Institute for Systems Research
Permanent URI for this communityhttp://hdl.handle.net/1903/4375
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Item Manufacturing Cell Formation Under Random Product Demand(1993) Harhalakis, George; Minis, Ioannis; Nagi, R.; ISRThe performance of cellular manufacturing systems is intrinsically sensitive to demand variations and machine breakdowns. A cell formation methodology that addresses, during the shop design stage, system robustness with respect to product demand variation is proposed. The system resources are aggregated into cells in a manner that minimizes the expected inter-cell material handling cost. The statistical characteristics of the independent demand and the capacity of the system resources are explicitly considered. In the first step of the proposed approach the expected value of the feasible production volumes, which respect resource capacities, are determined. Subsequently, the shop partition that results in near optimal inter cell part traffic is found. The applicability of the proposed approach is illustrated through a comprehensive examples.Item 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.; ISRThis 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 approachesItem UPN: A Petri Net Based Graphical Representation of Company Policy Specifications in CIM(1992) Harhalakis, George; Lin, Chang-Pin; ISRA 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.Item INformation Systems for Integrated Manufacturing (INSIM)(1992) Harhalakis, George; Lin, Chang-Pin; Mark, Leo; ISRA 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.Item Hierarchical Modeling Approach for Production Planning(1992) Harhalakis, George; Nagi, R.; Proth, J.M.; ISRProduction 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.Item Implementation of Rule Based Information Systems for Integrated Manufacturing(1992) Harhalakis, George; Lin, Chang-Pin; Mark, Leo; Muro-Medrano, P.R.; ISRThis 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.
Item Some Open Problems in the Design and Use of Modern Production Systems(1992) Harhalakis, George; Proth, J.M.; ISRDuring 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.Item A PDES Model for Microwave Modules(1991) Bahadur, Sudhanshu; Harhalakis, George; Hosier, Robert N.; Minis, Ioannis; ISRThis 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.Item INformation Systems for Integrated Manufacturing (INSIM) - A Design Methodology(1991) Harhalakis, George; Lin, Chang-Pin; Mark, Leo; Muro, P.R.; ISRFull 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.Item Formal Representation, Verification and Implementation of Rule Based Information Systems for Integrated Manufacturing(1991) Harhalakis, George; Lin, Chang-Pin; Mark, Leo; Muro, P.R.; ISRFull 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.