The traditional focus of scheduling research is on finding schedules with a low implementation cost. However, in many real world scheduling applications finding a robust or flexible schedule is just as important. A robust schedule is a quality schedule expected to still be acceptable if something unforeseen happens, while a flexible schedule is a quality schedule expected to be easy to change. ...

This paper surveys the literature related to solving traditional unrelated parallel-machine scheduling problems. It compiles algorithms for the makespan, total weighted sum of completion times, maximum tardiness, total tardiness, total earliness and tardiness, and multiple criteria performance measures. The review of the existing algorithms is restricted to the deterministic problems without se...

Dispatching rules are widely used to dynamically schedule the operations in a shop. Their efficiency depends on the performance criteria of interest. One of the most important objectives to deal with in a manufacturing system is the tardiness which can be measured through several performance measures. This paper proposes an effective procedure to estimate the first two central moments (i.e., th...

We use the Akers-Friedman geometric approach to solve the two jobs job-shop problem when there is an earliness cost on the first operation and a tardiness cost on the last operation of each job. We then generalize the problem by imposing earliness and tardiness costs on each operation and finally, we solve it using a dynamic programming algorithm. KeywordsEarliness-tardiness scheduling, Polyn...

In many manufacturing systems, jobs that are completed early are held as finished-goods inventory until their due-dates, and hence we incur earliness costs. Similarly, jobs that are completed after their due-dates incur penalty. The objective in such situations would, therefore, be to meet the due-dates of the respective jobs as closely as possible, and consequently minimize the sum of earlines...

Total weighted tardiness is a measure of customer satisfaction. Minimizing it represents satisfying the general requirement of on-time delivery. In this research, we consider an ant colony optimization (ACO) algorithm to solve the problem of scheduling unrelated parallel machines to minimize total weighted tardiness. The problem is NP-hard in the strong sense. Computational results show that th...

In this article, we consider the minimization of the total tardiness in a flexible job-shop. In our knowledge, this criterion is not previously studied for this type of shop configuration. The total tardiness criterion was mainly considered in the single machine problem (Chu [Chu92] and Souissi et al. [SKC04]). Few references studied this criterion in a job-shop configuration. The priority rule...

Scheduling problems involving both earliness and tardiness costs became more important in recent years. This kind of problems include both earliness and tardiness penalties and tries to reduce them. In this study a case study from real world is investigated. Since the machine is bottle neck in the production line and all jobs have a common restrictive due date and different earliness and tardin...

The objective of this paper is to propose a scheduling problem for multiple automated guided vehicles (AGVs) in a manufacturing system. Considering the due date of AGVs requiring for material handling among shops in a job shop layout, their earliness and tardiness are significant in satisfying the expected cycle time and from an economic view point. Earliness results in AGVs waiting and tardine...

Two optimal algorithms, MTA* and MT-RBA*, are presented to find the optimal yard crane (YC) job sequence for serving a fleet of vehicles for delivery and pickup jobs with scheduled deadlines and predicted vehicle arrival times. The objective is to minimize the total tardiness of incoming vehicle jobs. This is important for minimizing vessel turnaround time. In the search for an optimal job sequ...