TY - JOUR

T1 - Improved approximation algorithms for constrained fault-tolerant resource allocation

AU - Liao, Kewen

AU - Shen, Hong

AU - Guo, Longkun

N1 - Publisher Copyright:
© 2015 Elsevier B.V.

PY - 2015/7/26

Y1 - 2015/7/26

N2 - 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.

AB - 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.

KW - Approximation algorithms

KW - LP-rounding

KW - Primal-dual

KW - Reduction

KW - Resource allocation

KW - Time complexity

UR - http://www.scopus.com/inward/record.url?scp=84944732001&partnerID=8YFLogxK

U2 - 10.1016/j.tcs.2015.02.029

DO - 10.1016/j.tcs.2015.02.029

M3 - Article

AN - SCOPUS:84944732001

SN - 0304-3975

VL - 590

SP - 118

EP - 128

JO - Theoretical Computer Science

JF - Theoretical Computer Science

ER -