*This research was supported by the National Science Council of the Republic of China (NSC77-041%EOl l-02). t Huan Neng Chiu is an Associate Professor of Industrial Management at the National Taiwan Institute of Technology. He received his Ph.D. from the graduate school. His research interests are in areas related to Inventory and Operations Management. STsong Ming Lin is a Professor of Industrial Management at the National Taiwan Institute of Technology. He received his Ph.D. from Clemson University in S.C;
U.S.A. Dr Lin has previously worked at Formosa Plastic Corporation Groups as a senior assistant to the president. He has a large number of publications;