Carl Eddie Hewitt ( / h j u ɪ t / ) is an American computer scientist Who designed the Planner programming language for automated schedule [1] and the actor model of concurrent computation , [2] qui-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 Schemeprogramming language, [3] the π-calculus , [4] and served as an inspiration for Several other programming languages. [5]

ucation 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, [6] and retired from the faculty of the MIT Department of Electrical Engineering and Computer Science During the 1999-2000 school year. [7] He est devenu emeritus in the department in 2000. [8] Among the doctoral students supervised That Hewitt During His Time at MIT are Gul Agha , Henry Baker , William Clinger , Irene Greif , and Akinori Yonezawa . [9]

From September 1989 to August 1990, Hewitt was the IBM Chair Visiting Professor in the Department of Computer Science at Keio University in Japan. [10] He has also been a Visiting Professor at Stanford University .


Hewitt is best known for his work on the actor model of computation. For the last decade, his work has been in “inconsistency robustness”, which aims to provide practical rigorous foundations for systems dealing with pervasively inconsistent information. [11] This work Grew out doctoral dissertation de son Focused on the procedural (as Opposed to logical) embedding of Knowledge, qui Was embodied in the Planner programming language .

His publications include aussi contributions in the areas of open information systems , [12] organizational and multi-agent systems , [13] logic programming , [1] concurrent programming , paraconsistent logic [14] and cloud computing . [15]


Main article: Planner (programming language)

The Planner language was developed during the late 1960s as part of Hewitt’s doctoral research in MIT’s Artificial Intelligence Laboratory. Hewitt’s work on Planner introduced the notion of the “procedural embedding of knowledge”, [16] which was an alternative to the logical approach to knowledge encoding for artificial intelligencepioneered by John McCarthy . [17] Planner has been described as “extremely ambitious”. [18] A subset of Planner called Expired Microwave Planner Was Implemented at MIT by Gerry Sussman , Drew McDermott , Eugene Charniak and Terry Winograd [19] and Was used in Winograd ‘ S SHRDLU program, [20] Charniak’s natural language story work, [21] and L. Thorne McCarty’s work on legal reasoning. [22] Planner was almost completely implemented in Popler [23] by Julian Davies at Edinburgh. Planner also influences the later development of other AI research languages ​​such as Muddle and Conniver, [18] as well as the Smalltalk object-oriented programming language. [24] [22] Planner was almost completely implemented in Popler [23] by Julian Davies at Edinburgh. Planner also influences the later development of other AI research languages ​​such as Muddle and Conniver, [18] as well as the Smalltalk object-oriented programming language. [24] [22] Planner was almost completely implemented in Popler [23] by Julian Davies at Edinburgh. Planner also influences the later development of other AI research languages ​​such as Muddle and Conniver, [18] as well as the Smalltalk object-oriented programming language. [24]

Hewitt’s own work on Planner continued with Muddle (later called MDL), which was developed in the early 1970s by Sussman, Hewitt, Chris Reeve, and David Cressey as a stepping-stone towards a full implementation of Planner. Muddle was implemented as an extended version of Lisp and Lisp, Lisp, and Common Lisp. [18] However, in late 1972 hewitt abruptly halted his development of the planner design in his thesis, when he and his graduate students invented the actor model of computation.

Actor model

Main article: Actor model

Hewitt’s work on the actor model of computation HAS spanned over 30 years, Beginning with the introduction of the model in a 1973 paper authored by Hewitt, Peter Bishop, and Richard Steiger, [25] and Including new results is actor model semantics published as recently As 2006. [26] Much of this work was carried out in collaboration with students in Hewitt’s Message Passing Semantics Group at MIT’s Artificial Intelligence Lab. [27]

Sussman and Steele developed the Scheme programming language in an effort to gain a better understanding of the actor model. [28] [29] A number of theoretical and temporal constraints on the use of a lambda in a lambda calculus. programming languages Were Developed SPECIFICALLY to Implement the actor model, Such as ACT-1, [30] SALSA , [31] Caltrop, [32] E [5] and ActorScript. [33] The actor model also influences the development of the π-calculus . [34] (See actor model and process calculation history .)

Selected works

  • Carl Hewitt (1969). PLANNER: A Language for Proving Theorems in Robots IJCAI’69.
  • Carl Hewitt, Peter Bishop and Richard Steiger (1973). A Universal Modular Actor Formalism for Artificial Intelligence IJCAI’73.
  • Carl Hewitt and Henry Baker (1977a). Laws for Communicating Parallel Processes IFIP’77.
  • Carl Hewitt and Henry Baker (1977b). Actors and Continuous Functionals Proceedings of IFIP Working Conference on Formal Description of Programming Concepts. August 1-5, 1977.
  • William Kornfeld and Carl Hewitt (1981). The Scientific Community Metaphor IEEE Transactions on Systems, Man, and Cybernetics. January 1981.
  • Henry Lieberman and Carl E. Hewitt (1983). A Real-Time Garbage Collector Based on the Lifetimes of Objects Communications of the ACM, 26 (6).
  • Carl Hewitt (1985). The Challenge of Open Systems Byte Magazine. April 1985. (Reprinted in The foundation of artificial intelligence-a sourcebook Cambridge University Press. 1990

See also

  • Scientific community metaphor


  1. ^ Jump up to:b Carl Hewitt. PLANNER: A Language for Proving Theorems in Robots IJCAI. 1969.
  2. Jump up^ Filman, Robert; Daniel Friedman (1984). “Actors”. Coordinated Computing – Tools and Techniques for Distributed Software . McGraw-Hill. p. 145. ISBN  0-07-022439-0 . Carl Hewitt and his colleagues at MIT are developing the Actor model.
  3. Jump up^ Krishnamurthi, Shriram (December 1994). “An Introduction to Scheme” . Crossroads . 1 (2): 19. doi : 10.1145 / 197149.197166 .
  4. Jump up^ Milner, Robin (January 1993). “ACM Turing Award Lecture: The Elements of Interaction” (PDF) . Communications of the ACM . 36 (1): 78. doi : 10.1145 / 151233.151240 .
  5. ^ Jump up to:b Mark S. Miller (2006). “Robust Composition – Towards a Unified Approach to Access Control and Concurrency Control”(PDF) . PhD dissertation. Johns Hopkins University . Retrieved 2007-05-26 .
  6. Jump up^ MIT News Office (April 10, 1996). “Quarter Century Club inducts 73 new members” . Retrieved 2007-06-19 .
  7. Jump up^ John V. Guttag (2000). “MIT Reports to the President 1999-2000 – Department of Electrical Engineering and Computer Science” . Retrieved 2007-06-19 .
  8. Jump up^ “Stanford EE Computer Systems Colloquium” . Stanford University . Retrieved 30 July 2011 .
  9. Jump up^ Carl Hewitt (2007). “Academic Biography of Carl Hewitt” . Retrieved 2007-11-22 .
  10. Jump up^ Ryuichiro Ohyama (1991). “Department of Computer Science Recent and Current Visiting Professors” . Retrieved 2007-06-19.
  11. Jump up^ Hewitt, Carl; Woods, John, eds. (2015). Inconsistency Robustness . Studies in Logic. 52 . College Publications. p. 614.ISBN  9781848901599 .
  12. Jump up^ Carl Hewitt (1986). “Offices Are Open Systems”. ACM Trans. Inf. System . 4 (3): 271-287. Doi : 10.1145 / 214427.214432 .
  13. Jump up^ Jacques Ferber (1999). Multi-Agent Systems: An Introduction to Distributed Artificial Intelligence . Addison-Wesley.
  14. Jump up^ Hewitt, Carl (2008). “Large-scale Organizational Computing requires Unstratified Reflection and Strong Paraconsistency” . In Sichman, Jaime; Noriega, Pablo; Padget, Julian; Ossowski, Sascha. Coordination, Organizations, Institutions, and Standards in Agent Systems III . Springer-Verlag. ISBN  978-3-540-79002-0 .
  15. Jump up^ Carl Hewitt (September-October 2008). “ORGs for Scalable, Robust, Privacy-Friendly Cloud Computing Client”. IEEE Internet Computing . 12 (5).
  16. Jump up^ Carl Hewitt. Procedural Embedding of Knowledge in PlannerIJCAI. 1971.
  17. Jump up^ Philippe Rouchy,Aspects of Prolog History: Logic Programming and Professional Dynamics, TeamEthno-Online Issue 2, June 2006, 85-100.
  18. ^ Jump up to:c Sussman, Gerald Jay; Guy L. Steele (1998). “The First Report on Scheme Revisited” (PDF) . Higher-Order and Symbolic Computation . Boston: Kluwer Academic Publishers. 11(4): 399-404. Doi : 10.1023 / A: 1010079421970 . Retrieved 2009-01-03 .
  19. Jump up^ Gerry Sussman and Terry Winograd. Micro-planner Reference Manual AI Memo No, 203, MIT Project MAC, July 1970.
  20. Jump up^ Terry Winograd. Procedures have a Representation for Data in a Computer Program for Understanding Natural Language MIT AI TR-235. January 1971.
  21. Jump up^ Marvin Minsky and Seymour Papert. “Progress Report on Artificial Intelligence” MIT AI Memo 252. 1971.
  22. Jump up^ L. Thorne McCarty. “Reflections on TAXMAN: An Experiment on Artificial Intelligence and Legal Reasoning” Harvard Law Review. Flight. 90, No. 5, March 1977
  23. Jump up^ Julian Davies. Popler 1.6 Reference Manual University of Edinburgh, TPU Report No. 1, May 1973.
  24. Jump up^ Kay, Alan; Stefan Ram (2003-07-23). “E-Mail of 2003-07-23” . Dr. Alan Kay on the Meaning of “Object-Oriented Programming” . Retrieved 2009-01-03 .
  25. Jump up^ Carl Hewitt; Peter Bishop & Richard Steiger (1973). “A Universal Modular Actor Formalism for Artificial Intelligence”. IJCAI.
  26. Jump up^ Carl Hewitt What is Commitment? Physical, Organizational, and Social COIN @ AAMAS. April 27, 2006.
  27. Jump up^ Mark S. Miller. “Actors: Foundations for Open Systems” . Retrieved 2007-06-20 .
  28. Jump up^ Hewitt, Carl (2010). “Actor Model of computation”. arXiv :1008.1459  [ cs.PL ].
  29. Jump up^ Sussman, Gerald Jay; Guy L. Steele (1998). “The First Report on Scheme Revisited” (PDF) . Higher-Order and Symbolic Computation . Boston: Kluwer Academic Publishers. 11 (4): 399-404. Doi : 10.1023 / A: 1010079421970 .
  30. Jump up^ Henry Lieberman, “Concurrent Object-Oriented Programming in Act 1,” In Object-Oriented Concurrent Programming, Yonezawa A. and M. Tokoro, eds., MIT Press, 1987.
  31. Jump up^ C. Varela and G. Agha. Programming Dynamically Reconfigurable Open Systems with SALSA. OOPSLA 2001 Intriguing Technology Track. ACM SIGPLAN Notices, 36 (12): 20-34, December 2001.
  32. Jump up^ Johan Eker; Jörn W. Janneck. “An introduction to the Caltrop actor language” (PDF) . Retrieved 2007-06-20 .
  33. Jump up^ Hewitt, Carl (2010). “ActorScript TM extension of C # TM> , Java TM, andObjective C Tm “. arXiv : 1008.2748  [ cs.PL ].
  34. Jump up^ Robin Milner Elements of interaction: Turing Award reading CMAC. January 1993.

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