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41st Annual Symposium on Foundations of Computer Science
The online median problem
Redondo Beach, California
November 12November 14
ISBN: 0769508502
ASCII Text  x  
R.R. Mettu, C.G. Plaxton, "The online median problem," 2013 IEEE 54th Annual Symposium on Foundations of Computer Science, pp. 339, 41st Annual Symposium on Foundations of Computer Science, 2000.  
BibTex  x  
@article{ 10.1109/SFCS.2000.892122, author = {R.R. Mettu and C.G. Plaxton}, title = {The online median problem}, journal ={2013 IEEE 54th Annual Symposium on Foundations of Computer Science}, volume = {0}, year = {2000}, issn = {02725428}, pages = {339}, doi = {http://doi.ieeecomputersociety.org/10.1109/SFCS.2000.892122}, publisher = {IEEE Computer Society}, address = {Los Alamitos, CA, USA}, }  
RefWorks Procite/RefMan/Endnote  x  
TY  CONF JO  2013 IEEE 54th Annual Symposium on Foundations of Computer Science TI  The online median problem SN  02725428 SP EP A1  R.R. Mettu, A1  C.G. Plaxton, PY  2000 KW  facility location; heuristic programming; approximation theory; online median problem; kmedian problem; competitive ratio; worstcase ratio; lineartime constantcompetitive algorithm; lineartime constantfactor approximation algorithm; primaldualbased facility location algorithm VL  0 JA  2013 IEEE 54th Annual Symposium on Foundations of Computer Science ER   
We introduce a natural variant of the (metric uncapacitated) kmedian problem that we call the online median problem. Whereas the kmedian problem involves optimizing the simultaneous placement of k facilities, the online median problem imposes the following additional constraints: the facilities are placed one at a time; a facility cannot be moved once it is placed, and the total number of facilities to be placed, k, is not known in advance. The objective of an online median algorithm is to minimize the competitive ratio, that is, the worstcase ratio of the cost of an online placement to that of an optimal offline placement. Our main result is a lineartime constantcompetitive algorithm for the online median problem. In addition, we present a related, though substantially simpler lineartime constantfactor approximation algorithm for the (metric uncapacitated) facility location problem. The latter algorithm is similar in spirit to the recent primaldualbased facility location algorithm of Jain and Vazirani, but our approach is more elementary and yields an improved running time.
Index Terms:
facility location; heuristic programming; approximation theory; online median problem; kmedian problem; competitive ratio; worstcase ratio; lineartime constantcompetitive algorithm; lineartime constantfactor approximation algorithm; primaldualbased facility location algorithm
Citation:
R.R. Mettu, C.G. Plaxton, "The online median problem," focs, pp.339, 41st Annual Symposium on Foundations of Computer Science, 2000
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