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Journal of Global Optimization

, Volume 49, Issue 2, pp 359–362 | Cite as

Comments on “Competitive analysis of a better on-line algorithm to minimize total completion time on a single-machine”

  • Jiping Tao
  • Zhijun Chao
  • Yugeng Xi
Article
  • 86 Downloads

Abstract

For the single machine scheduling problem of minimizing the total completion time, Montoya Torres (J Glob Opt 27:97–103, 2003) presented a semi-online algorithm under the assumption that release dates are known in advance, and showed that it was \({\sqrt{3}}\)-competitive. However, there are flaws in the proof, and the conclusion about the competitive ratio is not correct. In this note, we show that the semi-online algorithm cannot perform better than the best non-clairvoyant online algorithm with a competitive ratio of 2.

Keywords

Single-machine scheduling Total completion time Competitive analysis 

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References

  1. 1.
    Montoya Torres J.R.: Competitive analysis of a better on-line algorithm to minimize total completion time on a single-machine. J. Glob. Opt. 27(1), 97–103 (2003)CrossRefGoogle Scholar
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    Hoogeveen, J.A., Vestjens, A.P.A.: Optimal on-line algorithms for single-machine scheduling. In: Goos, G., Hartmanis, J., Leeuwen, J.V. (eds.) Integer Programming and Combinatorial Optimization, the 5th International IPCO Conference Vancouver, British Columbia, Canada, June 1996. Lecture Notes in Computer Science, vol. 1084, pp. 404–414. Springer, Berlin (1996)Google Scholar
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    Fiat A., Woeginger G.: Online Algorithms: The State of the Art. Springer, Berlin (1998)Google Scholar

Copyright information

© Springer Science+Business Media, LLC. 2010

Authors and Affiliations

  1. 1.Department of AutomationShanghai Jiao Tong UniversityShanghaiChina

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