A single-machine group schedule with fuzzy setup and processing times

Abstract

Group technology is a popular concept in production activities. It is assumed that all jobs are classified into several groups and the jobs within a group must be processed contiguously on the same machines. A sequence-independent setup time is incurred between two consecutive scheduling groups. Traditionally, both group setup times and job processing times have been assumed to be crisp numbers. This paper presents a single-machine groupscheduling problem when the group setup times and job processing times are treated as fuzzy numbers. A solution is provided to find a group sequence and a job sequence that minimizes the centroid values of these jobs. A total fuzzy flow time is then calculated for the decision makers. An example is given to illustrate this approach.

Keywords:

• Single machine
• group technology
• fuzzy setup time
• fuzzy flow time