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.computer integrated manufacturing

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Now showing 1 - 7 of 7
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    A Class of Conflict Free Petri Nets Used for Controlling Manufacturing Systems
    (1992) Harhalakis, George; Levantopoulos, Marios M.; Lin, Chang-Pin; Nagi, R.; Proth, J.M.; ISR
    This paper is devoted to the behavior, evaluation and management of non-cyclic discrete systems in general and manufacturing systems in particular. We introduce a special type of Petri nets called CFIOs (Conflict-Free nets with Input and Output transitions). It is shown that CFIOs are live, reversible if consistent, and can be kept bounded under certain conditions. We also develop reduction rules which facilitate the computation of the t-invariants of CFIOs. We then take advantage of the qualitative properties of CFIOs to perform planning in manufacturing systems. Numerical examples illustrate these approaches
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    UPN: A Petri Net Based Graphical Representation of Company Policy Specifications in CIM
    (1992) Harhalakis, George; Lin, Chang-Pin; ISR
    A graphical representation schema - Updated Petri Nets (UPN) - has been developed to model rule based company policy specifications, in the context of computer integrated manufacturing systems. UPN facilitates the modeling of relationships between operations of various related application systems and the database updates and retrievals among various CIM databases. Based on this representation, a hierarchical modeling technique which includes refining and aggregating rules has also been developed. Application of the UPN is demonstrated in designing rule based systems for controlling and integrating the information between manufacturing applications, including Computer Aided Design, Computer Aided Process Planning, Manufacturing Resources Planning, and Shop Floor Control.
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    INformation Systems for Integrated Manufacturing (INSIM)
    (1992) Harhalakis, George; Lin, Chang-Pin; Mark, Leo; ISR
    A mechanism with the potential to control the information flow among all of the manufacturing application systems, in order to streamline factory activities, based on company-specific and company-wide policies and procedures is proposed here. The goal is to achieve a fully integrated manufacturing management system. The INformation Systems for Integrated Manufacturing (INSIM) reflects a design methodology to build a knowledge base to serve as the control mechanism.
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    Hierarchical Modeling Approach for Production Planning
    (1992) Harhalakis, George; Nagi, R.; Proth, J.M.; ISR
    Production management problems are complex owing to large dimensionality, wide variety of decisions of varying scope, focus and time-horizon, and disturbances. A hierarchical approach to these problems is a way to address this complexity, wherein the global problem is decomposed into a series of top-down sub- problems. We advocate that a single planning architecture cannot be employed for all planning problems. We propose a multi-layer hierarchical decomposition which is dependent on the complexity of the problem, and identify the factors influencing complexity. A systematic stepwise design approach for the construction of the hierarchy and inputs required are presented. The subsequent operation of the hierarchy in an unreliable environment is also explained. Aggregation schemes for model reduction have been developed and blended with a time-scale decomposition of activities to provide the theoretical foundation of the architecture. It is also hoped that this methodology can be applied to other such large-scale complex decision making problems.
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    Some Open Problems in the Design and Use of Modern Production Systems
    (1992) Harhalakis, George; Proth, J.M.; ISR
    During the past two decades, manufacturing systems have moved towards automation, integration and modularity. These trends will certainly continue in the future due to the constraints of the market and to evolution of the resources and worker requirements. As a consequence, design and use of manufacturing systems are increasingly expensive. Numerous methods and tools have been developed to face up to this situation, but some complementary aids could be provided for designers and manufacturing engineers. The goal of this paper is to present important open problems whose solutions could certainly improve significantly the design and use of the modern production system.
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    INformation Systems for Integrated Manufacturing (INSIM) - A Design Methodology
    (1991) Harhalakis, George; Lin, Chang-Pin; Mark, Leo; Muro, P.R.; ISR
    Full control and management of information flow in manufacturing has not yet been achieved, mainly because of the data inconsistencies and lack of established functional relationships among different manufacturing application systems. Research toward CIM has been concentrating on the computerization of individual functions, such as computer aided design and shop floor control, and the integration of data relations, such as global database frameworks and distributed database management systems. A mechanism to control the information flow among all of the manufacturing application systems, in order to streamline factory activities based on company-specific and company-wide policies and procedures is proposed here. The goal is to achieve a fully integrated manufacturing management system. The INformation Systems for Integrated Manufacturing (INSIM) reflects a design methodology to build a knowledge base to serve as the control mechanism. This design methodology features an enhanced graphic modeling tool - Updated Petri Nets (UPN) - which is capable of modeling database updates and retrievals, under specific constraints and conditions, and uses a hierarchical modeling approach. Finally, a prototype rule based system, using the INSIM methodology, is being implemented. It assimilates the functionality and assertains the control of information flow between Computer Aided Design, Process Planning, Manufacturing Resource Planning and Shop Floor Control.
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    Formal Representation, Verification and Implementation of Rule Based Information Systems for Integrated Manufacturing
    (1991) Harhalakis, George; Lin, Chang-Pin; Mark, Leo; Muro, P.R.; ISR
    Full control and management of information flow has not yet been achieved, mainly because of the data inconsistencies and lack of established functional relationships among different manufacturing application systems. Research toward CIM has been concentrating on the computerization of individual functions of manufacturing, such as computer aided design and shop floor control, and the integration of data relations, such as global database frameworks and distributed database management systems. A mechanism to control the information flow among all of the manufacturing manufacturing application systems, in order to streamline factory activities based on company-specific and company-wide policies and procedures is proposed here. The goal is to achieve a fully integrated manufacturing management system. The INformation Systems for Integrated Manufacturing (INSIM) reflects a design methodology to build a knowledge base to serve as the control mechanism. The methodology includes knowledge acquisition, graphical modeling, systematic validation and automated implementation. This design methodology features an enhanced graphic modeling tool - Updated Petri Nets (UPN) - which is capable of modeling database updates and retrievals, under specific constraints and conditions and uses a hierarchical modeling approach. Finally, a software package based on the INSIM methodology was developed and a prototype rule based system in Update Dependencies language - a special rule specification language - is being implemented. It assimilates the functionality of information flow between Computer Aided Design, Process Planning, Manufacturing Resource Planning and Shop Floor Control.