Title page for ETD etd-02062013-040231
|Type of Document
||Whitehead, John Douglass Hodjat
||Fault diagnosis based on causal reasoning
||Master of Science
||Computer Science and Applications
|Roach, John W.
|Kervick, Daniel M.
|Miller, David P.
|Date of Defense
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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