Heuristic optimization strategies for scheduling of manufacturing processes

Discrete Event Simulation (DES) is a suitable method for scheduling manufacturing processes, particularly in the case of finite capacity resources. In practice mostly special dispatching rules are used for optimizing the process. In addition several heuristic optimization algorithms were developed to get better results by changing control variables in connection with repeated simulation runs. In a manufacturing process the most important control variables are permutations (of jobs, priorities etc.). The convergence behavior of the algorithms strongly depends on the distance measurement in the control space because this decides about the increment of the search steps. Some special distance measurements for permutations are developed and they are investigated for diverse structures of manufacturing systems, such as flowshops and jobshops.