An agent-based approach to modelling virtual enterprises

This paper describes how virtual enterprises (VEs) can be modelled using the AGORA multi-agent architecture, designed for modelling and supporting cooperative work among distributed entities. The model consists of a structure of AGORAs and agents, where AGORAs are facilitators of cooperative work for agents and the agents represent the partners of the VE, the cooperative mechanisms and the service providers. The distributed and goal-oriented nature of the VE provides a strong motivation for the use of agents to model VEs. The main advantages of this approach are that the structure of AGORAs provides a homogeneous modelling environment throughout the life cycle of the VE, traceability of the VE activities and a history of the VE. In addition to these, it is important to point out that, agents being computational entities, the resulting model provides an easy and efficient passage from the model to the computational support that is required by the VE.     

An expert system for a semiconductor manufacturing environment

We developed an expert system to analyse and suggest solutions to problems commonly encountered in the production of integrated circuits. We wrote a PC-based program to implement the expert system. Our goal is to enable interested readers to relate some of the accomplishments realized by a high tech manufacturing company to their own production, manufacturing or maintenance environment. We discuss the difficulties encountered when implementing an expert system as well as the great benefits derived from its use.     

A modelling approach for production costing and continuous improvement of manufacturing processes

It is shown how production management constraints can be taken into account as early as the design stage of the product. It is then shown that the indication of physical and economic performances is a means to obtain integration and to continually improve the manufacturing processes. To perform continuous and efficient evaluation of physical and economic performances, the concept of activity is introduced, now acknowledged as a basic concept of cost management systems. A modelling approach is then proposed to allow each member of the design team, in a concurrent engineering context, to perform activity based modelling and estimations with simulation. After describing the set of possible situations in which this approach can be used, an application case is presented concerning a French firm, and the advantages and disadvantages of the approach are discussed.     

Integrated enterprise modelling: A method for the management of change

'The capability to adjust to new conditions quickly has developed into a decisive competitive advantage. You cannot waste any time if you want to be successful.' (Emeritus Professor Dr h. c. mult. Changing conditions in the market place issue new challenges to small- and medium-sized enterprises. Organization and qualification of employees have to be adjusted to the modified situation. If the only steady factor is change, the management of change is going to be the outstanding role of the leader. The successful structuring of change processes requires powerful methods and tools: to make business processes transparent and lean; to find a common 'corporate language' based upon customers benefits and shareholders value; Dr-Ing. G. Spur) to bring together process know-how in a central information base. This contribution summarizes the experiences from several projects. We will show how the synchronization of necessary reengineering measures makes corporate knowledge active, e.g. to improve the shareholders value, reduce investment costs, and shorten the duration of projects. As successful examples two medium-sized companies are described.     

Automated simulation modelling and analysis for manufacturing systems

Simulation is extensively used as a basis for the analysis and design of manufacturing systems. It has been steadily increasing in popularity due to the simplicity and ease of model understanding even by the non-simulationist. The popularity of simulation is also due to recent developments of easy-to-use simulation software. Simulation generators represent a significant trend in this direction. More recent developments include simulation expert systems both from the viewpoint of modelling and also statistical output analysis. The work that has been explained herewith is based on one such simulation generator that has been developed at the Center for Manufacturing Productivity and Technology Transfer at Rensselaer Polytechnic Institute. This system, RENSAM (RENssclaer Simulator for Automated Manufacturing) is an adaptive simulation generator and has an underlying structure that represents a FMS. The research that has been accomplished is the result of the constant efforts that are being undertaken to make RENSAM a complete decision making tool. In order to achieve what is envisioned, output analysis, optimization and sensitivity analysis routines have been added to the generic simulation and intelligent front end (IFE), The output analysis routine determines the experimental conditions under which the simulation is executed. The optimization routine searches for the optimal values for the parameters of interest and then sensitivity analysis is used to examine the relationship among various parameters. The sensitivity analysis that is presented has been developed taking into account various methodologies in this field.     

Classification hierarchies for product data modelling

Abstraction is an essential element in data modelling that appears mainly in one of the following forms: generalisation, classification or aggregation. In the design of complex products classification hierarchies can be found product families that are viewed as classes of product types, while product types are seen as classes of product instances. So far data models, if they support levels of classification, do not support the inheritance of product properties the way product family hierarchies are supposed to. This paper proposes an interpretation of the member of construct that enables one to define inheritance in classification hierarchies. Unified modelling language (UML) static structures are used as data modelling language. A textual notation is added that enables the introduction of data structures and corresponding data contents in the course of an analysis.     

Application of load-oriented manufacturing control in industry

This paper deals with multi-stage lotsizing models for imperfect production processes. The effect of imperfect quality on lotsizing decisions and effect ofinspection errorsare taken into consideration in the proposed models. Numerical examples are presented for illustration purposes. The developed models are very helpful for justifying quality assurance and quality improvement efforts.     

Job sequencing to minimize tool changeovers in flexible manufacturing systems

The combination of group technology and heuristic is used to schedule jobs on a machine equipped with an automatic tool changer (ATC). The problem is prominent in flexible manufacturing systems where the efficiency in operation is, in part, obtained by use of ATC. The procedure presented here is efficient and does not require complex mathematics.     

An Information-Maximizing Interactive Procedure for Scenario Probability Elicitation

Various approaches have been proposed for determining scenario probabilities to facilitate long-range planning and decision making. These include microlevel approaches based on the analysis of relevant underlying events and their interrelations and direct macrolevel examination of the scenarios. The determination of a unique solution demands excessive consistency and time requirements on the part of the expert and often is not guaranteed by these procedures. We propose an interactive information maximizing scenario probability query procedure (IMQP) that exploits the desirable features of existing methods while circumventing their drawbacks. The approach requires elicitation of cardinal probability assessments and bounds for only marginal and first-order conditional events, as well as ordinal probability comparisons (probability orderings or rankings) of carefully selected scenario subsets determined using concepts of information theory. Guidelines for implementation based on simulation results are also developed. A goal program for handling inconsistent ordinal probability responses is also integrated into the procedure. The results of behavioral experimentation (which compared our approach to Expert Choice and showed that the IMQP was viable) compared favorably in terms of ease of use and time requirements, and works best for problems with a large number of scenarios. Design modifications to IMQP learned from the experiments, such as incorporating interactive graphics, are also in progress.     

An Empirically Derived Model for the Adoption of Customer-based Interorganizational Systems*

Information systems (IS) researchers are now calling for the need to draw from the empirically rich field of organizational innovation. As the impact of strategic systems is increasingly being felt by organizations, the view that these systems are innovations or innovative uses of technology is becoming prevalent. Customer based interorganizational systems (CIOS) represent one of the most prominent types of such systems. This research investigates CIOS adoption. A model is constructed based on significant studies in innovation to identify factors facilitating the adoption decision of a CIOS. Data are gathered from 226 senior executives. Discriminant analysis is used to identify factors that distinguish adopters from nonadopters. Factor analysis of significant variables yielded a parsimonious model of CIOS adoption. The five factor model includes (1) a proactive technological orientation and (2) an internal push for the system as the two most significant sets of facilitators. Implications for research and practice are then discussed.     

Developing a manufacturing vision

The concept of a manufacturing vision is introduced as a company specific, commonly shared, holistic picture of the way in which future manufacturing in the company will function. First is presented what a manufacturing vision is, and then is presented a five-step framework in which such a manufacturing vision may be developed. A manufacturing vision is regarded as a bridge between the mission, goals, and strategies of an industrial enterprise and the detailed design of a manufacturing system. Such a bridge may ensure that manufacturing is able to make a relevant strategic contribution to developing and sustaining the competitiveness of the company and may serve as a guide for innovation and integration of the various elements of a manufacturing system. The paper rests on action research projects in more than ten industrial companies, and the experiences gained are discussed in a section on issues related to the development process including experimentation without fear of losing face, participation and involvement of managers and employees, and finally the outset for a manufacturing vision. To give an example of a manufacturing vision the paper also very briefly introduces a case of a medium-sized supplier of welded parts and equipment for a number of different industries.     

Evaluation of scheduling strategies for a dynamic job shop in a tool-shared,flexible manufacturing environment

A two-phase approach is used to examine the impact of job scheduling rules and tool selection policies for a dynamic job shop system in a tool-shared, flexible manufacturing environment. The first phase develops a generalized simulation model and analyses 'simple' job scheduling rules and tool selection policies under various operating scenarios. The results from this investigation are then used to develop and analyse various bi-criteria rules in the second phase of this study. The results show that the scheduling rules have the most significant impact on system performance, particularly at high shop load levels. Tool selection policies affect some of the performance measures, most notably, proportion of tardy jobs, to a lesser degree. Higher machine utilizations can be obtained at higher tool duplication levels but at the expense of increased tooling costs and lower tool utilization. The results also show that using different processing time distributions may have a significant impact on shop performance.     

Effect of tool sharing on the reliability of flexible manufacturing systems

A manufacturer invests on FMS to enhance the availability of resources in order to maintain uninterrupted production. Tool failures pose a major obstacle to this objective. In this paper, a mathematical model has been developed to determine the spares requirement of the tooling system in FMS, so that a desired tooling system reliability is achieved while overall tooling cost is minimized. The influence of tool sharing on cost, reliability, spares requirement and tool magazine capacity of the FMS are analysed. The tools and tool transporter are subject to general failure distributions.     

Cloud manufacturing system for sheet metal processing

Abstract

Cloud computing is changing the way industries and enterprises run their businesses. Cloud manufacturing is emerging as an approach to transform the traditional manufacturing business model, while helping the manufacturer to align production efficiency with its business strategy, and creating intelligent factory networks that enable collaboration across the whole enterprise. Many production planning and control (PPC) problems are essentially optimisation problems, where the objective is to develop a plan that meets the demand at minimum cost or maximum profit. Because the underlying optimisation problem will vary in the different business and operation phases, it is important to think about optimisation in a dynamic mechanism and in a number of interlinked sub-problems at the same time. Cloud manufacturing has the potential to offer decision support as a service and medium of communication in PPC. To solve these problems and produce collaboration across the supply chain, this paper provides an overview of the state of the art in cloud manufacturing and presents a model of cloud-based production planning and production system for sheet metal processing.     

An Examination of Two Screen/Report Design Variables in an Information Recall Context*

Screen/report design for output organization is still very much a common sense-driven activity. This paper identifies a preliminary set of factors beyond display format for examination as screen/report design variables. A laboratory experiment was conducted to assess the influence of one of these factors, spatial layout of information, along with display format in an information recall context. Individual imagery orientation (verbalizer/visualizer) was used as a moderating variable in the experimental design. The findings indicate that spatial layout of information significantly influenced performance when the recall task involved pattern detection. In fact, a central location of data in a document was the most conducive to pattern recall performance. Further, terminal items facilitated pattern recall better than early input items. With respect to display format, the results support previous findings that a tabular display enhances performance for point-value recall tasks while graphs exhibit an edge over tables for pattern types of recall tasks. Overall, the verbalizers demonstrated a complete supremacy in performance. Interaction between individual imagery orientation and display format indicates that, while the verbalizers and the mixed type were immune to display format variations, the graphical stimulus enhanced the pattern recall performance of the visualizers.     

Manufacturing management strategies for environmental protection: Toward the environmental upgrading of management and manufacturing systems to cope with environmental laws

Recent environmental problems have been caused by business activities and a lifestyle based on mass production, mass consumption and mass disposal. These problems have also become global in scale. Increasingly, global efforts are being applied to preserve and improve the environment. NEC, a worldwide electronics manufacturer, created its own environment action plan called Eco-Action 21. This is a continuously evolving plan applied throughout the NEC group and subsidiaries. Globally, 34 NEC manufacturing sites have received ISO 14001 certification. NEC Tohoku in Japan and NEC Ireland obtained BS 7750 certification even before this. NEC improves subcontractors' environmental behaviour with our accumulated expertize and technology derived from our ISO experience and our own development. Input for this paper was not only from NEC Tohoku and the NEC group, but also from outside NEC.     

Integrated procurement- production system in a just-in-time environment-modelling and analysis

Classically, economic lot size models have been used separately for procurement and production subsystems. However, when the raw materials are used in production, the procurement policies are dependent on the schedule and the batch size for the product. Hence, it is necessary to unify the procurement and production policies. The just-in-time JIT environment provides an ideal setting for such a coordination between the procurement and production policies. The model proposed here is a traditional inventory model recast into a model for a JIT system for a single product, multistage batch environment aiming at the minimization of total variable cost and thereby determining the batch sizes for the product and raw material order sizes. A JIT system aims at minimizing setup time and this feature is captured in the proposed model. The computational experience reported in this paper is based on a number of simulated problem sets. The possible domain of application is also highlighted.     

A modelling system for local government resource planning

A major problem in local government is how to maximise the effectiveness of resource allocation. Senior officers and members concerned with corporate and strategic issues must take account of contemporary information of considerable variety and combine this with estimates of the future in their attempts to achieve rational resource allocation. This article describes the development of an experimental computer based corporate modelling system at Clwyd County Council which was designed to support allocation decisions pertaining to a 5 year planning period. It is concluded that a firm basis was achieved for progress towards a comprehensive operational system.     

A computer-based modelling system for electric utility planning

This paper examines the development of a computer based modelling system for electricity planning within the South African Electricity Supply Commission. The system is a specialized computer based planning system, which enables the extensive analysis of a wide variety of problems to be undertaken.

This paper explains the methodology and progress of analysis through the system and describes in detail how the planners can progress from forecasting of demand and supply parameters to the proposals for a necessary expansion of generation, transmission and distribution facilities. Finally, the paper explains the analysis required to verify the proposed projects feasibility from the point of view of corporate financing.