A PROJECT-ORIENTED PRODUCTION-MODEL OF BATCH PLANTS

This paper presents a project-oriented framework for interactive analy sis of the feasible plans and schedules that can provide an effective/ efficient flow of orders within a batch process. The proposed approach is based on a hierarchical project-oriented production model that int egrates production planning with short-term scheduling and resource le veling, At the highest layer of the hierarchy, the use of aggregate ac tivities and their milestone dates is aimed to emphasize a management perspective of the production model. As a core element of the model a process task network is used. Each node of this network is expanded fu rther into sub-tasks and their detailed schedules. Efficiency in resou rce's usage during short-term scheduling is improved by changing proce ss task durations. The implementation of the project-oriented producti on planning methodology has been based on the existing literature in p roject management (Leachman, 1982, Leachman, 1983; Hackman and Leachma n, 1989), but many alternative techniques can be used for specific lay ers (sub-problems) of the proposed hierarchy. An attractive feature of the project oriented approach is that descentralized decision making is favored. Conflicts between management objectives and shop-floor dec isions are solved iteratively in a two-tier scheme. Simple examples ar e considered to illustrate the potentials and advantages of the projec t-oriented approach. (C) 1998 Elsevier Science Ltd. All rights reserve d.