This study investigates single-machine due-date assignment and scheduling problems with a job-dependent aging effect under a deteriorating maintenance activity consideration simultaneously. The maintenance activity can be scheduled immediately after any one of the jobs has been completed. In order to model the problem more realistic, we assume that: (1) once the maintenance activity has been co...

This article considers the parallel machine scheduling problem with step-deteriorating jobs and sequence-dependent setup times. The objective is to minimize the total tardiness by determining the allocation and sequence of jobs on identical parallel machines. In this problem, the processing time of each job is a step function dependent upon its starting time. An individual extended time is pena...

Potential workers are classified as unemployed if they seek work but not working. The population contains two groups—those with jobs and those without jobs. Those on furlough or temporary layoff. This group expanded tremendously in April 2020, at the trough of pandemic recession. They wait out periods non-work understanding that their still exist will be recalled. We show resulting temporary-la...