An approach to improving the maintainability of existing rule bases

A rule base (RE) can be both logically sound (complete and correct) and difficult to maintain often because of its complex rule structure. From examinations of several RBs in textbooks, in expert systems shells, and in research projects, complex rule structures have been found to be a rather common phenomenon. This paper reveals the side-effects of carrying complex rule structures in RBs and then provides formal definitions of complex rule structures. Next, it introduces a procedure to detect and simplify such structures. The proposed rule simplification procedure will improve the maintainability of RBs. Its use is illustrated through sample RBs.