In a general purpose shipterminal ships arrive in order to be loaded, unloaded or both. The terminal has only a limited number of berth places, and ships arriving when all berths are occupied are lost to competiting firms. By hiring extra manpower capacity ships can be served faster and leave earlier, so that fewer ships will be lost. The size of a detailed model will be tremendous. Therefore we have chosen for an iterative aggregation-disaggregation approach in which optimization alternates with simulation and adaptation of the model.
For this specific problem the method performs quite well, and we think it to be useful in other situations as well.