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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Incorporating the Centers for Disease Control and Prevention into Vaccine Pricing Models

Sinclair, Dina 01 January 2017 (has links)
The American vaccine pricing market has many actors, making it a complex system to model. Because of this, previous papers have chosen to model only vaccine manufacturers while leaving out the government. However, the government is also an important actor in the market, since it buys over half of vaccines produced. In this work, we aim to introduce the government into vaccine pricing models to better recommend pricing strategies to the Centers for Disease Control and Prevention.
52

The Cost and Benefit of Bulk Energy Storage in the Arizona Power Transmission System

January 2013 (has links)
abstract: This thesis addresses the issue of making an economic case for energy storage in power systems. Bulk energy storage has often been suggested for large scale electric power systems in order to levelize load; store energy when it is inexpensive and discharge energy when it is expensive; potentially defer transmission and generation expansion; and provide for generation reserve margins. As renewable energy resource penetration increases, the uncertainty and variability of wind and solar may be alleviated by bulk energy storage technologies. The quadratic programming function in MATLAB is used to simulate an economic dispatch that includes energy storage. A program is created that utilizes quadratic programming to analyze various cases using a 2010 summer peak load from the Arizona transmission system, part of the Western Electricity Coordinating Council (WECC). The MATLAB program is used first to test the Arizona test bed with a low level of energy storage to study how the storage power limit effects several optimization out-puts such as the system wide operating costs. Very high levels of energy storage are then added to see how high level energy storage affects peak shaving, load factor, and other system applications. Finally, various constraint relaxations are made to analyze why the applications tested eventually approach a constant value. This research illustrates the use of energy storage which helps minimize the system wide generator operating cost by "shaving" energy off of the peak demand. / Dissertation/Thesis / M.S. Electrical Engineering 2013
53

kernlab - An S4 Package for Kernel Methods in R

Karatzoglou, Alexandros, Smola, Alex, Hornik, Kurt, Zeileis, Achim 11 1900 (has links) (PDF)
kernlab is an extensible package for kernel-based machine learning methods in R. It takes advantage of R's new S4 object model and provides a framework for creating and using kernel-based algorithms. The package contains dot product primitives (kernels), implementations of support vector machines and the relevance vector machine, Gaussian processes, a ranking algorithm, kernel PCA, kernel CCA, and a spectral clustering algorithm. Moreover it provides a general purpose quadratic programming solver, and an incomplete Cholesky decomposition method.
54

Active-set prediction for interior point methods

Yan, Yiming January 2015 (has links)
This research studies how to efficiently predict optimal active constraints of an inequality constrained optimization problem, in the context of Interior Point Methods (IPMs). We propose a framework based on shifting/perturbing the inequality constraints of the problem. Despite being a class of powerful tools for solving Linear Programming (LP) problems, IPMs are well-known to encounter difficulties with active-set prediction due essentially to their construction. When applied to an inequality constrained optimization problem, IPMs generate iterates that belong to the interior of the set determined by the constraints, thus avoiding/ignoring the combinatorial aspect of the solution. This comes at the cost of difficulty in predicting the optimal active constraints that would enable termination, as well as increasing ill-conditioning of the solution process. We show that, existing techniques for active-set prediction, however, suffer from difficulties in making an accurate prediction at the early stage of the iterative process of IPMs; when these techniques are ready to yield an accurate prediction towards the end of a run, as the iterates approach the solution set, the IPMs have to solve increasingly ill-conditioned and hence difficult, subproblems. To address this challenging question, we propose the use of controlled perturbations. Namely, in the context of LP problems, we consider perturbing the inequality constraints (by a small amount) so as to enlarge the feasible set. We show that if the perturbations are chosen judiciously, the solution of the original problem lies on or close to the central path of the perturbed problem. We solve the resulting perturbed problem(s) using a path-following IPM while predicting on the way the active set of the original LP problem; we find that our approach is able to accurately predict the optimal active set of the original problem before the duality gap for the perturbed problem gets too small. Furthermore, depending on problem conditioning, this prediction can happen sooner than predicting the active set for the perturbed problem or for the original one if no perturbations are used. Proof-of-concept algorithms are presented and encouraging preliminary numerical experience is also reported when comparing activity prediction for the perturbed and unperturbed problem formulations. We also extend the idea of using controlled perturbations to enhance the capabilities of optimal active-set prediction for IPMs for convex Quadratic Programming (QP) problems. QP problems share many properties of LP, and based on these properties, some results require more care; furthermore, encouraging preliminary numerical experience is also presented for the QP case.
55

Frequentist Model Averaging For Functional Logistic Regression Model

Jun, Shi January 2018 (has links)
Frequentist model averaging as a newly emerging approach provides us a way to overcome the uncertainty caused by traditional model selection in estimation. It acknowledges the contribution of multiple models, instead of making inference and prediction purely based on one single model. Functional logistic regression is also a burgeoning method in studying the relationship between functional covariates and a binary response. In this paper, the frequentist model averaging approach is applied to the functional logistic regression model. A simulation study is implemented to compare its performance with model selection. The analysis shows that when conditional probability is taken as the focus parameter, model averaging is superior to model selection based on BIC. When the focus parameter is the intercept and slopes, model selection performs better.
56

Supervisory Control Optimization with Sequential Quadratic Programming for Parallel Hybrid Vehicle with Synchronous Power Sources

January 2017 (has links)
abstract: The thesis covers the development and modeling of the supervisory hybrid controller using two different methods to achieve real-world optimization and power split of a parallel hybrid vehicle with a fixed shaft connecting the Internal Combustion Engine (ICE) and Electric Motor (EM). The first strategy uses a rule based controller to determine modes the vehicle should operate in. This approach is well suited for real-world applications. The second approach uses Sequential Quadratic Programming (SQP) approach in conjunction with an Equivalent Consumption Minimization Strategy (ECMS) strategy to keep the vehicle in the most efficient operating regions. This latter method is able to operate the vehicle in various drive cycles while maintaining the SOC with-in allowed charge sustaining (CS) limits. Further, the overall efficiency of the vehicle for all drive cycles is increased. The limitation here is the that process is computationally expensive; however, with advent of the low cost high performance hardware this method can be used for the hybrid vehicle control. / Dissertation/Thesis / Masters Thesis Engineering 2017
57

Programação quadratica sequencial e condições de qualificação / Sequential quadratic programming and constraint qualification

Nunes, Fernanda Téles 03 September 2009 (has links)
Orientador: Maria Aparecida Diniz Ehrhardt / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-13T08:54:50Z (GMT). No. of bitstreams: 1 Nunes_FernandaTeles_M.pdf: 2400651 bytes, checksum: 206dfad35642a33d2de362510094e78d (MD5) Previous issue date: 2009 / Resumo: Abordando problemas de minimização de funções com restrições nos deparamos com as condições de otimalidade e, ainda, com condições de qualificação das res­trições. Nosso interesse é o estudo detalhado de várias condições de qualificação, com destaque para a condição de dependência linear positiva constante, e sua influência na convergência de algoritmos de Programação Quadrática Sequencial. A relevância deste estudo está no fato de que resultados de convergência que têm, em suas hipóteses, condições de qualificação fracas são mais fortes que aqueles baseados em condições de qualificação fortes. Experimentos numéricos serão realizados tanto para investigar a eficiência destes métodos na resolução de problemas com diferentes condições de qualificação, quanto para comparar dois diferentes tipos de busca, monótona e não-monótona. Tentamos confirmar a hipótese de que algoritmos baseados em uma busca não-monótona atuam contra o Efeito: Maratos, de comum ocorrência na resolução de problemas de minimização através de métodos de Programação Quadrática Sequencial. / Abstract: In the context of constrained optimization problems, we face the optimality conditions and also constraint qualification. Our aim is to study with details several constraint qualification, highlighting the constant positive linear dependence condition, and its influence in Sequential Quadratic Programming algorithms convergence. The relevance of this study is in the fact that convergence results having as hypothesis weak constraints qualification are stronger than those based on stronger constraints qualification. Numerical experiments will be done with the purpose of investigating the efficiency of these methods to solve problems with different constraints qualification and to compare two diferent kinds of line search, monotone and nonmonotone. We want to confirm the hypothesis that algorithms based on a nonmonotone line search act against the Maratos Effect, very common while solving minimization problems through Sequential Quadratic Programming methods. / Mestrado / Mestre em Matemática Aplicada
58

Condições de otimalidade em programação multiobjetivo fracional quadrático / Multiobjective quadratic fractional programming problems

Oliveira, Washington Alves de, 1977- 18 August 2018 (has links)
Orientador: Antonio Carlos Moretti, Margarida Pinheiro Mello / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica / Made available in DSpace on 2018-08-18T11:43:39Z (GMT). No. of bitstreams: 1 Oliveira_WashingtonAlvesde_D.pdf: 1534705 bytes, checksum: 351c92a12c85da49389a18880da92ee7 (MD5) Previous issue date: 2011 / Resumo: Existem na literatura diversos conceitos e definições que caracterizam e dão condições de otimalidade para as soluções de um problema de programação multiobjetivo. A mais importante é a condição necessária de primeira ordem, que generaliza a condição clássica do tipo Karush-Kuhn-Tucker em otimização não linear. Esta condição garante a existência de uma vizinhança arbitrária onde uma solução ótima está contida. No entanto, para se obter condições suficientes de otimalidade, tanto local como global, é necessário impor hipóteses adicionais sobre as funções objetivo e o conjunto de restrições, como convexidade ou as suas generalizações. Em determinados problemas tais hipóteses podem ser muito restritivas. Neste trabalho, introduzimos um conceito alternativo para identificar a vizinhança de uma solução ótima local em problemas de programação multiobjetivo. Em uma primeira etapa, usando este conceito, obtemos condições necessárias e suficientes de otimalidade para as soluções de um problema particular, onde cada função objetivo é constituída de um quociente de funções quadráticas e o conjunto de restrições é formado por desigualdades lineares. Então, mostramos como calcular o maior raio da região esférica centrada em uma solução ótima local na qual esta solução é ótima. Nesse processo, podemos concluir que esta solução também é globalmente ótima. Em uma segunda etapa, usando o gradiente e a Hessiana de cada função quadrática, caracterizamos as soluções ótimas locais. Em uma terceira etapa, obtemos condições suficientes de otimalidade global impondo algumas hipóteses adicionais, porém essas hipóteses não caracterizam nenhum tipo de convexidade generalizada sobre as funções objetivo. Finalizamos com alguns resultados de dualidade. Este problema particular, envolvendo otimização fracional, surge frequentemente em aplicações nos processos de tomada de decisão em Ciência da Gestão, por exemplo, quando se deseja otimizar razões como desempenho/custo, lucro/investimento, custo/tempo, etc. Por isso, também propomos ao longo do texto vários métodos computacionais derivados dos nossos resultados que podem ser usados na obtenção de soluções para esses tipos de aplicações / Abstract: In the literature there are several concepts and definitions that characterize and give optimality conditions for solutions of a multiobjective programming problem. The most important is the necessary first-order optimality condition that generalizes the Karush-Kuhn-Tucker conditions. This condition ensures the existence of an arbitrary neighborhood that contains an optimal solution. However, in order to obtain optimality sufficient conditions, both local and global, it is necessary to impose additional assumptions on the objective functions and on the feasible set such as convexity and its generalizations. Sometimes, in some problems, such assumptions are too restrictive. In this work, we introduce an alternative concept to identify the local optimal solution neighborhood in multiobjective programming problems. In a first step, using this concept, we obtain necessary and sufficient optimality conditions for the solutions of a particular problem, where each objective function consists of a ratio quadratic functions and the feasible set is defined by linear inequalities. Then we show how to calculate the largest radius of the spherical region centered on a local optimal solution in which the local solution is optimal. In this process we may conclude that the solution is also globally optimal. In a second step, using the gradient and the Hessian of each quadratic function, we characterize the local optimal solutions. In a third step, we obtain global optimality sufficient conditions by imposing some additional assumptions but these assumptions do not characterize any kind of generalized convexity on the objective functions. We conclude this work with some results of the duality. This particular problem, involving fractional optimization, arises frequently in the decision making of the management science applications, for example, if you want to otimize the performance/cost ratio, or profit/investment, or cost/time, etc.. Therefore, we also propose throughout the text various computational methods derived from our results. These methods can be used to obtain solutions to these types of applications / Doutorado / Matematica Aplicada / Doutor em Matemática Aplicada
59

Otimização de canteiros : quadriláteros de perímetro constante e área máxima / Optimization of grounds : quadrilaterals of constant perimeter and maximum area

Souza, Marília Franceschinelli de, 1984- 25 August 2018 (has links)
Orientador: Sandra Augusta Santos / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação Científica / Made available in DSpace on 2018-08-25T19:53:49Z (GMT). No. of bitstreams: 1 Souza_MariliaFranceschinellide_M.pdf: 3298789 bytes, checksum: cd2737cf2f9747a3856c42aee3ac5d83 (MD5) Previous issue date: 2014 / Resumo: O currículo de Matemática do Ensino Médio está atualmente muito denso e quase não permite ao professor explorar outros trabalhos que fujam das aulas expositivas, nas quais o papel do aluno é o de apenas escutar, anotar e reproduzir. Esse esquema antiquado desperta pouco interesse dos alunos pelas disciplinas, especialmente pela Matemática, tida por muitos como a vilã, bastante difícil de ser compreendida. Neste trabalho apresentamos uma proposta de projeto para ser trabalhado no Ensino Médio. O problema de otimização da área de quadriláteros de perímetro constante é abordado, utilizando essencialmente o conteúdo do Ensino Básico. O ponto de partida é um problema simples, presente na maioria dos livros-texto. A análise é ampliada gradativamente por situações mais próximas da realidade, oferecendo ao aluno a oportunidade de utilizar diversos conceitos estudados em uma aplicação da Matemática. Os problemas são abordados tanto de forma algébrica quanto geométrica, oferecendo elementos para que o aluno processe informações, anteveja possibilidades, analise o caso geral, exemplifique situações específicas e de fato possa compreender os problemas e interpretar as soluções obtidas / Abstract: The mathematics curriculum of the Brazilian High School is currently very dense. As a result, it is hard to explore alternative ways of teaching that allow the students to effectively participate in lessons, instead of just listening to the teacher and taking notes. The old fashioned expositive method, in general, does not encourage the interest of the students, especially in Mathematics, considered as a villain by many, because of it is intrinsic difficult. In this work it is presented the proposal of a project for the High School level. The problem of maximizing the area of quadrilaterals with constant perimeter is approached, using essentially the content of Basic Education. The starting point is a simple problem, present in most textbooks. The analysis is extended for situations closer to reality, offering students the opportunity to use many concepts already studied, in an application of mathematics. The problems are treated algebraically and geometrically, providing elements for the student to process information, anticipates possibilities, consider the general case, exemplify specific situations, so that they might indeed understand the problems and interpret the obtained solutions / Mestrado / Matemática em Rede Nacional / Mestra em Matemática em Rede Nacional
60

ROI: An extensible R Optimization Infrastructure

Theußl, Stefan, Schwendinger, Florian, Hornik, Kurt 01 1900 (has links) (PDF)
Optimization plays an important role in many methods routinely used in statistics, machine learning and data science. Often, implementations of these methods rely on highly specialized optimization algorithms, designed to be only applicable within a specific application. However, in many instances recent advances, in particular in the field of convex optimization, make it possible to conveniently and straightforwardly use modern solvers instead with the advantage of enabling broader usage scenarios and thus promoting reusability. This paper introduces the R Optimization Infrastructure which provides an extensible infrastructure to model linear, quadratic, conic and general nonlinear optimization problems in a consistent way. Furthermore, the infrastructure administers many different solvers, reformulations, problem collections and functions to read and write optimization problems in various formats. / Series: Research Report Series / Department of Statistics and Mathematics

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