Operations Research Transactions ›› 2020, Vol. 24 ›› Issue (4): 107-112.doi: 10.15960/j.cnki.issn.1007-6093.2020.04.009

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Scheduling with tree-hierarchical processing set restrictions

ZHANG Yuzhong1,*, LI Shuguang2   

  1. 1. School of Operations Research, Qufu Normal University, Rizhao 276826, Shandong, China;
    2. College of Computer Science and Technology, Shandong Technology and Business University, Yantai 264005, Shandong, China
  • Received:2018-09-15 Published:2020-11-18

Abstract: The problem of scheduling with release times, delivery times and treehierarchical processing set restrictions is considered. Each job cannot begin processing before its release time, and its delivery begins immediately after processing has been completed. The machines form a tree hierarchical structure:any job requesting a certain machine may be assigned to any of its ancestors in the tree, and the set of these machines is the job's processing set. The objective is to minimize the maximum delivery completion time, i.e., the time by which all jobs are delivered. A polynomial time approximation scheme (PTAS) is presented when the jobs have both unequal release times and unequal delivery times.

Key words: scheduling, parallel machines, tree-hierarchical processing set restrictions, delivery time, polynomial time approximation scheme

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