Abstract
We study practical scheduling problems with a major decision referring to the number of machines to be used. We focus on a two-stage flexible flowshop, where each job is processed on the first (critical) machine, and then continues to one of the second-stage parallel machines. Jobs are assumed to have identical processing times, and are processed in batches. A setup time is required when starting a new batch. We consider two objective functions: minimum makespan and minimum flowtime. In both cases, a closed form expression for the optimal number of machines to be used is introduced, and a unique and unusual sequence of decreasing batch sizes is shown to be optimal.
Original language | English |
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Pages (from-to) | 199-210 |
Number of pages | 12 |
Journal | Journal of Scheduling |
Volume | 17 |
Issue number | 2 |
DOIs | |
State | Published - Apr 2014 |
Bibliographical note
Funding Information:Acknowledgments This paper was supported in part by The Recanati Found of the School of Business Administration, and by The Charles Rosen Chair of Management, The Hebrew University, Jerusalem, Israel.
Keywords
- Deterministic
- Flowshop
- Flowtime
- Makespan
- Scheduling
- Sequencing