Controlling Inequality Reasoning in a TMS-Based Analog Diagnosis System

Abstract

A system, called Skordos, has been implemented for model-based diagnosis of analog circuits. One of the difficulties of model-based diagnosis for analog circuits is managing t he tremendous numher of predictions which may he generated by a constraint propagation system. Fortunately, not all of those predictions are valuable for the diagnostic process. A process called hibernation, which is used in Skordos to prevent generation of useless predictions, is introduced and described here, Another technique is introduced and described whcih further assists in controlling the inequality reasoning by exploiting hibernation. This technique involves changing the structure in which values are combined. It uses hibernation as an early filter to reduce the number of interactions resulting from Kirchhoff's current law from exponential to quadratic in the number of interacting variables.