Scheduling Problems With Effects Of Learning And Deterioration

In many realistic situation, a job processed later consumes more time than the same job when it is processed earlier, this phenomenon is known as deteriorated effect. The skills of workers continuously improve when repeating the same or similar tasks, lead to processing time is shorter, this phenomenon is as the learning effect in the literature. There are situations where both the deterioration and learning effects might exist at the same time.In recent years, there are many literatures about machine scheduling problems with general effects of learning or deterioration, the machine scheduling problem of learning and job deterioration co-exist also received more attention. This paper introduces a general scheduling model with the effects of learning and deterioration simultaneousl for single machine scheduling problems, under the proposed model, the actual processing time of a job depends not only on the start time of the job and its scheduled position, but also on the length and the position of the already scheduled jobs. It shows that the addressed problem remains polynomially solvable for the objectives, i.e., minimize the makespan Cmax, minimization of the total completion time∑C minimization of the total weighted completion time∑wjCj, the maximum lateness Lmax, and the maximum tardiness Tmax. Then the paper investigates single-machine group scheduling problems with simultaneous considerations of deteriorating and learning effects to minimize the makespan and the total completion time of all jobs. The group setup time is assumed to follow a simple linear time-dependent deteriorating model. We provided polynomial time solutions for the makespan minimization problems. We also showed that the total completion time minimization problems remain polynomially solvable under agreeable conditions.