Parallel-machine scheduling with deteriorating jobs and rejection

We consider several parallel-machine scheduling problems in which the processing time of a job is a (simple) linear increasing function of its starting time and jobs can be rejected by paying penalties. The objective is to minimize the scheduling cost of the accepted jobs plus the total penalty of the rejected jobs. Three variations of the scheduling cost are considered in this paper. The first is the makespan, the second is the total weighted completion time (for simple linear deterioration), and the third is the total completion time. For the former two problems, we propose two fully polynomial-time approximation schemes to solve them when the number of machines is fixed. For the last problem, we present an optimal O(n(2))-time dynamic programming algorithm when the deteriorating rates are equal for all jobs. (C) 2010 Elsevier B.V. All rights reserved.