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.Mark, Leo

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Now showing 1 - 10 of 22
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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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    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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    Update Dependencies in the Relational Model
    (1991) Mark, Leo; Roussopoulos, N.; Cochrane, Roberta J.; ISR
    Relational database systems suffer from the lack of a rich update language. In this paper we present the Update Dependency Language which allows the database designer to specify a procedure for each update that is activated when attempts are made to perform the update. Each procedure integrates the update dependencies for an update and provides an operational semantics for the update which is maintained by the system. We provide a formal definition for this language, illustrate its use, and discuss concurrency control issues related to integrating such a language into a database system.
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    Relational Database Support for Complex Objects Defined by Grammars
    (1991) Cochrane, Roberta J.; Mark, Leo; ISR
    Context-free grammars provide the basis for many useful tools such as parsergenerators, compiler-compilers and syntax-directed editors. This paper demonstrates the potential benefits obtained when context-free grammars are used to define complex objects in the relational model. The grammar formalism facilitates relational queries on the hierarchical structure of these objects and promotes the use of grammar-based tools as front ends to relational database systems.
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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.
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    Automating Relational Database Support for Objects Defined by Context-Free Grammars - the Intension-Extension Framework.
    (1989) Mark, Leo; Cochrane, Roberta J.; ISR
    We are designing a framework that provides a common foundation for the integration of databases with other areas of computer science and engineering. This framework is based on the fundamental concepts: context-free grammars and database relations.Our goal is to provide automatic database support for complex objects that can be described by context-free grammars. Such support should include Data Definition, Data Update, Grammar Catalog Generation, Data Retrieval, and Database Restructuring. This paper addresses the first three areas: Data Definition: GeneRel automatically generates a set of normalized relational schemes under which ob,iects derived from a given grammar can be stored. Data Update: GenParse automatically generates parser specifications with insertion statements for storing sentences acceptable by a given grammar. Grammar Catalog Generation: GenRel, when applied to a meta-grammar, generates relations in which grammars derived from the meta-grammar can be stored. Furthermore, GenRel and GenParse can be implemented through the specification of semantic actions in a compiler-compiler specification of the meta-grammar. We believe that GenRel and GeneParse, together with our related efforts towards providing support for data retrieval and database restructuring in this environment, provide a tool that eliminates the need for manual relational database design, enhances data storage and querying, aids in the process of database restructuring, and provides a common foundation for the integration of databases with other areas of computer science and engineenng.
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    Grammars and Relations.
    (1989) Mark, Leo; Cochrane, Roberta J.; ISR
    Programming languages and databases have evolved on separate foundations and with separate goals for many years. Buzzwords such as persistent data objects, objectoriented databases and software engineering databases reflect increased activity aimed at integrating the two areas at their current state of evolution. This paper suggests that we retum to basics and consider the foundation of the two areas, grammars and relations, as a basis for their integration. We present an algorithm, GeneRel, which given a grammar automatically generates a set of normalized relations in which objects derived from the grammar can be stored. We demonstrate how the algorithm applied to a meta- grammar generates relations in which grammars derived from the meta-grammar can be stored. We show how an extended relational algebra can be used to retrieve information about stored grammars and stored objects derived from the grammars. We outline an algorithm, GeneView, which given a set of non-terminals from a grammar generates a set of view definitions on the created relations.
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    Interoperability of Multiple Autonomous Databases .
    (1989) Litwin, Witold; Mark, Leo; Roussopoulos, N.; ISR
    Database systems were a solution to the problem of shared access to heterogeneous files created by multiple autonomous applications. To make the data usage easier, one proposed to replace the autonomous files by a globally integrated collection of data called a database. The idea was successful to a large extent and there are now many databases distributed over local and longhaul networks and frequently even on the same larger computer. Unavoidably, users now need shared access to multiple autonomous databases. The question arose as to what the corresponding principles should be. Should one reapply the database approach principles one level up or should new methodologies be introduced? We show that new methodologies have appeared, defined specifically for the management of multiple autonomous databases. They lead to a new type of systems, called multidatabase systems or federated systems. These systems make databases interoperable, ie manipulable together in a non- procedural way, without global integration. They also preserve the autonomy of each database to satisfy first its own needs. Systems of that type will be of basic importance, especially for distributed databases and we analyze the corresponding reasons. We also present the methodologies proposed for their design and discuss their relationship. We further show that the evolution towards multidatabase systems is already on the way, as mapr commercial relational database systems are becoming of this type. We discuss their capabilities and limitations with respect to advanced prototypes. We also show industrial prototypes and the standardization issues. Finally, we present some research issues.
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    A Knowledge-based Prototype of a Factory Level CIM Systems.
    (1988) Harhalakis, George; Lin, Chang-Pin; Mark, Leo; ISR
    There is a critical need for establishing CIM at the factory level, to complement the research done in manufacturing integration, which has concentrated so far on flexible manufacturing cells, robotics and other fabrication and material handling devices. This paper identifies the application modules that clearly lend themselves to an integrated information flow in a controlled manner: Computer aided design and computer aided process planning constitute the product and process design centers of the proposed system respectively. Manufacturing resource planning undertakes the management of production plans to satisfy the market demand. The functional design of the system was derived from expertise in manufacturing management. The modeling and analysis are formalized with the use of generalized Petri-Nets. The implementation strategy recognizes the existence of application tools whose characteristics must be retained and subjected to synergism. Hence, a prolog-based database interoperability language enabled us to construct the knowledge- base that controls the system. Extensions of this work include the incorporation of a shop floor control module, to interface with the factory level.