Reasoning algorithm of multi-value fuzzy causality diagram based on cause-effect possibility allocation

This paper discussed the reasoning algorithm of multi-value fuzzy causality diagram (MFCD) because the previous research on FCD only aimed at single-value, without dealing with multi-value. With the discussing of reasoning problem of MFCD a guideline to solve the problem was introduced, and a normalization method of fuzzy probability of event state was proposed to preprocess data. Based on the idea of conversion of MFCD to single-value fuzzy causality diagram (SFCD), a reasoning algorithm of MFCD based on cause-effect possibility allocation was proposed to deal with the reasoning of MFCD. An example about fault diagnosis of a steam generator in the nuclear power plant demonstrated the effect of the reasoning algorithm of MFCD, and the result was coincident with the fact. The research shows that the reasoning algorithm of MFCD is so effective to solve the problem of MFCD for fault analysis and reasoning, its reasoning process is rigorous.