Operations Research Transactions ›› 2019, Vol. 23 ›› Issue (1): 111-118.doi: 10.15960/j.cnki.issn.1007-6093.2019.01.013

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Online batch scheduling problem on uniform machines with agreeable processing times

PENG Nannan*, ZHANG Yuzhong, BAI Qingguo, WANG Chengfei   

  1. Institute of Operations Research, School of Management, Qufu Normal University, Rizhao 276826, Shandong, China
  • Received:2017-12-18 Online:2019-03-15 Published:2019-03-15

Abstract:

We study the online batch scheduling problem on two uniform machines, where the batch capacity is unbounded. When the arrival times and the processing times of jobs are agreeable, two scheduling models whose objectives are to minimize the makespan and flow-time are developed and they are expressed as Q2|ri < rjpipj, B=∞, on-line|Cmax and Q2|ri < rjpipj, B=∞, on-line|Fmax. Without loss of generality, the speeds of the two machines are assumed to be 1 and s,s ≥ 1. We propose an on-line algorithm and prove the competitive ratios of the algorithm are not more than s+α and 1+1/α, respectively, where α is the positive root of α2+-1=0. Moreover, for the former scheduling model, we prove that the competitive ratio of the algorithm is not more than 1.618, when s=1.

Key words: batch scheduling, online algorithm, uniform machine, competitive ratio, agreeable processing time

CLC Number: