Improved approximation algorithms for constrained fault-tolerant resource allocation

Kewen Liao, Hong Shen, Longkun Guo

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


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) [1] and the classical Fault-Tolerant Facility Location (FTFL) [2] 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 [3]. 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.

Original languageEnglish
Pages (from-to)118-128
Number of pages11
JournalTheoretical Computer Science
Publication statusPublished - 26 Jul 2015
Externally publishedYes


  • Approximation algorithms
  • LP-rounding
  • Primal-dual
  • Reduction
  • Resource allocation
  • Time complexity


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