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SPECIAL FEATURE Expert Computer Systems Disclosure Number: IPCOM000131593D
Original Publication Date: 1983-Feb-01
Included in the Prior Art Database: 2005-Nov-11
Document File: 30 page(s) / 86K

Publishing Venue

Software Patent Institute

Related People

Dana S. Nan: AUTHOR [+2]


This article discusses the techniques used in expert systems on each of these levels. Since these systems use a combination of Al problem-solviAg and knowledgerepresentation techniques, information on these areas is also included.

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SPECIAL FEATURE Expert Computer Systems

Dana S. Nan,

University of Maryland

Artificial intelligence is no longer science theory. A variety of "thinking" systems are out of the laboratory and successfully solving problems using AI knowledge-representation techniques.

Only recently has artificial intelligence advanced to the point that AI projects are accomplishing practical results. Most of these results can be attributed to the design and use of expert systems, problem-solving computer programs that can reach a level of performance comparable to that of a human expert in some specialized problem domain.

What distinguishes such a system from an ordinary applications program is not readily apparent in this definition. Certainly, applications programs make use of specialized problem-solving knowledge, and many of them reach high levels of performance. Probably the main difference is that in most expert systems, the model of problem-solving in the application domain is explicitly in view as a separate entity or knowledge base rather than appearing only implicitly as part of the coding of the program. This knowledge base is manipulated by a separate, clearly identifiable control strategy. Such a system architecture provides a convenient way to construct sophisticated problem-solving tools for many different domains.

Expert systems have been developed for a number of different problem domains, and Table I lists only a few of these systems. In addition, several computer systems and languages are being developed to provide tools for creating expert systems, including AGES, ARS,2 Emycin,3 Expert,4 KMS,5 and oPS.6 Such systems typically provide formats or languages for representing both procedural knowledge and declarative knowledge, control structures for manipulating this knowledge, and user interfaces.

Ordinary computer programs organize knowledge on two levels: data and program. Most expert computer systems, however, organize knowledge on three levels: data, knowledge base, and control. Computers organized in this way are often called knowledge-based systems.

On the data level is declarative knowledge about the particular problem being solved and the current state of

affairs in the attempt to solve the problem. On the knowledge-base level is knowledge specific to the particular kind of problem that the system is set up to solve. This knowledge is used by the system in reasoning about the problem and is often given in the form of operators, or "pattern-invoked programs. " One, many, or no operators may be applicable to...