Hewlett-packard Company

Douglas R Manley

John M Heumann

George L Booth

An automated analysis system that identifies detectability problems, diagnosability problems, and possible ways to change rank order of diagnoses in a diagnostic system and makes the problems and possible improvements visible to test programmers to aid in test improvement. Components that have no coverage and components that have inadequate coverage (according to a heuristic criteria) are identified as potential detectability problems. Components that are exercised by identical operations in all tests are identified as diagnosability problems. If an incorrect diagnosis is made, the automated analysis system identifies failing tests that have no coverage of any component in the true failure cause. In addition, if an incorrect diagnosis is made, the automated analysis system identifies ways of changing the rank order of diagnoses, including coverages that can be reduced and identification of operation violations that can be eliminated or deliberately added. If no historical data are available, a 'diagnosability index' may be computed by randomly sampling from the set of possible failure syndromes and observing the frequencies with which ties occur among the weights of the top-ranked candidate diagnoses. After historical data becomes available, a diagnosability index may be computed from the frequency with which two candidate diagnoses are assigned identical weights by the model-based diagnostic system over a set of representative failures.

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Loveland, CO, United States of America

Douglas R Manley