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Parallel processing and expert systemsWhether it be monitoring the thermal subsystem of Space Station Freedom, or controlling the navigation of the autonomous rover on Mars, NASA missions in the 1990s cannot enjoy an increased level of autonomy without the efficient implementation of expert systems. Merely increasing the computational speed of uniprocessors may not be able to guarantee that real-time demands are met for larger systems. Speedup via parallel processing must be pursued alongside the optimization of sequential implementations. Prototypes of parallel expert systems have been built at universities and industrial laboratories in the U.S. and Japan. The state-of-the-art research in progress related to parallel execution of expert systems is surveyed. The survey discusses multiprocessors for expert systems, parallel languages for symbolic computations, and mapping expert systems to multiprocessors. Results to date indicate that the parallelism achieved for these systems is small. The main reasons are (1) the body of knowledge applicable in any given situation and the amount of computation executed by each rule firing are small, (2) dividing the problem solving process into relatively independent partitions is difficult, and (3) implementation decisions that enable expert systems to be incrementally refined hamper compile-time optimization. In order to obtain greater speedups, data parallelism and application parallelism must be exploited.
Document ID
19910017482
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Lau, Sonie (NASA Ames Research Center Moffett Field, CA., United States)
Yan, Jerry C. (Sterling Federal Systems, Inc., Palo Alto CA., United States)
Date Acquired
September 6, 2013
Publication Date
May 1, 1991
Subject Category
Computer Programming And Software
Report/Patent Number
NASA-TM-103886
NAS 1.15:103886
A-91077
Accession Number
91N26796
Funding Number(s)
PROJECT: RTOP 505-64-54
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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