Improved approximation algorithms for constrained fault-tolerant resource allocation

  • Authors:

  • Kewen Liao;Hong Shen;Longkun Guo

  • Affiliations:

  • School of Computer Science, The University of Adelaide, Adelaide, Australia;School of Computer Science, The University of Adelaide, Adelaide, Australia,School of Computer and Information Technology, Sun Yat-sen University, Guangzhou, China;School of Computer and Information Technology, Sun Yat-sen University, Guangzhou, China

  • Venue:
  • FCT'13 Proceedings of the 19th international conference on Fundamentals of Computation Theory
  • Year:
  • 2013

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Abstract

In Constrained Fault-Tolerant Resource Allocation (FTRA) problem, we are given a set of sites containing facilities as resources and a set of clients accessing these resources. Each site i can open at most Ri facilities with opening cost fi. Each client j requires an allocation of rj open facilities and connecting j to any facility at site i incurs a connection cost cij. The goal is to minimize the total cost of this resource allocation scenario. FTRA generalizes the Unconstrained Fault-Tolerant Resource Allocation (FTRA∞) [10] and the classical Fault-Tolerant Facility Location (FTFL) [7] problems: for every site i, FTRA∞ does not have the constraint Ri, whereas FTFL sets Ri=1. These problems are said to be uniform if all rj's are the same, and general otherwise. For the general metric FTRA, we first give an LP-rounding algorithm achieving an approximation ratio of 4. Then we show the problem reduces to FTFL, implying the ratio of 1.7245 from [2]. For the uniform FTRA, we provide a 1.52-approximation primal-dual algorithm in O(n4) time, where n is the total number of sites and clients.