Planner is a programming language designed by Carl Hewitt at MIT, and first published in 1969. First, subsets such as Micro-Planner and Pico-Planner were implemented, and then essentially the whole language was implemented as Popler by Julian Davies at the University of Edinburgh in the POP-2 programming language. Derivations such as QA4, Conniver, QLISP and Ether were important tools in artificial intelligence research in the 1970s, which influenced commercial developments such as Knowledge Engineering Environment (KEE) and Automated Reasoning Tool (ART).
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 final 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.
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.
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.
In theoretical computer science, Actor model theory concerns theoretical issues for the Actor model.
In computer science, Actor model implementation concerns implementation issues for the Actor model.
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.
Henry Givens Baker Jr. is an American computer scientist who has made contributions in garbage collection, functional programming languages, and linear logic. He was also 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.
In computer science, the Actor model, first published in 1973, is a mathematical model of concurrent computation.
In computer science, unbounded nondeterminism or unbounded indeterminacy is a property of concurrency by which the amount of delay in servicing a request can become unbounded as a result of arbitration of contention for shared resources while still guaranteeing that the request will eventually be serviced. Unbounded nondeterminism became an important issue in the development of the denotational semantics of concurrency, and later became part of research into the theoretical concept of hypercomputation.
In denotational semantics and domain theory, power domains are domains of nondeterministic and concurrent computations.
Indeterminacy in concurrent computation is concerned with the effects of indeterminacy in concurrent computation. Computation is an area in which indeterminacy is becoming increasingly important because of the massive increase in concurrency due to networking and the advent of many-core computer architectures. These computer systems make use of arbiters which give rise to indeterminacy.
The actor model and process calculi share an interesting history and co-evolution.
The denotational semantics of the Actor model is the subject of denotational domain theory for Actors. The historical development of this subject is recounted in [Hewitt 2008b].
Programming language theory (PLT) is a branch of computer science that deals with the design, implementation, analysis, characterization, and classification of formal languages known as programming languages and of their individual features. It falls within the discipline of computer science, both depending on and affecting mathematics, software engineering, linguistics and even cognitive science. It has become a well-recognized branch of computer science, and an active research area, with results published in numerous journals dedicated to PLT, as well as in general computer science and engineering publications.
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.
Akinori Yonezawa is a Japanese computer scientist specializing in object-oriented programming, distributed computing and information security. Being a graduate of the University of Tokyo, Yonezawa has a Ph.D in computer science from MIT in the Actor group at the MIT AI Lab. He currently teaches at the University of Tokyo. He is the designer of ABCL/R, a reflective subset of the first concurrent object-oriented programming language ABCL/1.
William D. Clinger is an associate professor in the Khoury College of Computer Sciences at Northeastern University. He is known for his work on higher-order and functional programming languages, and for extensive contributions in helping create and implement international technical standards for the programming language Scheme via the Institute of Electrical and Electronics Engineers (IEEE) and American National Standards Institute (ANSI). Clinger was an editor of the second through fifth Revised Reports on Scheme (R2RS – R5RS), and an invited speaker on Scheme at the Lisp50 conference celebrating the 50th birthday of the language Lisp. He has been on the faculty at Northeastern University since 1994.
Carl Eddie Hewitt is an American computer scientist who designed the Planner programming language for automated planning and the actor model of concurrent computation, which have been influential in the development of logic, 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, the π-calculus, and served as an inspiration for several other programming languages.
Henry Lieberman is an American computer scientist at the MIT CSAIL in the fields of programming languages, artificial intelligence and human-computer interaction. He received the 2018 ACM Impact Award Intelligent User Interaction for work on mining affect from text and has been applied to the problem of prevention of cyberbullying. He has been a principal research scientist at the Media Lab and Director of the Software Agents Research group.
