KET: A knowledge engineering tool

Abstract

The paper describes a knowledge engineering tool (named KET) designed to facilitate the development of expert systems in various application areas. As an architecture and basic function the system implements the most essential features of domain-independent expert systems: knowledge base interactive development and refinement, forward as well as backward logical inference, utilisation of uncertain knowledge, etc. The KET language integrates a fairly rich subset of the first-order predicate logic with the production systems architecture, covering in this way the advantages of two basic approaches to the knowledge representation problem. The frame-oriented methodology is presented by the following options: the user can define simple concepts by specifying named collections of attribute-value pairs and interconceptual relations; he (or she) can also describe specific objects in a similar way, refering them to already defined concepts in particular. The language achieves additional power by allowing arbitrary terms to be used as values. It is relatively natural in the sense that the knowledge and system behaviour are easily understood in convenient to a naive user terms, i.e. concepts, objects, facts, rules, questions and commands. KET consists of compiler, interpreter, editor, front-end and input-output modules. Its prototype version is written in BASIC and is operational on an IMCO 2 (compatible with Apple II) computer. The paper also aims to compare the system with the logic programming language PROLOG as well as to discuss some issues of implementation and the applicational methodology.