Job sequencing with fuzzy processing times

AbstractIn practice, processing times can be more accurately represented as intervals with the most probable completion time somewhere near the middle of the interval. A fuzzy number which is essentially a generalized interval can represent this processing time interval exactly and naturally. In this work, triangular and trapezoidal fuzzy numbers are used to represent those vague job processing times in job shop production systems. The job sequencing algorithms of Johnson and Ignall and Schrage are modified to accept fuzzy job processing times. Fuzzy makespans and fuzzy mean flow times are then calculated for greater decision-making information. Numerous examples are used to illustrate the approach