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.
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Showing 1 to 20 of 50 for “"Local optima"”.
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Local Optima in K-Means Clustering
"The study of the properties of local optimality in K-means clustering is pursued. In doing so, it is shown that several of the commercial software packages prove to be inadequate in their treatment of the K-means algorithm, resulting in the proposal of an alternative method based on several …
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Identification and investigation of local optima in aerospace structural design
… thesis reports on research into the causes of local optima when optimization algorithms are applied to aerospace structural design. A thorough understanding of local optima will enable the engineers to select the algorithm for optimization or to guide the optimization to ensure either global …
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Modifying landscapes with penalties in iterative improvement for solving distributed constraint satisfaction problems.
… But, it also has a propensity to converge to local optima in the process. Previous work on iterative improvement search (in centralised and distributed forms) has considered a variety of techniques for dealing with the problem of convergence on local optima. Prominent amongst these include …
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Generalized partition crossover for the traveling salesman problem
… operators for the TSP in that recombining two local optima produces new local optima with a high probability. Thus the operator can 'tunnel' between local optima without the need for intermediary solutions. The operator is respectful, meaning that any edges common between the two parent …
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A Combined Motif Discovery Method
… embedded into classic Gibbs sampling to avoid local optima. This method was applied to the 18 pieces DNA sequences containing CRP binding sites validated by Stormo and the results were compared with Bioprospector. Based on the results, the new scoring schema can get over the defect that the …
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A Local Search Algorithm Approach to Analyzing the Complexity of Discrete Optimization Problems
… neighborhood functions have arbitrarily poor local optima.
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Informed selection and use of training examples for knowledge refinement.
… repairs but run the risk of getting caught in local optima. A novel contribution of this thesis is solving the local optima problem by converting the hill-climbing search into a best-first search that can backtrack to previous refinement states. The thesis explores how different backtracking …
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Artificial evolution with Binary Decision Diagrams: a study in evolvability in neutral spaces
… exploration, completely alleviating local optima. Population diversity, in conjunction with neutrality, is shown to facilitate the evolution of evolvability. The search is robust, scalable, and insensitive to the absence of initial diversity. The thesis concludes that gradual …
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Combining search strategies for distributed constraint satisfaction.
… terms of related subproblems, called a complex local problem (CLP), which are dispersed over a number of locations, each with its own constraints on the values their variables can take. An agent knows the variables in its CLP plus the variables (and their current value) which are directly …
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Rules of engagement: competitive coevolutionary dynamics in computational systems
… mutations can push a population towards local optima that are difficult to escape. Coevolution offers a solution. By allowing the fitness of each evolving individual to vary (through competition) with other reciprocally evolving individuals, coevolution removes the requirement of a …
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Geometrically Nonlinear Aeroelastic Scaling
… linear applications: new sources of local optima are identified, and modal mass is identified as a scaling parameter. Optimization procedures for addressing the multiple optima and modal mass matching are developed and demonstrated. Where justified, limitations of commercial software …
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Algorithms for matrix completion
… ratings. However, the corresponding problem has local optima. In this thesis, we study two approaches to remedy this issue: reference vector method and trace norm regularization. The reference vector method explicitly constructs user and item features based on similarities to reference sets of …
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Surpassing Local Optimality in Geometry Processing
… with Newton’s method to initialization dependent local optima. In this thesis, we examine whether problem specific knowledge can be leveraged to employ more advanced optimization techniques and obtain better results. We specifically explore the use of convex relaxation, variable augmentation and …
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Efficient orchestration of data centers via comprehensive and application-aware trade-off exploration
… control functions (NCFs) while minimizing suboptimal network states that can result from competing NCF proposals, is a challenging open problem. In this work, we formulate SDN orchestration as a multiobjective optimization problem, present an evolutionary algorithm designed to explore the NCF …
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A multiobjective, multidisciplinary design optimization methodology for the conceptual design of distributed satellite systems
… consistency due to its ability to escape local optima within a nonconvex trade space. Accordingly, this SA algorithm forms the core single objective MDO algorithm in the methodology. The DSS conceptual design problem scope is then broadened by expanding from single objective to …
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Blending Methods for Composite Laminate Optimization
… panel optimization subproblems, with specified local loads, resulting in manufacturing incompatibilities between adjacent panel designs. Using genetic algorithms to optimize local panel stacking sequences allows panel populations of stacking sequences to evolve in parallel and send migrants to …
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Optimization Frameworks for Discrete Composite Laminate Stacking Sequences
… panel optimization subproblems, with specified local loads, resulting in manufacturing incompatibilities between adjacent panel designs. Using genetic algorithms to optimize local panel stacking sequences allows panel populations of stacking sequences to evolve in parallel and send migrants to …
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Improving Protein Docking Using Efficient Sustainable Evolutionary Algorithm
… of these algorithms is still limited by the local optima issue in simulated annealing or the premature convergence issue existing in traditional evolutionary algorithm models. And due to the stochastic nature of the search algorithms, usually users need to do multiple runs to get reasonable …
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Soft computing y aprendizaje automático para la segmentación de imágenes con modelos deformables
… methods can lead to inaccuracies, that is, local optima in the sense of optimization. Besides, it is possible that DMs in general present problems related to the the way they are adjusted. In fact, since the global minimum of the energy function should correspond to the ideal segmentation …
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An effective algorithm for multiway hypergraph partitioning
… on both cell gains and net gains. To escape from local optima and to search broader solution space, we propose a new perturbation mechanism. These two strategies significantly enhance the solution quality produced by our algorithm. Based on our experimental justification, we also smoothly decrease …
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