On Rule Induction Method Based Rough Sets in Diagnostic Expert System

It usually takes a long period to acquire plant disease knowledge using the traditional methods during the development of expert system. This paper describes relations between rough set theory and rulebased description of plant diseases, which corresponds to the process of knowledge acquisition of expert system. Then the exclusive rules, inclusive rules and disease images of rapeseed disease are built based on the PDES diagnosis model, and the definition of probability rule is put forward. At last, the paper presents the rule-based automated induction reasoning method, including exhaustive search, post-processing procedure, estimation for statistic test and the bootstrap and resampling methods. We also introduce automated induction of the rule-based description, which is used in our plant diseases diagnostic expert system. The experimental results show that rough set theory gives a very suitable framework to represent processes of uncertain knowledge extraction.