“…From the linear GPA method developed by Urban in the late 1960's [13], a series of GPA methods were proposed, such as an adaptive nonlinear GPA method [7], artificial neural networks [3], rule-based expert system and rule-based fuzzy expert system [11], and genetic algorithm [4,12,17]. The merit of artificial intelligence methods, such as neural network, rough set [14], Bayesian network [9,10] and rule based expert system, is that they do not need a gas turbine performance model, as only the relation information between fault symptom and degradation is needed. They can easily isolate the faulty component.…”