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Discrete Dynamics in Nature and Society
Volume 2013 (2013), Article ID 916978, 10 pages
http://dx.doi.org/10.1155/2013/916978
Research Article

Heuristic for Stochastic Online Flowshop Problem with Preemption Penalties

Department of Industrial Engineering, Iran University of Science and Technology, Tehran 17347-93138, Iran

Received 20 May 2013; Accepted 26 August 2013

Academic Editor: Oswaldo Luiz do Valle Costa

Copyright © 2013 Mohammad Bayat et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The deterministic flowshop model is one of the most widely studied problems; whereas its stochastic equivalent has remained a challenge. Furthermore, the preemptive online stochastic flowshop problem has received much less attention, and most of the previous researches have considered a nonpreemptive version. Moreover, little attention has been devoted to the problems where a certain time penalty is incurred when preemption is allowed. This paper examines the preemptive stochastic online flowshop with the objective of minimizing the expected makespan. All the jobs arrive overtime, which means that the existence and the parameters of each job are unknown until its release date. The processing time of the jobs is stochastic and actual processing time is unknown until completion of the job. A heuristic procedure for this problem is presented, which is applicable whenever the job processing times are characterized by their means and standard deviation. The performance of the proposed heuristic method is explored using some numerical examples.