dc.contributor.author | Gupta, Shubham | |
dc.date.accessioned | 2011-08-26 14:52:48 (GMT) | |
dc.date.available | 2011-08-26 14:52:48 (GMT) | |
dc.date.issued | 2011-08-26T14:52:48Z | |
dc.date.submitted | 2011 | |
dc.identifier.uri | http://hdl.handle.net/10012/6140 | |
dc.description.abstract | The subject of this thesis is to study approximation algorithms for some network design problems in face of uncertainty. We consider two widely studied models of handling uncertainties - Robust Optimization and Stochastic Optimization. We study a robust version of the well studied Uncapacitated Facility Location Problem (UFLP). In this version, once the set of facilities to be opened is decided, an adversary may close at most β facilities. The clients must then be assigned to the remaining open facilities. The performance of a solution is measured by the worst possible set of facilities that the adversary may close. We introduce a novel LP for the problem, and provide an LP rounding algorithm when all facilities have same opening costs. We also study the 2-stage Stochastic version of the Steiner Tree Problem. In this version, the set of terminals to be covered is not known in advance. Instead, a probability distribution over the possible sets of terminals is known. One is allowed to build a partial solution in the first stage a low cost, and when the exact scenario to be covered becomes known in the second stage, one is allowed to extend the solution by building a recourse network, albeit at higher cost. The aim is to construct a solution of low cost in expectation. We provide an LP rounding algorithm for this problem that beats the current best known LP rounding based approximation algorithm. | en |
dc.language.iso | en | en |
dc.publisher | University of Waterloo | en |
dc.subject | robust optimization | en |
dc.subject | stochastic optimization | en |
dc.subject | network design | en |
dc.subject | facility location | en |
dc.subject | steiner tree | en |
dc.subject | steiner forest | en |
dc.subject | approximation algorithms | en |
dc.title | Building Networks in the Face of Uncertainty | en |
dc.type | Master Thesis | en |
dc.pending | false | en |
dc.subject.program | Combinatorics and Optimization | en |
uws-etd.degree.department | Combinatorics and Optimization | en |
uws-etd.degree | Master of Mathematics | en |
uws.typeOfResource | Text | en |
uws.peerReviewStatus | Unreviewed | en |
uws.scholarLevel | Graduate | en |