|
Actor Model Middle History
In computer science, the Actor model, first published in 1973 , is a mathematical model of concurrent computation. This article reports on the middle history of the Actor model in which major themes were initial implementations, initial applications, and development of the first proof theory and denotational model. It is the follow on article to Actor model early history which reports on the early history of the Actor model which concerned the basic development of the concepts. The article Actor model later history reports on developments after the ones reported in this article. Proving properties of Actor systems Carl Hewitt 974published the principle of Actor induction which is: #Suppose that an Actor has property when it is created #Further suppose that if has property when it processes a message, then it has property when it processes the next message. #Then always has the property . In his doctoral dissertation, Aki Yonezawa developed further techniques for provin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Science
Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to Applied science, practical disciplines (including the design and implementation of Computer architecture, hardware and Computer programming, software). Computer science is generally considered an area of research, academic research and distinct from computer programming. Algorithms and data structures are central to computer science. The theory of computation concerns abstract models of computation and general classes of computational problem, problems that can be solved using them. The fields of cryptography and computer security involve studying the means for secure communication and for preventing Vulnerability (computing), security vulnerabilities. Computer graphics (computer science), Computer graphics and computational geometry address the generation of images. Progr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actor Model
The actor model in computer science is a mathematical model of concurrent computation that treats ''actor'' as the universal primitive of concurrent computation. In response to a message it receives, an actor can: make local decisions, create more actors, send more messages, and determine how to respond to the next message received. Actors may modify their own private state, but can only affect each other indirectly through messaging (removing the need for lock-based synchronization). The actor model originated in 1973. It has been used both as a framework for a theoretical understanding of computation and as the theoretical basis for several practical implementations of concurrent systems. The relationship of the model to other work is discussed in actor model and process calculi. History According to Carl Hewitt, unlike previous models of computation, the actor model was inspired by physics, including general relativity and quantum mechanics. It was also influenced by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concurrent Computation
Concurrent computing is a form of computing in which several computations are executed '' concurrently''—during overlapping time periods—instead of ''sequentially—''with one completing before the next starts. This is a property of a system—whether a program, computer, or a network—where there is a separate execution point or "thread of control" for each process. A ''concurrent system'' is one where a computation can advance without waiting for all other computations to complete. Concurrent computing is a form of modular programming. In its paradigm an overall computation is factored into subcomputations that may be executed concurrently. Pioneers in the field of concurrent computing include Edsger Dijkstra, Per Brinch Hansen, and C.A.R. Hoare. Introduction The concept of concurrent computing is frequently confused with the related but distinct concept of parallel computing, Pike, Rob (2012-01-11). "Concurrency is not Parallelism". ''Waza conference'', 11 January ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actor Model Early History
In computer science, the Actor model, first published in 1973, is a mathematical model of concurrent computation. Event orderings versus global state A fundamental challenge in defining the Actor model is that it did not provide for global states so that a computational step could not be defined as going from one global state to the next global state as had been done in all previous models of computation. In 1963 in the field of Artificial Intelligence, John McCarthy introduced situation variables in logic in the Situational Calculus. In McCarthy and Hayes 1969, a situation is defined as "the complete state of the universe at an instant of time." In this respect, the situations of McCarthy are not suitable for use in the Actor model since it has no global states. From the definition of an Actor, it can be seen that numerous events take place: local decisions, creating Actors, sending messages, receiving messages, and designating how to respond to the next message received. Partia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actor Model Later History
In computer science, the Actor model, first published in 1973 , is a mathematical model of concurrent computation. This article reports on the later history of the Actor model in which major themes were investigation of the basic power of the model, study of issues of compositionality, development of architectures, and application to Open systems. It is the follow on article to Actor model middle history which reports on the initial implementations, initial applications, and development of the first proof theory and denotational model. Power of the Actor Model Investigations began into the basic power of the Actor model. Carl Hewitt 985argued that because of the use of Arbiters that the Actor model was more powerful than logic programming (see indeterminacy in concurrent computation). A family of Prolog-like concurrent message passing systems using unification of shared variables and data structure streams for messages were developed by Keith Clark, Hervé Gallaire, Stev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Hewitt
Carl Eddie Hewitt () is an American computer scientist who designed the Planner programming language for automated planningCarl Hewitt''PLANNER: A Language for Proving Theorems in Robots''IJCAI. 1969. and the actor model of concurrent computing, concurrent computation, which have been influential in the development of logic programming, logic, functional programming, functional and object-oriented programming. Planner was the first programming language based on procedural plans invoked using pattern-directed invocation from assertions and goals. The actor model influenced the development of the Scheme (programming language), Scheme programming language, the pi calculus, π-calculus, and served as an inspiration for several other programming languages. Education and career Hewitt obtained his PhD in mathematics at MIT in 1971, under the supervision of Seymour Papert, Marvin Minsky, and Mike Paterson. He began his employment at MIT that year, and retired from the faculty of the MIT ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actor Model And Process Calculi
In computer science, the Actor model and process calculi are two closely related approaches to the modelling of concurrent digital computation. See Actor model and process calculi history. There are many similarities between the two approaches, but also several differences (some philosophical, some technical): *There is only one Actor model (although it has numerous formal systems for design, analysis, verification, modeling, ''etc.''); there are numerous process calculi, developed for reasoning about a variety of different kinds of concurrent systems at various levels of detail (including calculi that incorporate time, stochastic transitions, or constructs specific to application areas such as security analysis). *The Actor model was inspired by the laws of physics and depends on them for its fundamental axioms, ''i.e.'' physical laws (see Actor model theory); the process calculi were originally inspired by algebra . *Processes in the process calculi are anonymous, and commun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Garbage Collection (computer Science)
In computer science, garbage collection (GC) is a form of automatic memory management. The ''garbage collector'' attempts to reclaim memory which was allocated by the program, but is no longer referenced; such memory is called '' garbage''. Garbage collection was invented by American computer scientist John McCarthy around 1959 to simplify manual memory management in Lisp. Garbage collection relieves the programmer from doing manual memory management, where the programmer specifies what objects to de-allocate and return to the memory system and when to do so. Other, similar techniques include stack allocation, region inference, and memory ownership, and combinations thereof. Garbage collection may take a significant proportion of a program's total processing time, and affect performance as a result. Resources other than memory, such as network sockets, database handles, windows, file descriptors, and device descriptors, are not typically handled by garbage collection, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry Baker (computer Scientist)
Henry Givens Baker Jr. is an American computer scientist who has made contributions in garbage collection, functional programming languages, and linear logic. He was one of the founders of Symbolics, a company that designed and manufactured a line of Lisp machines. In 2006 he was recognized as a Distinguished Scientist by the Association for Computing Machinery. He is notable for his research in garbage collection, particularly Baker's real-time copying collector, and on the Actor model. Baker received his B.Sc. (1969), S.M. (1973), E.E. (1973), and Ph.D. (1978) degrees at M.I.T. The Chicken Scheme compiler Chicken (stylized as CHICKEN) is a programming language, specifically a compiler and interpreter which implement a dialect of the programming language Scheme, and which compiles Scheme source code to standard C. It is mostly R5RS compliant an ... was inspired by an innovative design of Baker's. Bibliography * * * * * References External links Henry Baker's Archive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific Community Metaphor
In computer science, the scientific community metaphor is a metaphor used to aid understanding scientific communities. The first publications on the scientific community metaphor in 1981 and 1982 involved the development of a programming language named Ether that invoked procedural plans to process goals and assertions concurrently by dynamically creating new rules during program execution. Ether also addressed issues of conflict and contradiction with multiple sources of knowledge and multiple viewpoints. Development The scientific community metaphor builds on the philosophy, history and sociology of science. It was originally developed building on work in the philosophy of science by Karl Popper and Imre Lakatos. In particular, it initially made use of Lakatos' work on proofs and refutations. Subsequently, development has been influenced by the work of Geof Bowker, Michel Callon, Paul Feyerabend, Elihu M. Gerson, Bruno Latour, John Law, Karl Popper, Susan Leigh Star, An ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actor Model (computer Science)
The actor model in computer science is a mathematical model of concurrent computation that treats ''actor'' as the universal primitive of concurrent computation. In response to a message it receives, an actor can: make local decisions, create more actors, send more messages, and determine how to respond to the next message received. Actors may modify their own private state, but can only affect each other indirectly through messaging (removing the need for lock-based synchronization). The actor model originated in 1973. It has been used both as a framework for a theoretical understanding of computation and as the theoretical basis for several practical implementations of concurrent systems. The relationship of the model to other work is discussed in actor model and process calculi. History According to Carl Hewitt, unlike previous models of computation, the actor model was inspired by physics, including general relativity and quantum mechanics. It was also influenced by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
