Two results in a recent paper by Wang and Cheng [Wang, J-B and TCE Cheng (2007). Asia-Pacific Journal of Operational Research, 24, 245–261] are incorrect because job processing times are variable due to both deteriorating jobs and learning effects, which is not taken into account by the...

We consider single-machine scheduling problem in which the processing time of a job is a function of its position in a sequence, its starting time, and its resource allocation. The objective is to find the optimal sequence of jobs and the optimal resource allocation separately. We concentrate on...