Where Intelligent Technology Meets the Real World
Contact PC AI
OPS Programming Language

Overview: Carnegie-Mellon University scientists Herbert Simon and Allen Newell have investigated human problem-solving processes for many decades. One of their ideas, the production system, represents knowledge as a set of condition-action rules (also called "if-then rules"). If the conditions for a rule are satisfied, the rule's specified action occurs. In the late 70s, Charles Forgy developed OPS5, a programming language which embodies this idea. The production system became the dominant knowledge representation methodology in expert systems, and OPS5 became popular among expert system developers. OPS5 stores data in working memory, and if-then rules in production memory. Rules in OPS5 are completely independent of one another. They can be placed in production memory in any order. If the data in working memory match the conditions of a rule in production memory, the rule's actions take place. Possible actions include modifying the contents of working memory (which might then match the conditions of another rule), reading information from a file, displaying information on the screen, and calling external programs. In some versions of the language, a rule's actions can cause a new rule to be created, allowing the development of systems that learn.

OPS5's built-in inference mechanism, forward chaining, starts from a set of data in working memory and causes a sequence of rules to be applied until a goal is satisfied. The other prominent expert system inferencing procedure is backward chaining, in which a goal to be achieved causes subgoals to be satisfied until a problem solution is found. Backward chaining can be implemented in OPS5 with some work. (Reference: LANGUAGES OF AI by Joseph Schmuller, September/October 1991, page 21)


Glossary Link - OPS Programming Language


To Logo Programming Language
To Prolog Programming Language

OPS Information on the Internet
Tool - PD OPS5 Public domain implementation of an OPS5 interpreter. Uploadable using FTP. 

Sponsors of PC AI - OPS Vendors
Production Systems Technology Phone: (412)683-4000, Fax: (412)683-6347, Email: info@pst.com

Dynamic Search Engine References
Search the web for "ops language" references using:
Google Lycos Yahoo InfoSeek Alta Vista

Article References
Three Case Histories: Ops83 At Work Czajkowski, A. (1990) PC AI, 4(1), 30. 
OPS Languages Forgy, C. (1995) PC AI, 9(5), 16. 

Book References
Programming Expert Systems in OPS 5 Brownston, L., Farrell, R., Kant, E., Martin, N. (1985) Reading MA: Addison-Wesley, pps 471 
Search: Enter keywords... 

Amazon.com                       logo
Rule-Based Programming in OPS 5 Cooper, T. and Wogrin, N. (1988) San Mateo, CA: Morgan-Kaufmann 

Other AI Info Categories

AI Languages ------------------------------------------------------> C++
Blackboard Technology Client/Server Dylan
Creative Thinking Data Warehouse/Mining Forth
Distributed Computing Expert Systems Lisp
Fuzzy Logic General AI Sites Logo
Genetic Algorithms Help Desk Prolog
Intelligent Agents Intelligent Applications Scheme
Internet Logic Programming Smalltalk
Machine Learning Modeling and Simulation  
Multimedia Natural Language Processing  
Neural Networks Object Oriented Development  
Optical Character Recognition Robotics  
Speech Recognition Virtual Reality  

PC AI Magazine

PCAI.TH @ gmail.com
Copyright (C) 2001-2002, All rights reserved
Designed by Terry H. and the web team at Knowledge Technology: Comments? webmaster @ pcai.com