We solve a due-window assignment problem on parallel identical machines. In addition to the standard objective of finding the optimal job schedule, in due-window assignment problems one has to assign a time interval during which goods are delivered to customers with no cost. Jobs scheduled prior to or after the due-window are penalized according to their earliness/tardiness value. We assume that jobs have identical processing times, but may have job-dependent earliness and tardiness costs (eg, due to possible different destinations). We show that the problem can be reduced to a non-standard asymmetric assignment problem, and introduce an efficient (O(n4)) solution procedure.
scheduling parallel machines earliness–tardiness due-window assignment problem