Reformulation of various non-fuzzy scheduling problems using the concept of fuzzy due-date

In this paper, we show how nonfuzzy scheduling problems can be reformulated in the framework of fuzzy due-date. The membership function of a fuzzy due-date assigned to each job shows the human user´s satisfaction grade for the completion time of that job. We first describe the concept of the fuzzy due-date. Next we show that various scheduling criteria can be represented in terms of the members function of the fuzzy due-date assigned to each job. That is, we show that many nonfuzzy scheduling problems can be reformulated through the concept of the fuzzy due-date. Then we show how we can combine various scheduling criteria into a single measure. The similarity and the difference between conventional scheduling problems and fuzzy scheduling problems are illustrated by computer simulations on several numerical examples