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When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.ISAAC.2017.49
URN: urn:nbn:de:0030-drops-82292
URL: http://drops.dagstuhl.de/opus/volltexte/2017/8229/
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Jahanjou, Hamidreza ; Kantor, Erez ; Rajaraman, Rajmohan

Improved Algorithms for Scheduling Unsplittable Flows on Paths

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LIPIcs-ISAAC-2017-49.pdf (0.9 MB)


Abstract

In this paper, we investigate offline and online algorithms for Round-UFPP, the problem of minimizing the number of rounds required to schedule a set of unsplittable flows of non-uniform sizes on a given path with non-uniform edge capacities. Round-UFPP is NP-hard and constant-factor approximation algorithms are known under the no bottleneck assumption (NBA), which stipulates that maximum size of a flow is at most the minimum edge capacity. We study Round-UFPP without the NBA, and present improved online and offline algorithms. We first study offline Round-UFPP for a restricted class of instances called alpha-small, where the size of each flow is at most alpha times the capacity of its bottleneck edge, and present an O(log(1/(1 - alpha)))-approximation algorithm. Our main result is an online O(log log cmax)-competitive algorithm for Round-UFPP for general instances, where cmax is the largest edge capacities, improving upon the previous best bound of O(log cmax) due to [16]. Our result leads to an offline O(min(log n, log m, log log cmax))- approximation algorithm and an online O(min(log m, log log cmax))-competitive algorithm for Round-UFPP, where n is the number of flows and m is the number of edges.

BibTeX - Entry

@InProceedings{jahanjou_et_al:LIPIcs:2017:8229,
  author =	{Hamidreza Jahanjou and Erez Kantor and Rajmohan Rajaraman},
  title =	{{Improved Algorithms for Scheduling Unsplittable Flows on Paths}},
  booktitle =	{28th International Symposium on Algorithms and Computation (ISAAC 2017)},
  pages =	{49:1--49:12},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-054-5},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{92},
  editor =	{Yoshio Okamoto and Takeshi Tokuyama},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{http://drops.dagstuhl.de/opus/volltexte/2017/8229},
  URN =		{urn:nbn:de:0030-drops-82292},
  doi =		{10.4230/LIPIcs.ISAAC.2017.49},
  annote =	{Keywords: Approximation algorithms, Online algorithms, Unsplittable flows, Interval coloring, Flow scheduling}
}

Keywords: Approximation algorithms, Online algorithms, Unsplittable flows, Interval coloring, Flow scheduling
Seminar: 28th International Symposium on Algorithms and Computation (ISAAC 2017)
Issue Date: 2017
Date of publication: 04.12.2017


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