Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 122 for “"Approximation algorithm"”.
-
A multiscale approximation algorithm for the cardinality constrained knapsack problem
I develop a multiscale approximation algorithm for the cardinality constrained knapsack problem. The algorithm consists of three steps: a rounding and reduction step where a hierarchical representation of the problem data ranging from coarse to fine is generated, a solution step where a coarse …
-
A Grid-Based Approximation Algorithm for the Minimum Weight Triangulation Problem
… be NP-Hard. We present a novel polynomial-time algorithm that computes a 16-approximation of the minimum weight triangulation---a constant that is significantly smaller than what has been previously known. To construct our candidate solution, our algorithm uses grids to partition edges into …
-
The Adaptive Cross Approximation Algorithm Applied to Electromagnetic Scattering by Bodies of Revolution
… of computational resources. The adaptive cross approximation (ACA) algorithm is a method which can be used to efficiently compute and store these matricies. This thesis will apply the ACA to a special class of problems known as scattering by bodies of revolution. A brief introduction to …
-
A pseudo-polynomial time O(log² n)-approximation algorithm for art gallery problems
… we give a pseudo-polynomial time O(log² n)-approximation algorithm for a variant of the art gallery problem the point-guard problem. The point-guard problem involves finding the minimum number of points and their positions so that guards located at these points cover the interior of the art …
-
W-SPSA : an Efficient Stochastic Approximation Algorithm for the off-line calibration of Dynamic Traffic Assignment models
… problem. Simultaneous Perturbation Stochastic Approximation (SPSA) has been reported in the literature to be the most suitable solution algorithm for this problem due to its highly efficient gradient estimation approach. However, it turns out that the performance of SPSA in terms of convergence …
-
Approximation algorithms for stochastic scheduling on unrelated machines
… presents the first nontrivial polynomial time approximation algorithms for an important class of machine scheduling problems. We study the family of preemptive minimum makespan scheduling problems where jobs have stochastic processing requirements and provide the first approximation algorithms …
-
Algorithms for Vertex-Weighted Matching in Graphs
… coarsen graphs in multi-level graph partitioning algorithms. In the first part of this thesis, we develop exact and approximation algorithms for vertex weighted matchings, an under-studied variant of the weighted matching problem. We propose three exact algorithms, three half approximation …
-
Approximation algorithms for low-distortion embeddings into low-dimensional spaces
We present several approximation algorithms for the problem of embedding metric spaces into a line, and into the two-dimensional plane. We give an O([square root] n)-approximation algorithm for the problem of finding a line embedding of a metric induced by a given unweighted graph, that minimizes …
-
Toward efficient online scheduling for large-scale distributed machine learning system
… question is how to design efficient scheduling algorithms to allocate workers and parameter servers across different machines to minimize the overall training time. Toward this end, in this paper, we develop an online scheduling algorithm that jointly optimizes resource allocation and locality …
-
Approximation algorithms for distributed and selfish agents
… own self interest. In this thesis, we develop approximation algorithms and decentralized mechanisms for various combinatorial optimization problems in such systems. First, we investigate the distributed caching and a general set of assignment problems. We develop an almost tight LP-based ... …
-
On approximating projection games
… great significance in the field of hardness of approximation since almost all NP-hardness of approximation results known today are derived from the NP-hardness of approximation of projection games. Hence, it is important to determine the exact approximation ratio at which projection games become …
-
Three essays on sequencing and routing problems
… of problems are sequencing problems. We study approximation algorithms and local search heuristics for these problems. First, we analyze the Vehicle Routing Problem (VRP) with and without split deliveries. In this problem, we have to route vehicles from the depot to deliver the demand to the …
-
Algorithmic and game-theoretic perspectives on scheduling
… problem, and give a combinatorial primal-dual 2-approximation algorithm.
-
Distributed construction of energy-efficient ad hoc wireless broadcast trees
… broadcast tree is NP-complete and develop an approximation algorithm, which computes sub-optimal solutions in polynomial time. We present a distributed algorithm that computes all N possible broadcast trees simultaneously with O(N2) message complexity. We compare our algorithm's performance to …
-
Learning structure in nested logit models
… and solve it using a variant of the linear outer approximation algorithm. We demonstrate that it is indeed possible to recover the nesting structure directly from the data by applying our method to synthetic and real datasets.
-
Computational metric embeddings
… present the following upper bounds. We give an approximation algorithm that, given a metric space that embeds into R1 with distortion c, computes an embedding with distortion c(1) [delta]3/4 (A denotes the ratio of the maximum over the minimum distance). For higher-dimensional spaces, we obtain …
-
Covering problem with minimum radius enclosing circle
… model and propose a quadratic programming-based approximation algorithm to solve it. Tested on various hypothetical and real scenarios, our model effectively reduces the facility setup cost and identifies the optimal communication hub location.
-
Finding Patterns, Short Cycles and Long Shortest Paths in Graphs
… finding useful structures in a graph using fast algorithms, or showing that no such fast algorithms exist using popular fine-grained hypotheses from the field of Fine-Grained Complexity. These structures can be any small fixed-sized pattern, or more specific bigger structures such as the longest …
-
Optimisation over the non-dominated set of a multi-objective optimisation problem
… over the non-dominated set. We present two new algorithms for the optimisation of a linear function over the non-dominated set of a multi-objective linear programme (MOLP). A primal method is developed based on a revised version of Benson’s outer approximation algorithm. A dual method derived …
-
High Multiplicity Strip Packing
… sizes and present an OPT + K - 1 polynomial-time approximation algorithm for it. This beats a previous algorithm with a worst case bound of OPT + K; the time complexity of that algorithm was not known and here we show that it runs in polynomial time.
Page 1 of 7