ispaperestablishesaformalmodelforhybriddiagnosis,novelfeaturesincluding:(1)Itprovidesaunifiedtheoreticalframeworkforutilizingdevicemodelsandheuristicsindiagnosis,whichnaturallyintegratesalltheimportantcomponentsofdiagnosis-thestructuralandbehavioraldescriptionofdevices,faultmodes,thelowerandupperfaultbounds,faultpossibilitiesandheuristicrules-intoadiagnosticsystem.Devicemodelspredictoutputsfrominputs,heuristicrulesinferthepossibilitiesofcertaincomponentsbeingfaultyfromsymptons,andyetthecombinationofbothconstrainseachotherforustoreducethehypothesisspace.(2)Itpresentsatypicalwayofmodelingbehaviorofdevices,towhichthekeyistheintroductionofI-Ofunctionswithindefiniteinputs/outputs.(3)Itcaneasilybeimplementedoveraforware-chaininginferenceengine.
