Multi-objective scheduling with fuzzy due-date

In this paper, we examine the characteristic features of multi-objective scheduling problems formulated with the concept of fuzzy due-date. By computer simulations, we show that various scheduling criteria can be expressed by modifying the shape of membership functions of fuzzy due-dates. We also show the difficulty in handling the minimum satisfaction grade as a scheduling criterion. This difficulty is caused by the fact that the minimum satisfaction grade is zero for almost all schedules. This makes many search algorithms inefficient. We suggest an idea to cope with this difficulty. (C) 1998 Elsevier Science Ltd. All rights reserved.