Institute for Systems Research Technical Reports

Permanent URI for this collectionhttp://hdl.handle.net/1903/4376

This archive contains a collection of reports generated by the faculty and students of the Institute for Systems Research (ISR), a permanent, interdisciplinary research unit in the A. James Clark School of Engineering at the University of Maryland. ISR-based projects are conducted through partnerships with industry and government, bringing together faculty and students from multiple academic departments and colleges across the university.

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Author: search.filters.author.Evett, Matthew

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    Knowledge Representation in PARKA - Part 2: Experiments, Analysis, and Enhancements
    (1992) Spector, Lee; Andersen, William; Hendler, James A.; Kettler, Brian; Schwartzman, Eugene; Woods, Cynthia; Evett, Matthew; ISR
    Our research group has designed and implemented a symbolic knowledge representation system called PARKA which runs on the Connection Machine, a massively parallel SIMD computer [9]. The semantics of this system are discussed in [11]. The details of the Connection Machine implementation and discussions of performance considerations can be found in [3], [4], [5], [6] and [7]. In the past year the PARKA project has made significant advances along several fronts of both theoretical and practical significance. This paper summarizes some of this work and outlines directions for further research.
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    PRA: Massively Parallel Heuristic Search
    (1991) Evett, Matthew; Hendler, James A.; Mahanti, Ambuj; Nau, D.; ISR
    In this paper we describe a variant of A* search designed to run on the massively parallel, SIMD Connection Machine. The algorithm is designed to run in a limited memory by use of a retraction technique which allows nodes with poor heuristic values to be removed from the open list, until such time as they may need reexpansion, more promising paths having failed. Our algorithm, called PRA* (for Parallel Retraction A*), is designed to maximize use of the Connection Machine's memory and processors. In addition, the algorithm is guaranteed to return an optimal path when an admissable heuristic is used. Results comparing PRA* to Korf's IDA* for the fifteen-puzzle show significantly fewer node expansions for PRA*. In addition, empirical results show significant parallel speedups, indicative of the algorithm's design for high processor utilization.
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    BackProp: A Tool for Learning About Connectionist Architectures.
    (1988) Pollack, Jordan; Evett, Matthew; Hendler, James A.; ISR
    This paper provides an implementation, in Common Lisp, of an "epoch learning algorithm," a simple modification of the standard back-propagation algorithm. This implementation is not intended to be a general purpose, high powered back-propagation learning system. Rather, this paper seeks only to provide a simple implementation of a popular and easily understood connectionist learning algorithm. It is intended to be a, teaching tool for AI researchers wishing to familiarize themselves or their students with back-propagation in a language with which they are comfortable.