Integrating transportation in a multi-site scheduling environment

Multi-site scheduling deals with the scheduling problems of an enterprise with several distributed production sites, where sites are using the intermediate products of other sites to manufacture the products of the enterprise. Therefore the transportation of the raw materials and the intermediate products to the plants is an important task within the whole process of manufacturing. Scheduling problems are treated on two levels. On the global level, a global schedule is generated including the requirements for the local level schedulers which then have to transform the global schedule into a local schedule for manufacturing. Since transportation is a vital task in the multi-site scenario, we view it as a scheduling task on the local level as well. Besides the "classical" objectives of transportation tasks such as finding shortest paths or minimizing costs, the temporal restrictions of meeting the delivery dates here are the most important goals. We describe how transportation tasks can be modeled as a scheduling problem and which kind of solution strategies are appropriate.