Bicriterion scheduling problem in a job shop with parallel processors

This paper deals with the problem of bicriterion scheduling with parallel identical machines. An algorithm is proposed taking into consideration the following criteria: minimizing total flowtime (measure of inventory) and minimizing the maximum tardiness (measure of customer service). Five different dispatching rules are compared, namely, Shortest Processing Time (SPT), Earliest Due Date (EDD), Minimum Slack Time (MST), Largest Processing Time (LPT) and the sequence given by the algorithm of Wassenhove and Gelders. The Wassenhove and Gelders algorithm gives the best result among the dispatching rules. Finally, the proposed algorithm is applied to a real-life situation to illustrate and justify its validity.