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Off-Line Algorithms for Minimizing Total Flow Time in Broadcast Scheduling

  • Wun-Tat Chan
  • Francis Y. L. Chin
  • Yong Zhang
  • Hong Zhu
  • Hong Shen
  • Prudence W. H. Wong
Part of the Lecture Notes in Computer Science book series (LNCS, volume 3595)

Abstract

We study the off-line broadcast scheduling problem to minimize total (or average) flow time. Assume the server has k pages and the requests arrive at n distinct times, we give the first algorithm to find the optimal schedule for the server with a single channel, in O(k3(n+k)k − − 1) time. For m-channel case, i.e., the server can broadcast m different pages at a time where m < k, we find the optimal schedule in O(nk − − m) time when k and m are constants. In the single channel case, we also give a simple linear-time approximation algorithm to minimize average flow time, which achieves an additive (k–1)/2-approximation.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2005

Authors and Affiliations

  • Wun-Tat Chan
    • 1
  • Francis Y. L. Chin
    • 1
  • Yong Zhang
    • 1
  • Hong Zhu
    • 2
  • Hong Shen
    • 3
  • Prudence W. H. Wong
    • 4
  1. 1.Department of Computer ScienceUniversity of Hong KongHong Kong
  2. 2.Department of Computer Science and EngineeringFudan UniversityChina
  3. 3.Graduate School of Information ScienceJapan Advanced Institute of Science and TechnologyJapan
  4. 4.Department of Computer ScienceUniversity of LiverpoolUK

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