Developing and running expert systems with PESYS

Recently there has been a growing interest in developing expert system shells that provide a user-friendly interface for the development of expert systems. In this paper we describe PESYS (Pascal Expert SYstem Shell) which is a software tool that enables the user to express his/her knowledge in natural language. In order for PESYS to ‘understand’ the natural language formalisms ‘commonsense’ knowledge is required and a method has been developed which obtains the basic meaning from sentences. We present this method and also how it is accomplished by PESYS