Masaki Yumoto, Takenao Ohkawa, Norihisa Komoda, and Fusachika Miyasaka
Qualitative reasoning is a key technology for the model based fault detection, in which a part in failure is identified by comparing the results of reasoning with the real measured values. However, this approach has a problem of increasing possible patterns of behavior of the model enormously because of ambiguity of the qualitative reasoning. To solve the problem, we have proposed the stochastic qualitative reasoning. In this method, all states, whose series compose behavior of the system, have existence probability and the state with relatively small existence probability are eliminated. Through the application of this mechanism to the fault detection of air conditioning systems using field data, we have confirmed the effectiveness of fault detection with the stochastic qualitative reasoning.