Browsing Combinatorics and Optimization by Subject "approximation algorithms"
Now showing items 1-12 of 12
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Algorithm Design for Ordinal Settings
(University of Waterloo, 2022-08-29)Social choice theory is concerned with aggregating the preferences of agents into a single outcome. While it is natural to assume that agents have cardinal utilities, in many contexts, we can only assume access to the ... -
Approximation Algorithms for Distributionally Robust Stochastic Optimization
(University of Waterloo, 2019-05-15)Two-stage stochastic optimization is a widely used framework for modeling uncertainty, where we have a probability distribution over possible realizations of the data, called scenarios, and decisions are taken in two stages: ... -
Approximation Algorithms for Graph Protection Problems
(University of Waterloo, 2015-05-22)We study a budgeted cut problem known as Graph Protection, where the goal is to remove edges of a given graph in order to protect valuable nodes from stochastic, infectious threats. This problem was recently proposed ... -
Building Networks in the Face of Uncertainty
(University of Waterloo, 2011-08-26)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 ... -
Capacitated Network Design on Outerplanar Graphs
(University of Waterloo, 2020-09-03)Network design problems model the efficient allocation of resources like routers, optical fibres, roads, canals etc. to effectively construct and operate critical infrastructures. In this thesis, we consider the capacitated ... -
Iterative Rounding Approximation Algorithms in Network Design
(University of Waterloo, 2010-05-21)Iterative rounding has been an increasingly popular approach to solving network design optimization problems ever since Jain introduced the concept in his revolutionary 2-approximation for the Survivable Network Design ... -
LP-based Approximation Algorithms for the Capacitated Facility Location Problem
(University of Waterloo, 2012-05-18)The capacitated facility location problem is a well known problem in combinatorial optimization and operations research. In it, we are given a set of clients and a set of possible facility locations. Each client has a ... -
On the Integrality Gap of Directed Steiner Tree Problem
(University of Waterloo, 2014-05-27)In the Directed Steiner Tree problem, we are given a directed graph G = (V,E) with edge costs, a root vertex r ∈ V, and a terminal set X ⊆ V . The goal is to find the cheapest subset of edges that contains an r-t path for ... -
Postman Problems on Mixed Graphs
(University of Waterloo, 2003)The <i>mixed postman problem</i> consists of finding a minimum cost tour of a mixed graph <i>M</i> = (<i>V</i>,<i>E</i>,<i>A</i>) traversing all its edges and arcs at least once. We prove that two well-known linear ... -
Stochastic Minimum Norm Combinatorial Optimization
(University of Waterloo, 2022-07-28)Motivated by growing interest in optimization under uncertainty, we undertake a systematic study of designing approximation algorithms for a wide class of 1-stage stochastic-optimization problems with norm-based objective ... -
Transversal Problems In Sparse Graphs
(University of Waterloo, 2022-09-20)Graph transversals are a classical branch of graph algorithms. In such a problem, one seeks a minimum-weight subset of nodes in a node-weighted graph $G$ which intersects all copies of subgraphs~$F$ from a fixed family ... -
The Traveling Tournament Problem
(University of Waterloo, 2022-08-17)In this thesis we study the Traveling Tournament problem (TTP) which asks to generate a feasible schedule for a sports league such that the total travel distance incurred by all teams throughout the season is minimized. ...