to Rob Pike, concurrency is the composition of independently executing computations, and concurrency is not parallelism: concurrency is about dealing with lots of things at once but parallelism is about doing lots of things at once. Concurrency is about structure, parallelism is about execution, concurrency provides a way to structure a solution to solve a problem that may (but not necessarily) be parallelizable. A number of mathem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributed Computing
A distributed system is a system whose components are located on different networked computers, which communicate and coordinate their actions by passing messages to one another from any system. Distributed computing is a field of computer science that studies distributed systems. The components of a distributed system interact with one another in order to achieve a common goal. Three significant challenges of distributed systems are: maintaining concurrency of components, overcoming the lack of a global clock, and managing the independent failure of components. When a component of one system fails, the entire system does not fail. Examples of distributed systems vary from SOA-based systems to massively multiplayer online games to peer-to-peer applications. A computer program that runs within a distributed system is called a distributed program, and ''distributed programming'' is the process of writing such programs. There are many different types of implementations for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TLA+
TLA+ is a formal specification language developed by Leslie Lamport. It is used for designing, modelling, documentation, and verification of programs, especially concurrent systems and distributed systems. TLA+ is considered to be exhaustively-testable pseudocode, and its use likened to drawing blueprints for software systems; ''TLA'' is an acronym for Temporal Logic of Actions. For design and documentation, TLA+ fulfills the same purpose as informal technical specifications. However, TLA+ specifications are written in a formal language of logic and mathematics, and the precision of specifications written in this language is intended to uncover design flaws before system implementation is underway. Since TLA+ specifications are written in a formal language, they are amenable to finite model checking. The model checker finds all possible system behaviours up to some number of execution steps, and examines them for violations of desired invariance properties such as safety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Logic (modal Logic)
In logic, philosophy, and theoretical computer science, dynamic logic is an extension of modal logic capable of encoding properties of computer programs. A simple example of a statement in dynamic logic is :\text \to text\text, which states that if the ground is currently dry and it rains, then afterwards the ground will be wet. The syntax of dynamic logic contains a language of ''propositions'' (like "the ground is dry") and a language of ''actions'' (like "it rains"). The core modal constructs are , which states that after performing action ''a'' the proposition ''p'' should hold, and \langle a \rangle p, which states that after performing action ''a'' it is possible that ''p'' holds. The action language supports operations a\mathbinb (doing one action followed by another), a \cup b (doing one action or another), and iteration a (doing one action zero or more times). The proposition language supports Boolean operations (and, or, and not). The action logic is expressive enough ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Logic
In logic, temporal logic is any system of rules and symbolism for representing, and reasoning about, propositions qualified in terms of time (for example, "I am ''always'' hungry", "I will ''eventually'' be hungry", or "I will be hungry ''until'' I eat something"). It is sometimes also used to refer to tense logic, a modal logic-based system of temporal logic introduced by Arthur Prior in the late 1950s, with important contributions by Hans Kamp. It has been further developed by computer scientists, notably Amir Pnueli, and logicians. Temporal logic has found an important application in formal verification, where it is used to state requirements of hardware or software systems. For instance, one may wish to say that ''whenever'' a request is made, access to a resource is ''eventually'' granted, but it is ''never'' granted to two requestors simultaneously. Such a statement can conveniently be expressed in a temporal logic. Motivation Consider the statement "I am hungry". Though it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PlusCal
PlusCal (formerly called +CAL) is a formal specification language created by Leslie Lamport, which transpiles to TLA+. In contrast to TLA+'s action-oriented focus on distributed systems, PlusCal most resembles an imperative programming language and is better-suited when specifying sequential algorithm In computer science, a sequential algorithm or serial algorithm is an algorithm that is executed sequentially – once through, from start to finish, without other processing executing – as opposed to concurrently or in parallel. The term is prim ...s. PlusCal was designed to replace pseudocode, retaining its simplicity while providing a formally-defined and verifiable language. A one-bit clock is written in PlusCal as follows: -- fair algorithm OneBitClock See also * TLA+ * Pseudocode References External links * PlusCal tools and documentation are found on thPlusCal Algorithm Language page Formal methods Formal specification languages Algorithm descripti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
INRIA
The National Institute for Research in Digital Science and Technology (Inria) () is a French national research institution focusing on computer science and applied mathematics. It was created under the name ''Institut de recherche en informatique et en automatique'' (IRIA) in 1967 at Rocquencourt near Paris, part of Plan Calcul. Its first site was the historical premises of SHAPE (central command of NATO military forces), which is still used as Inria's main headquarters. In 1980, IRIA became INRIA. Since 2011, it has been styled ''Inria''. Inria is a Public Scientific and Technical Research Establishment (EPST) under the double supervision of the French Ministry of National Education, Advanced Instruction and Research and the Ministry of Economy, Finance and Industry. Administrative status Inria has 9 research centers distributed across France (in Bordeaux, Grenoble- Inovallée, Lille, Lyon, Nancy, Paris-Rocquencourt, Rennes, Saclay, and Sophia Antipolis) and one center ab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Build (developer Conference)
Microsoft Build (often stylised as ) is an annual conference event held by Microsoft, aimed at software engineers and web developers using Windows, Microsoft Azure and other Microsoft technologies. First held in 2011, it serves as a successor for Microsoft's previous developer events, the Professional Developers Conference (an infrequent event which covered development of software for the Windows operating system) and MIX (which covered web development centering on Microsoft technology such as Silverlight and ASP.net). The attendee price was (US)$2,195 in 2016, up from $2,095 in 2015. It sold out quickly, within one minute of the registration site opening in 2016. Format The event has been held at a large convention center, or purpose-built meeting space on the Microsoft Campus. The Keynote on the first day has been led by the Microsoft CEO addressing the press and developers. It has been the place to announce the general technology milestones for developers. There are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
