Type of Document	Master's Thesis
Author	Whitehead, John Douglass Hodjat
URN	etd-02062013-040231
Title	Fault diagnosis based on causal reasoning
Degree	Master of Science
Department	Computer Science and Applications
Advisory Committee	Advisor Name Title Roach, John W. Committee Chair Kervick, Daniel M. Committee Member Miller, David P. Committee Member
Keywords	Artificial intelligence
Date of Defense	1988-11-13
Availability	restricted
Abstract A "causal" expert system based on hypothetical reasoning and its application to a Mark 45 turret gun's lower hoist are described. HOIST is a system that performs fault diagnosis without the use of a domain expert or "shallow rules". Rather its "knowledge" is coded directly from a structural specification of the Mark 45 lower hoist. The technology reported here for assisting the lesser acquainted diagnostician differs considerably from the normal rule-based expert system techniques: it reasons about machine failures from a functional model of the device. In a mechanism like the lower hoist, a functional model must reason about forces, fluid pressures and mechanical linkages, that is, qualitative physics. HOIST technology can be directly applied to any exactly specified device for modeling and diagnosis of single or multiple faults. Hypothetical reasoning, the process embodied in HOIST, has general utility in qualitative physics and reason maintenance.
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