EXPERT-SYSTEM SHELLS - SELECTING THE MOST APPROPRIATE DEVELOPMENT ENVIRONMENT

Positive and negative features of commercially available expert system shells are reviewed from the user's perspective. This review does not present the features of any particular shell. Requirements and desira ble features for expert system shells are dependent upon specific appl ication needs and user expertise. Users fall into three general catego ries: (1) students learning about expert systems, (2) domain experts i nvolved in prototyping, testing, and extending a system, or (3) knowle dge engineers with familiarity and skill in knowledge representation m ethodology and building programs. All shells provide four basic functi ons: (1) a knowledge representation scheme, (2) an inference or search mechanism, (3) a means of describing a problem, and (4) status determ ination during problem solving. Despite this commonality, shells lie o n a continuum of relatively simple languages to very elaborate develop ment environments, each having its own purposes and strengths at diffe rent stages of the expert system development cycle. Users should caref ully select the shell most suited to their needs and level of expertis e. User satisfaction will be maximized through consideration of the fo llowing important shell features: (1) knowledge representation schemes , (2) knowledge engineering tools, (3) inference engine and problem so lving strategies, (4) compatability and portability, (5) user interfac e, (6) performance and productivity, and (7) other advanced features p rovided by expert system technology.