Study of an explanation mechanism in expert system based on fault tree for safety risk assessment

Explanation mechanism provides an understanding window about the reasoning process of expert system for customers. It is an important component of expert system and the explanation function is one of the important features of expert system. In the expert system of safety risk assessment, we used synthesis database to record the solving process and result. Among the synthesis database, the overall data district record overall information and the partial data district record partial information. The solving process is recorded by a reasoning queue based on reasoning-fault tree and explanation information is record in a form structure of relation database. We adopted the method of pre-text combined with path-following to realize the explanation mechanism.