No Faults in Structure? How to Diagnose Hidden Interactions

Abstract

A model based diagnosis procedure traces connections between components only where these are provided explicitly in the system description. Consequently structure faults fall between the meshes. This problem has been known since research started in this field ([Davis 84]). but no general solution has been presented so far. We present a procedure to diagnose structure faults. based on a scheme to detect hidden interactions guided by the observation that structure faults lead to discrepancies in apparently unrelated areas and which in contrast to [Preist, Welham 90] modifies the system description dynamically. Like Davis' approach the one presented in the paper is based on the principle that an interaction can occur only where components are adjacent in some way ([Davis 84]). Unlike Davis' approach we introduce an explicit representation scheme for hidden interactions. A hidden interaction mode/links a required contextual. behaviour independent constellation to the impact of the interaction on the overall system behaviour. In order to control hidden interaction hypotheses we exploit the structure of diagnoses based on behavioural mode assignments.