Flexible flowshop scheduling with equal number of unrelated parallel machines

Subject Areas : Mathematical Optimization

L Mahdavi ¹ , V Zarezadeh ² , P Shahnazari-Shahrezaei ³

1 - Associate Professor, Dep. of Industrial Engineering, Mazandaran University of Science and Technology, Babol, Iran
2 - M.Sc., Dep. of Industrial Engineering, Mazandaran University of Science and Technology, Babol, Iran
3 - Ph.D. Student, Dep. of Industrial Engineering, Firoozkooh Branch, Islamic Azad University, Firoozkooh, Iran

Received: 2015-05-18 Accepted : 2015-05-18 Published : 2011-03-01

Keywords: Flexible Flowshop, makespan, Unrelated machines,

Abstract :

This article addresses a multi-stage flowshop scheduling problem with equal number of unrelated parallel machines. The objective is to minimize the makespan for a given set of jobs in the system. This problem class is NP-hard in the strong sense, so a hybrid heuristic method for sequencing and then allocating operations of jobs to machines is developed. A number of test problems are randomly generated and results obtained by proposed heuristic are compared with optimal solutions reported by the Lingo 8.0 package applying the branch & bound approach. The results show that the proposed hybrid method is more efficient when the problem sizes have been increased.