Approximation algorithms for the single allocation problem in hub-and-spoke networks and related metric labeling problems

This paper deals with a single allocation problem in hub-and-spoke networks. We present a simple deterministic 3-approximation algorithm and randomized 2-approximation algorithm based on a linear relaxation problem and a randomized rounding procedure. We handle the case where the number of hubs is t...

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Bibliographic Details
Published in:Discrete Applied Mathematics Vol. 157; no. 9; pp. 2078 - 2088
Main Authors: Iwasa, Masaru, Saito, Hiroo, Matsui, Tomomi
Format: Journal Article Conference Proceeding
Language:English
Published: Kidlington Elsevier B.V 06.05.2009
Elsevier
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ISSN:0166-218X, 1872-6771
Online Access:Get full text
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Summary:This paper deals with a single allocation problem in hub-and-spoke networks. We present a simple deterministic 3-approximation algorithm and randomized 2-approximation algorithm based on a linear relaxation problem and a randomized rounding procedure. We handle the case where the number of hubs is three, which is known to be NP-hard, and present a (5/4)-approximation algorithm. The single allocation problem includes a special class of the metric labeling problem, defined by introducing an assumption that both objects and labels are embedded in a common metric space. Under this assumption, we can apply our algorithms to the metric labeling problem without losing theoretical approximation ratios. As a byproduct, we also obtain a (4/3)-approximation algorithm for an ordinary metric labeling problem with three labels.
ISSN:0166-218X
1872-6771
DOI:10.1016/j.dam.2008.11.016