A best possible deterministic on-line algorithm for minimizing makespan on parallel batch machines

  • Authors:
  • Peihai Liu;Xiwen Lu;Yang Fang

  • Affiliations:
  • School of Science, East China University of Science and Technology, Shanghai, People's Republic of China 200237;School of Science, East China University of Science and Technology, Shanghai, People's Republic of China 200237;School of Science, East China University of Science and Technology, Shanghai, People's Republic of China 200237

  • Venue:
  • Journal of Scheduling
  • Year:
  • 2012

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Abstract

We study on-line scheduling on parallel batch machines. Jobs arrive over time. A batch processing machine can handle up to B jobs simultaneously. The jobs that are processed together form a batch and all jobs in a batch start and are completed at the same time. The processing time of a batch is given by the processing time of the longest job in the batch. The objective is to minimize the makespan. We deal with the unbounded model, where B is sufficiently large. We first show that no deterministic on-line algorithm can have a competitive ratio of less than $1+(\sqrt{m^{2}+4}-m)/2$ , where m is the number of parallel batch machines. We then present an on-line algorithm which is the one best possible for any specific values of m.