Model-based diagnosis using qualitative causal model and set-covering

A model-based diagnostic system is proposed for continuous physical devices such as a thermal power plant. The aim of model-based diagnosis is to find faulty components in the model from observations. Set-covering is an approach to diagnosis when the causal relations between symptoms and disorders are clearly defined. The new method combines the model-based approach and set-covering approach. The authors introduce the qualitative causal model (QCM) and define symptoms and qualitative disorders in QCM. The system has two submodules to calculate diagnosis from symptoms. The qualitative propagation module calculates the causal relations between the symptoms and the qualitative disorders. The BIPARTITE module based on set-covering generates all the diagnoses using these relations. The proposed method is proved to realize the diagnosis from first principles in the continuous physical domain