NIST Special Publication 500-188 Computer Systems Guide Expert System to Technology Building Tools for CU.OS.MMDEEPRACRETMENTOF Microcomputers National Instituteof Standardsand Technology Christopher E. Dabrowski Nisr EHzabeth N. Fong NATLINST OFSTANDSTECHR.I.C- REFERENCE N!ST I PUBLICATIONS f -QC 100 .U57 //500-188 1991 mi NIST Special Publication 500-188 /p/'/( 7^ Guide Expert System to Building Tools for Microcomputers Christopher E. Dabrowski EHzabeth N. Fong Computer Systems Laboratory National Institute of Standards and Technology Gaithersburg, MD 20899 July 1991 U.S. DEPARTMENT OF COMMERCE Robert A. Mosbacher, Secretary NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY John W. Lyons, Director Reports on Computer Systems Technology The National Institute of Standards and Technology (NIST) has a unique responsibility for computer systenns technology within the Federal government. NIST's Computer Systems Laboratory (CSL) devel- ops standards and guidelines, provides technical assistance, and conducts research for computers and related telecommunications systems to achieve more effective utilization of Federal information technol- ogy resources. CSL's responsibilities include development of technical, management, physical, and ad- ministrative standards and guidelines for the cost-effective security and privacy of sensitive unclassified information processed in Federal computers. CSL assists agencies in developing security plans and in improving computer security awareness training. This Special Publication 500 series reports CSL re- search and guidelines to Federal agencies as well as to organizations in industry, government, and academia. National Institute of Standards and Technology Special Publication 500-188 Natl. Inst. Stand. Technol. Spec. Publ. 500-188, 147 pages (July 1991) CODEN: NSPUE2 U.S. GOVERNMENT PRINTING OFFICE WASHINGTON: 1991 PREFACE The Computer Systems Laboratory (CSL) (formerly the Institute for Computer Sciences and Technology (ICST)) within the National Institute of Standards and Technology (NIST) has a mission under Public Law 89-306 (Brooks Act) to promote the "economic and efficient purchase, lease, maintenance, operation, and utilization of automatic data processing equipment by Federal departments and agencies." When a potentially valuable technology first appears, CSL may be involved in research and evaluation. Later on, standardization of the results of this research, in cooperation with voluntary industry standards bodies, may best serve Federal interests. Finally, CSL helps Federal agencies make practical use of existing standards and technology through consulting services and the development of supporting guidelines and software. This report provides system managers, planners, and potential expert system developers with a readable description of expert system building tools for the microcomputer environment. Certain commercial software products and companies are identified in this report. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the products identified are necessarily the best available for the purpose. iii ACKNOWLEDGMENTS The technical work for this report was done through extensive review of published literature and hands-on analysis of commercial expert system building tools. We would like to thank the vendors for their cooperation and for their donation of these tools to the CSL Knowledge-Based Systems Laboratory. We would also like to acknowledge the contributions of David Jefferson, Steven Ray, Daniel Benigni, Joseph Collica, and Bruce Rosen, of NIST who reviewed earlier versions of this paper and provided valuable advice. Candy Leatherman and Jennifer Lindeman proofread the document and helped with preparing figures and tables. Special thanks is also due to Steven Oxman, whose advice in preparing the final version of this report was particularly valuable. We also wish to express appreciation to Kenneth Reddy who provided programming assistance during the analysis and evaluation of tools. v ABSTRACT Microcomputer-based expert system building tools (microcomputer-based ESBTs) sometimes known as expert system , shells, are software packages for development of expert systems that run on microcomputers. This report provides system managers, planners, and potential expert system developers with a readable description of ESBTs for microcomputers including a detailed description of specific tool features and the capabilities they support. The technical content of this report is based on analysis of commercially available ESBTs. However, individual commercial products are not described, compared, or ranked. Keywords: artificial intelligence; expert system; expert system building tool; expert system shell; inference; knowledge base; knowledge-based system; knowledge engineering; knowledge representation; microcomputer; object-oriented programming; production rule. vii