Title
Covering points by unit disks of fixed location
Abstract
Given a set P of points in the plane, and a set D of unit disks of fixed location, the discrete unit disk cover problem is to find a minimum-cardinality subset D′ ⊆ D that covers all points of P. This problem is a geometric version of the general set cover problem, where the sets are defined by a collection of unit disks. It is still NP-hard, but while the general set cover problem is not approximable within c log |P|, for some constant c, the discrete unit disk cover problem was shown to admit a constant-factor approximation. Due to its many important applications, e.g., in wireless network design, much effort has been invested in trying to reduce the constant of approximation of the discrete unit disk cover problem. In this paper we significantly improve the best known constant from 72 to 38, using a novel approach. Our solution is based on a 4-approximation that we devise for the subproblem where the points of P are located below a line l and contained in the subset of disks of D centered above l. This problem is of independent interest.
Year
DOI
Venue
2007
10.1007/978-3-540-77120-3_56
ISAAC
Keywords
Field
DocType
constant c,unit disk,line l,c log,minimum-cardinality subset,set p,general set cover problem,constant-factor approximation,discrete unit disk cover,fixed location,set d,wireless network,set covering problem
Discrete mathematics,Set cover problem,Wireless network,Combinatorics,Computer science,Smallest-circle problem,Vertex cover,Unit disk
Conference
Volume
ISSN
ISBN
4835
0302-9743
3-540-77118-2
Citations 
PageRank 
References 
40
1.52
8
Authors
3
Name
Order
Citations
PageRank
Paz Carmi132143.14
Matthew J. Katz213012.41
Nissan Lev-Tov31377.91