PBESS : A Prolog Based Expert System Shell

Building an expert system (ES) requires the developers to have good programming skills, especially when the development starts from scratch. For the beginners who do not have good fundamental in any programming language,
they will find it as a difficult process because programming an ES from scratch is an enormous undertaking. Instead of building an ES from scratch, it is often
possible to borrow extensively from a previously built specific ES. This strategy resulted in tools that are described as shells. This paper presents an ES shell,
namely as PBESS, which was purposely developed to help the beginners to build an expert system. The shell was developed using LPA Prolog. The knowledge representation structure used in this shell has been designed according to rulebased representation method. PBESS uses both forward and backward chaining control strategies to reason with knowledge stored in the knowledge base.