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The work reported in this thesis is the culmination of a collaborative venture between Matra BAe Dynamics and the CIM Institute at Cranfield University. Initially the thesis examines the philosophy of the engineering doctorate, before describing the collaborating organisation's history and the background to the decision to formulate a structured process to aid information systems integration, including an appraisal of the perspective prior to the research. Following an extensive literature search of information systems and its integration, the findings from a survey of information systems in manufacturing organisations are described. These illustrate the need for a holistic modelling approach to aid information systems integration, the limitations of capital investment appraisal methods and the need to evaluate individual and multiple IS projects according to business objectives. The thesis then extends to the development of a process framework constituting three modules Audit, Assessment and Suggestion which provide a novel holistic approach to the problem of information systems integration. Following a review of modelling techniques, queuing models were selected to review the present engineering process through the creation of a theoretical model to benchmark performance of the information systems. Whilst linear goal programming models were utilised within the assessment module to optimise the multi-variable criteria involved in the selection of information system portfolios. The creation of financial scenarios based on corporate accounts and market limitations considered the implications of an information systems portfolio in conjunction with traditional investment appraisal methods to provide a comprehensive assessment of individual and multiple projects. The techniques used in this research were validated throughout and hence shown to exhibit criterion validity, whilst an industrial case study was undertaken to substantiate construct validity. Finally, recommendations for future work are presented and proposals for future developments outlined.

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This work addresses the problem of finding an improved solution to Computer Integrated Manufacturing (ClM) Architecture and Systems Design. The current approaches are shown to be difficult to understand and use, over complex. In spite of their complexity of approach they lack comprehensiveness and omit many factors and dimensions considered essential for success in today's competitive and often global market place. A new approach to ClM Architecture and Systems Design is presented which offers a simpler, more flexible and more robust format for defining a particular ClM System within a general architectural framework. At the same time this new approach is designed to offer a comprehensive and holistic solution. The research work involved the investigation of current approaches and research and development initiatives focusing particularly on the CIM-OSA and GRAI Integrated methodologies in the field of ClM Architecture. The strengths and weaknesses of the various approaches are examined. Developments in other related fields including manufacturing systems, manufacturing management, information technology and systems generally have been investigated regarding their relevance and possible contribution to an improved solution. The author has built on his practical experience in creating, designing and managing the implementation of a global CIM system. The authors work on several publicly funded collaborative research and development projects relevant to the problem area is described. These include CIM-OSA, IMOCIM and TIQS projects. In the latter two projects the author was instrumental in developing the methodological approach based on a systems approach to business processes in connection with the design of quality and manufacturing systems. Both of these projects have contributed to this work. The author has also participated in the global IMS programme as a rapporteur for the European Commission and this helped to provide a global perspective on the problems of manufacturing companies as they attempt to compete in a world wide market place. The results of this work provide the basis for a radically improved approach to ClM Architecture and Systems Design based on the holistic view of an enterprise. The approach developed supports the business process view of an enterprise; addresses the people and organisational aspects; leads to ClM solutions focused on meeting enterprise goals; and is able to deal with a significantly increased scope and complexity compared with existing methods yet is easily understood and more simple to simple to apply than current approaches.

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Discrete linear control theory is used in this research to examine the effects of system choice and data errors on the performance of production control systems. Two common information flow systems are modelled. These are the Reorder Cycle (ROC) and the Material Requirements Planning (MRP) systems. System choices include the choice of forecasting method, the choice of delivery policy, and the choice of inventory rule. The source of data errors include stock recording errors, delay in stock recording, incorrect bills of material. The other part of the research examines the sequence of implementing a new production control system. Different ways of moving from a Reorder Cycle to a Material Requirements Planning system are studied. Guidelines for an implementation sequence are produced.

This thesis relates to the area of short term scheduling and control in batch process plants. A batch process plant consists of individual plant items linked by a pipe network through which product is routed. The structure of the network and the valve arrangements which control the routing severely constrains the availability of plant items for configuration in routes when a plant is operating. Current approaches to short term scheduling contain simplifying assumptions which ignore these constraints and this leads to unrealistic and infeasible schedules. The work undertaken investigates the use of techniques from the areas of Artificial Intelligence (AI) and Discrete Event Simulation (DES) in order to overcome these simplifying assumptions and develop good schedules which can be implemented in a plant. The main divisions of work cover a number of areas. The development of a representation scheme for batch plant networks, and procedures for reasoning about the constraints imposed by their structure to infer the actual availability of plant items for routing purposes at any time. The development of a dynamic rule-based route configuration procedure which takes into account the constraints on plant item availability. The development of an activity scheduling framework for batch plants based on this. The development of a dynamic simulation model to take account of finite capacity constraints in a batch plant. The integration of these elements in a hybrid structure to make best use of the techniques available from the areas of AI and DES. The representation scheme and procedures developed for reasoning about the constraints in a plant network enable the simplifying assumptions of other approaches to be overcome so that the system can produce good feasible schedules. The hybrid structure is a practical one to take for implementation and enables the best use of techniques from AI and DES.

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