LES: (Lockheed Expert System): A Model-Based Expert System for Electronic Maintenance,
LOCKHEED MISSILES AND SPACE CO INC PALO ALTO CA PALO ALTO RESEARCH LAB
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Existing Automatic Test Equipment is often inadequate for quickly isolating component failure in large electronic systems. The Lockheed Expert System LES has been designed to guide less-experienced maintenance personnel in the fault diagnosis of electronic systems. LES uses not only the knowledge of the expert diagnostician captured in the familiar form of IF-THEN rules, but also knowledge about the structure, function, and causal relations of the device under study to perform rapid isolation of the module causing the failure. In addition to aiding the engineer in troubleshooting an electronic device, LES can also explain its reasoning and actions to the user, and can provide extensive database retrieval and graphics capabilities. This discusses the application of LES to a large signal-switching network containing Built-In Test Equipment BITE. By adding rules, database information, and a few special procedures to the general LES framework, we were able to have a working system in a much shorter time four man-months than would have been possible starting afresh.