Single‐machine scheduling jobs with exponential learning functions

In a manufacturing system workers are involved in doing the same job or activity repeatedly. Hence, the workers start learning more about the job or activity. Because of the learning, the time to complete the job or activity starts decreasing, which is known as ‘learning effect’. In this paper, an exponential sum‐of‐actual‐processing‐time based learning effect is introduced into single‐machine scheduling. By the exponential sum‐of‐actual‐processing‐time based learning effect, we mean that the processing time of a job is defined by an exponential function of the sum‐of‐the‐actual‐processing‐time of the already processed jobs. Under the proposed learning model, we show that under a sufficient condition, the makespan minimization problem, the sum of the θth (θ >0) power of completion times minimization problem, and some special cases of the total weighted completion time minimization problem and the maximum lateness minimization problem remain polynomially solvable.