• Journal of Korean Institute of Industrial Engineers
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• v.35 no.4
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• pp.257-265
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• 2009

This paper considers the hybrid flow shop scheduling problem for the objective of minimizing the number of tardy jobs. In hybrid flow shops, each job is processed through multiple production stages in series, each of which has multiple identical parallel machines. The problem is to determine the allocation of jobs to the parallel machines at each stage as well as the sequence of the jobs assigned to each machine. Due to the complexity of the problem, we suggest search heuristics, tabu search and simulated annealing algorithms with a new method to generate neighborhood solutions. In particular, to evaluate and select neighborhood solutions, three surrogate objectives are additionally suggested because not much difference in the number of tardy jobs can be found among the neighborhoods. To test the performances of the surrogate objective based search heuristics, computational experiments were performed on a number of test instances and the results show that the surrogate objective based search heuristics were better than the original ones. Also, they gave the optimal solutions for most small-size test instances.

• Journal of the Korea Society for Simulation
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• v.4 no.1
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• pp.75-86
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• 1995

There has been a great deal of interest in the area of group technology recently. They suggest that group technology's formation of cells of machines which are dedicated to production of families of parts will bring many of the advantages of cellular layout of job shops. In this context, Yoon [2] designed and suggested 3 types of the layout structure for a small firm, by introducing the cellular layout into the traditional flow line of an existing factory. Also he found that P5C, i.e. process layout /5 cells layout, outperformed the rest types. However, he performed the experiments in the standpoint of the existing factory operation and did not consider other operating methods including changing the dispatching and sequencing rules. Therefore, in this paper, we compared the performance of 3 different layout by the simulation technique using the real data from the existing factory, considering a newly suggested dispatching and machine selection rule.