A bilevel programming approach to assembly job shop scheduling

A bilevel programming approach for assembly job shop scheduling is proposed. Two levels of decision makers are identified in the model. The first level is the project manager and the second level is the shop floor manager. The first level aims to minimize the earliness and tardiness of completed jobs. The second level aims to minimize the average shop floor throughput time. Because their aims may conflict, these levels optimize their own objectives based on a non-cooperative game playing process. Their decision variables are denoted by order release mechanisms and dispatching rules respectively. Using a simulation approach, this paper identifies the best choice for the project manager under different job shop utilization levels. The research findings can provide managerial guidance to the project manager as which order release mechanisms to use in order to optimize his objective.