Article ID: | iaor200972093 |
Country: | United States |
Volume: | 40 |
Issue: | 4 |
Start Page Number: | 478 |
End Page Number: | 493 |
Publication Date: | Apr 2008 |
Journal: | IIE Transactions |
Authors: | Billaut Jean-Charles, Gribkovskaia Irina, Strusevich Vitaly |
We consider the problem of scheduling families of jobs in a two-machine open shop so as to minimize the makespan. The jobs of each family can be partitioned into batches and a family setup time on each machine is required before the first job is processed, and when a machine switches from processing a job of some family to a job of another family. For this NP-hard problem the literature contains (5/4)-approximation algorithms that cannot be improved on using the class of group technology algorithms in which each family is kept as a single batch. We demonstrate that there is no advantage in splitting a family more than once. We present an algorithm that splits one family at most once on a machine and delivers a worst-case performance ratio of 6/5.