Suh-Jenq Yang

Single-machine due-window assignment and scheduling with job-dependent aging effects and deteriorating maintenance

Due-window assignment and scheduling are important issues in modern manufacturing management. In this note we consider single-machine due-window assignment and scheduling with job-dependent aging effects and deteriorating maintenance. The objective is to find jointly the optimal time to perform maintenance, the optimal location and size of the due-window, and the optimal job sequence to minimize the total earliness, tardiness, and due-window related costs. We show that the problem can be optimally solved in O(n^4) time. We also show that a special case of the problem can be optimally solved by a lower order algorithm.

Single-machine group scheduling problems under the effects of deterioration and learning

This 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. Two models of learning for the job processing time are examined in this study. 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.

Unrelated parallel-machine scheduling with aging effects and multi-maintenance activities

Machine maintenance is often performed in manufacturing to prevent premature machine failures with a view to sustaining production efficiency. In this paper we study the parallel-machine scheduling problem with aging effects and multi-maintenance activities simultaneously. We assume that each machine may be subject to several maintenance activities over the scheduling horizon. A machine reverts to its initial condition after maintenance and the aging effects start anew. The objective is to find jointly the optimal maintenance frequencies, the optimal positions of the maintenance activities, and the optimal job sequences such that the total machine load is minimized. We apply the group balance principle to obtain the optimal positions of the maintenance activities and the number of jobs in each group in the scheduling sequence on each machine. We provide an efficient algorithm to solve the problem when the maintenance frequencies on the machines are given.

Two due date assignment problems with position-dependent processing time on a single-machine

The focus of this study is to analyze single-machine scheduling and due date assignment problems with position-dependent processing time. Two generally positional deterioration models and two frequent due date assignment methods are investigated. The objective functions include the cost of changing the due dates, the total cost of positional weight earliness, and the total cost of the discarded jobs that cannot be completed by their due dates. We conclude that the problems are polynomial time solvable. Significantly enough, after assessing the special case of each problem, this research found out that they can be optimally solved by lower order algorithms.

Single-machine scheduling problems simultaneously with deterioration and learning effects under deteriorating multi-maintenance activities consideration

Maintenance is important to manufacturing process as it helps improve the efficiency of production. Although different models of joint deterioration and learning effects have been studied extensively in various areas, it has rarely been studied in the context of scheduling with maintenance activities. This paper considers scheduling with jointly the deterioration and learning effects and multi-maintenance activities on a single-machine setting. We assume that the machine may have several maintenance activities to improve its production efficiency during the scheduling horizon, and the duration of each maintenance activity depends on the running time of the machine. The objectives are to determine the optimal maintenance frequencies, the optimal maintenance locations, and the optimal job schedule such that the makespan and the total completion time are minimized, respectively, when the upper bound of the maintenance frequencies on the machine is known in advance. We show that all the problems studied can be solved by polynomial time algorithms.

Parallel machines scheduling with simultaneous considerations of position-dependent deterioration effects and maintenance activities

This article considers identical parallel-machine scheduling problems with simultaneous considerations of position-dependent deterioration effects and maintenance activities. To counteract the deterioration effects on the machines, we assume that each machine must be maintained exactly once during the planning horizon and the maintenance can be scheduled immediately after completing the processing of any job. We further assume that, after the maintenance on a machine, the machine reverts to its initial condition and the deterioration effect starts anew. The objective is to find jointly the optimal maintenance positions and the optimal job sequences to minimize the total machine load. We provide polynomial time solutions for all the problems studied. Furthermore, we also show that the problem under study remains polynomially solvable when each machine is subject to multiple maintenance activities.

Unrelated parallel-machine scheduling problems with multiple rate-modifying activities

In this article we investigate scheduling problems with multiple rate-modifying activities on an unrelated parallel-machine setting. We assume that each machine may have multiple rate-modifying activities. The goal is to determine jointly the optimal rate-modifying activity frequencies, the optimal rate-modifying activity positions, and the optimal schedule to minimize the total completion time and the total machine load, respectively. If the number of machines is fixed, we propose two efficient polynomial time algorithms for solving both problems no matter what the processing time of a job scheduled after a rate-modifying activity is greater or less than its processing time scheduled before the rate-modifying activity.

Single-machine scheduling and slack due-date assignment with aging effect and deteriorating maintenance

We consider single-machine scheduling and slack due-date assignment problems simultaneously with the position-dependent aging effect and deteriorating maintenance. In order to counteract the aging effect on the machine, we assume that at most one maintenance is allowed throughout the planning horizon and the maintenance can be performed immediately after the processing of any job is completed. The maintenance duration is dependent on its starting time. The objective is to find jointly the optimal common slack time, the optimal maintenance position, and the optimal schedule such that the sum of the total earliness, the total tardiness, and the common slack time costs is minimized. We propose polynomial time algorithms for all the problems studied.

Decision support for unrelated parallel machine scheduling with discrete controllable processing times

A scheduling problem involving discrete controllable processing times is considered.The objectives are to minimize some scheduling criteria.We develop polynomial time algorithms for the considered problems.We further consider the NP-hard problem of the makespan case.An integer programming and a heuristic are presented to solve the NP-hard problem. In a manufacturing or service system, the actual processing time of a job can be controlled by the amount of an indivisible resource allocated, such as workers or auxiliary facilities. In this paper, we consider unrelated parallel-machine scheduling problems with discrete controllable processing times. The processing time of a job is discretely controllable by the allocation of indivisible resources. The planner must make decisions on whether or how to allocate resources to jobs during the scheduling horizon to optimize the performance measures. The objective is to minimize the total cost including the cost measured by a standard criterion and the total processing cost. We first consider three scheduling criterions: the total completion time, the total machine load, and the total earliness and tardiness penalties. If the number of machines and the number of possible processing times are fixed, we develop polynomial time algorithms for the considered problems. We then consider the minimization problem of the makespan cost plus the total processing cost and present an integer programming method and a heuristic method to solve the studied problem.

Single-Machine Scheduling Problems with Past-Sequence-Dependent Delivery Times and Position-Dependent Processing Times

This paper considers single-machine scheduling problems with job delivery times where the actual job processing time of a job is defined by a function dependent on its position in a schedule. We assume that the job delivery time is proportional to the job waiting time. We investigate the minimization problems of the sum of earliness, tardiness, and due-window-related cost, the total absolute differences in completion times, and the total absolute differences in waiting times on a single-machine setting. The polynomial time algorithms are proposed to optimally solve the above objective functions. We also investigate some special cases of the problem under study and show that they can be optimally solved by lower order algorithms.