MINIMIZING MAKESPAN WITH FUZZY PROCESSING TIMES UNDER JOB DETERIORATION AND LEARNING EFFECT

This paper proposes a single machine/processor scheduling problem consideringuncertain processing times under job deterioration and learning effect. In orderto express uncertainty of parameters such as processing times, effects ofdeterioration and learning, fuzzy numbers are used. The objective function in thisstudy is to minimize the makespan (maximum completion time) where theparameters of the problem are fully uncertain. In the literature, many singlemachine scheduling problems have been interested in deterministic modelparameters such as processing times, due dates and release dates. This studyintroduces a way for decision makers to cope with real life ambiguity andimprecision in single machine scheduling problems with uncertain processingtime under uncertain effects of job deterioration and learning. Due to complexityof the problem, most of constraints are non-linear. A numerical example isillustrated and a fuzzy mixed integer nonlinear programming model is proposedin this study.