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REDEX - The ranging equipment diagnostic expert systemREDEX, an advanced prototype expert system that diagnoses hardware failures in the Ranging Equipment (RE) at NASA's Ground Network tracking stations is described. REDEX will help the RE technician identify faulty circuit cards or modules that must be replaced, and thereby reduce troubleshooting time. It features a highly graphical user interface that uses color block diagrams and layout diagrams to illustrate the location of a fault. A semantic network knowledge representation technique was used to model the design structure of the RE. A catalog of generic troubleshooting rules was compiled to represent heuristics that are applied in diagnosing electronic equipment. Specific troubleshooting rules were identified to represent additional diagnostic knowledge that is unique to the RE. Over 50 generic and 250 specific troubleshooting rules have been derived. REDEX is implemented in Prolog on an IBM PC AT-compatible workstation. Block diagram graphics displays are color-coded to identify signals that have been monitored or inferred to have nominal values, signals that are out of tolerance, and circuit cards and functions that are diagnosed as faulty. A hypertext-like scheme is used to allow the user to easily navigate through the space of diagrams and tables. Over 50 graphic and tabular displays have been implemented. REDEX is currently being evaluated in a stand-alone mode using simulated RE fault scenarios. It will soon be interfaced to the RE and tested in an online environment. When completed and fielded, REDEX will be a concrete example of the application of expert systems technology to the problem of improving performance and reducing the lifecycle costs of operating NASA's communications networks in the 1990s.
Document ID
19900030984
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Luczak, Edward C.
(Computer Sciences Corp. Beltsville, MD, United States)
Gopalakrishnan, K.
(Computer Sciences Corp. Beltsville, MD, United States)
Zillig, David J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1989
Publication Information
Publication: Telematics and Informatics
Volume: 6
Issue: 4-Mar
ISSN: 0736-5853
Subject Category
Space Communications, Spacecraft Communications, Command And Tracking
Accession Number
90A18039
Funding Number(s)
CONTRACT_GRANT: NAS5-31500
Distribution Limits
Public
Copyright
Other

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