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.Harhalakis, GeorgeSubject: search.filters.subject.data structures

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    Implementation of Rule Based Information Systems for Integrated Manufacturing
    (1992) Harhalakis, George; Lin, Chang-Pin; Mark, Leo; Muro-Medrano, P.R.; ISR
    This paper focuses on the development of a methodology within a software environment for automating the rule based implementation of specifications of integrated manufacturing information systems. The specifications are initially formulated in a natural language and subsequently representted in terms of a graphical representation by the system designer. A new graphical representation tool is based on Updated Petri Nets (UPN) which we have developed as a specialized version of Colored Petri Nets (CPN). The rule based implementation approach utilize the similarity of features between UPN and the general rule specification language used in the implementation. The automation of the translation of UPN to the rule specification language reduces considerably the life cycle for design and implementation of the system. The application presented here deals with the control and management of information flow between Computer Aided Design, Process Planning, Manufacturing Resource Planning and Shop Floor Control databases. This provides an integrated information framework for Computer Integrated Manufacturing (CIM) systems.

    Index Terms - Rule base, information system, computer integrated manufacturing, system modeling, knowledge verification, Petri nets, rule specification language, reasoning, language translation.

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    A PDES Model for Microwave Modules
    (1991) Bahadur, Sudhanshu; Harhalakis, George; Hosier, Robert N.; Minis, Ioannis; ISR
    This paper presents a novel application of the Layered Electrical Product (LEP) model of the PDES (Product Data Exchange specification using STEP) standard. All three levels of the LEP model are developed for a typical microwave module (MWM). The latter comprises of a component layer, the artwork, an insulation layer and a ground plane, which is a complex mechanical part. The nature of the ground plane necessitated the enhancement of the first level of the model to include three dimensional topological entities. Consequently, although the artwork and insulation layers are represented in two-and-a-half dimensions, (which is common practice in the case of Printed Wiring Boards), the ground plane is modeled using the three-dimensional PDES Geometrical and Topological models and the Form Features model. Level II includes the electrical entities of the MWM. New conventions that are necessary to represent particular features of the MWM have been proposed and applied. Based on the intention of PDES, design information that is closely related to manufacturing concerns has been represented in Level III of the model. Both the proposed structure and the contents of this level for MWMs are presented. Material specifications, mechanical features, design specifications for the manufacture of joins, and others are included. Finally, potential applications of the LEP model and especially of Level III in automated process planning and producibility assessment are discussed.