Dissertations / Theses on the topic 'Weighted least squares'
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Wang, Zhen. "Semi-parametric Bayesian Models Extending Weighted Least Squares." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1236786934.
Full textWei, Fei. "Weighted least-squares finite element methods for PIV data assimilation." Thesis, Montana State University, 2011. http://etd.lib.montana.edu/etd/2011/wei/WeiF0811.pdf.
Full textRosopa, Patrick. "A COMPARISON OF ORDINARY LEAST SQUARES, WEIGHTED LEAST SQUARES, AND OTHER PROCEDURES WHEN TESTING FOR THE EQUALITY OF REGRESSION." Doctoral diss., University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2311.
Full textPh.D.
Department of Psychology
Sciences
Psychology
Fang, Xing [Verfasser]. "Weighted total least squares solutions for applications in geodesy / Xing Fang." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2011. http://d-nb.info/1015446590/34.
Full textViklands, Thomas. "Algorithms for the Weighted Orthogonal Procrustes Problem and other Least Squares Problems." Doctoral thesis, Umeå : Umeå universitet, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-730.
Full textCheng, Chao-heh. "Calculations for positioning with the Global Navigation Satellite System." Ohio : Ohio University, 1998. http://www.ohiolink.edu/etd/view.cgi?ohiou1176839268.
Full textKamunge, Daniel. "A non-linear weighted least squares gas turbine diagnostic approach and multi-fuel performance simulation." Thesis, Cranfield University, 2011. http://dspace.lib.cranfield.ac.uk/handle/1826/5612.
Full textShulga, Yelena A. "Model-based calibration of a non-invasive blood glucose monitor." Digital WPI, 2006. https://digitalcommons.wpi.edu/etd-theses/58.
Full textOxby, Paul W. "Multivariate weighted least squares as a preferable alternative to the determinant criterion for multiresponse parameter estimation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq22225.pdf.
Full textKim, Wonho. "An improved bus signal priority system for networks with nearside bus stops." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1460.
Full textZheng, Shimin, and A. K. Gupta. "A New Approach to Statistical Efficiency of Weighted Least Squares Fitting Algorithms for Reparameterization of Nonlinear Regression Models." Digital Commons @ East Tennessee State University, 2012. https://dc.etsu.edu/etsu-works/36.
Full textNusrat, Nazia. "Development of novel electrical power distribution system state estimation and meter placement algorithms suitable for parallel processing." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/10902.
Full textCan, Mutan Oya. "Comparison Of Regression Techniques Via Monte Carlo Simulation." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/3/12605175/index.pdf.
Full textFreeman, Laura J. "Statistical Methods for Reliability Data from Designed Experiments." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/37729.
Full textPh. D.
Portas, Lance O. "An unstructured numerical method for computational aeroacoustics." Thesis, Loughborough University, 2009. https://dspace.lboro.ac.uk/2134/16694.
Full textSporre, Göran. "On Some Properties of Interior Methods for Optimization." Doctoral thesis, KTH, Mathematics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3472.
Full textThis thesis consists of four independent papers concerningdifferent aspects of interior methods for optimization. Threeof the papers focus on theoretical aspects while the fourth oneconcerns some computational experiments.
The systems of equations solved within an interior methodapplied to a convex quadratic program can be viewed as weightedlinear least-squares problems. In the first paper, it is shownthat the sequence of solutions to such problems is uniformlybounded. Further, boundedness of the solution to weightedlinear least-squares problems for more general classes ofweight matrices than the one in the convex quadraticprogramming application are obtained as a byproduct.
In many linesearch interior methods for nonconvex nonlinearprogramming, the iterates can "falsely" converge to theboundary of the region defined by the inequality constraints insuch a way that the search directions do not converge to zero,but the step lengths do. In the sec ond paper, it is shown thatthe multiplier search directions then diverge. Furthermore, thedirection of divergence is characterized in terms of thegradients of the equality constraints along with theasymptotically active inequality constraints.
The third paper gives a modification of the analytic centerproblem for the set of optimal solutions in linear semidefiniteprogramming. Unlike the normal analytic center problem, thesolution of the modified problem is the limit point of thecentral path, without any strict complementarity assumption.For the strict complementarity case, the modified problem isshown to coincide with the normal analytic center problem,which is known to give a correct characterization of the limitpoint of the central path in that case.
The final paper describes of some computational experimentsconcerning possibilities of reusing previous information whensolving system of equations arising in interior methods forlinear programming.
Keywords:Interior method, primal-dual interior method,linear programming, quadratic programming, nonlinearprogramming, semidefinite programming, weighted least-squaresproblems, central path.
Mathematics Subject Classification (2000):Primary90C51, 90C22, 65F20, 90C26, 90C05; Secondary 65K05, 90C20,90C25, 90C30.
Nilsson, Max. "Performance Comparison of Localization Algorithms for UWB Measurements with Closely Spaced Anchors." Thesis, Luleå tekniska universitet, Rymdteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-70996.
Full textBoruvka, Audrey. "Data-driven estimation for Aalen's additive risk model." Thesis, Kingston, Ont. : [s.n.], 2007. http://hdl.handle.net/1974/489.
Full textLuo, Hao. "Some Aspects on Confirmatory Factor Analysis of Ordinal Variables and Generating Non-normal Data." Doctoral thesis, Uppsala universitet, Statistiska institutionen, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-149423.
Full textDavis, Brett Andrew, and Brett Davis@abs gov au. "Inference for Discrete Time Stochastic Processes using Aggregated Survey Data." The Australian National University. Faculty of Economics and Commerce, 2003. http://thesis.anu.edu.au./public/adt-ANU20040806.104137.
Full textWalczak, Katarzyna I. "Prototype decision support framework using geospatial technologies for analysing human health risk." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/103630/1/Katarzyna%20Izabella_Walczak_Thesis.pdf.
Full textKatsikatsou, Myrsini. "Composite Likelihood Estimation for Latent Variable Models with Ordinal and Continuous, or Ranking Variables." Doctoral thesis, Uppsala universitet, Statistiska institutionen, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-188342.
Full textFrazão, Rodrigo José Albuquerque. "MÉTODOS ALTERNATIVOS PARA ESTIMAÇÃO DE ESTADO EM SISTEMAS DE ENERGIA ELÉTRICA." Universidade Federal do Maranhão, 2012. http://tedebc.ufma.br:8080/jspui/handle/tede/475.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
The state estimation process applied to electric power systems aims to provide a trustworthy ―image‖, coherent and complete of the system operation, allowing an efficient monitoring. The state estimation is one of the most important functions of energy management systems. In this work, will be proposed alternative methods of state estimation for electric power systems in the levels of transmission, subtransmission and distribution. For transmission systems are proposed two hybrid methods considering the insertion of conventional measurements combined with phasor measurements based on phasor measurement unit (PMU). To estimate the state in subtransmission systems is proposed an alternative method which, in occurrence of failures in active and/or reactive meters in the substations, uses a load forecasting model based on criteria similar days and application of artificial neural networks. This process of load forecasting is used as a generator of pseudo measurements in state estimation problem, which takes place through the propagation of phasor measurements provided by a PMU placed in the boundary busbar. For the distribution system state estimation the proposed method uses the mathematical method of weighted least squares with equality constraints by modifying the set of measurements and the state variables. It is also proposed a methodology evaluation of the PMUs measurement channel availability for observability analysis. The application of the proposed methods to test systems shows that the results are satisfactory.
O processo de estimação de estado aplicado a sistemas elétricos de energia tem como objetivo fornecer uma imagem confiável, coerente e completa da operação do sistema, permitindo um monitoramento eficiente. A estimação de estado é uma das funções mais importantes dos sistemas de gerenciamento de energia. Neste trabalho são propostos métodos alternativos de estimação de estado para sistemas elétricos nos níveis de transmissão, subtransmissão e de distribuição. Para sistemas de transmissão são propostos dois métodos híbridos considerando a inserção das medições convencionais combinadas com medições fasoriais baseadas na unidade de medição fasorial (PMU - Phasor Measurement Unit). Para a estimação de estado em sistemas de subtransmissão é proposto um método alternativo que, na ocorrência de falhas nos medidores de potência ativa e/ou reativa das subestações, utiliza um modelo de previsão de carga baseado no critério de dias similares e na aplicação de redes neurais artificiais. Esse processo de previsão de carga é utilizado como gerador de pseudomedições na estimação de estado, que se dá através da propagação da medição fasorial fornecida por uma PMU alocada no barramento de fronteira. Para sistemas de distribuição o método de estimação de estado proposto consiste em aplicar o método de mínimos quadrados ponderados com restrições de igualdade, modificando-se o plano de medição e as variáveis de estado. Também é proposta uma metodologia para avaliação da disponibilidade dos canais de medições da PMU e o seu impacto na observabilidade do sistema. A aplicação dos métodos propostos a sistemas teste mostram que os resultados obtidos são satisfatórios.
Oqielat, Moa'ath Nasser. "Modelling water droplet movement on a leaf surface." Thesis, Queensland University of Technology, 2009. https://eprints.qut.edu.au/30232/1/Moa%27ath_Oqielat_Thesis.pdf.
Full textOqielat, Moa'ath Nasser. "Modelling water droplet movement on a leaf surface." Queensland University of Technology, 2009. http://eprints.qut.edu.au/30232/.
Full textPereira, Larissa Rocha. "Ajuste de curva B-spline fechada com peso." Universidade Federal de Uberlândia, 2014. https://repositorio.ufu.br/handle/123456789/14947.
Full textThe aim of this work is to develop a method of curve fitting using closed B-spline closed for application on reconstruction of cross-sections of objects. For this study specifically where the sections are closed curves, it has been implemented a method to close the curve B-spline curve, in such way that the curve is smooth on the closing point. The developed method is based on least squares approximation with weights, which defines that the curve should be as close as possible to the real curve. The weights in this case are responsible for the tightness of the approximation to each data points, whose points represent the coordinate of the object section that will be rebuild. Moreover, adjustments and impositions on the curve have been proposed so that it has a better result and represent more accurately the desired cross section. Particular characteristics of the curve were used to help enforce and define the settings. For the analysis, B-spline curves using the developed method, were obtained showing good results.
O objetivo desse trabalho é desenvolver um método de ajuste de curvas B-spline fechada para a aplicação na reconstrução de seções transversais de um objeto. Por especificamente nesse trabalho as seções serem seções fechadas, foi implementado um método para o fechamento da curva B-spline, de modo que a mesma possuía suavidade no seu fechamento. O método desenvolvido e utilizado foi baseado na aproximação por mínimos quadrados com pesos, que define que a curva obtida deva ser mais próxima possível da curva real. Os pesos nesse caso são responsáveis pela aproximação ou afastamento da curva em relação aos pontos dados, pontos esses que melhor representam as coordenadas da seção do objeto que se deseja reconstruir. Além disso, foram desenvolvidos ajustes e imposições na curva para que ela tivesse um melhor resultado e representasse de forma mais fiel a seção transversal desejada. Para a imposição e definição dos ajustes foram utilizadas características particulares da curva. Para a análise, curvas B-spline utilizando o método desenvolvido, foram traçadas e foram constatados os resultados desejados.
Mestre em Engenharia Mecânica
Zhang, Desheng. "The Effect of Psychometric Parallelism among Predictors on the Efficiency of Equal Weights and Least Squares Weights in Multiple Regression." Thesis, University of North Texas, 1996. https://digital.library.unt.edu/ark:/67531/metadc278996/.
Full textLy, Mouhamadou Moustapha. "Trois essais sur les effets de la politique budgétaire dans les pays en développement." Phd thesis, Université d'Auvergne - Clermont-Ferrand I, 2011. http://tel.archives-ouvertes.fr/tel-00606175.
Full textGulliksson, Mårten. "Algorithms for overdetermined systems of equations." Doctoral thesis, Umeå universitet, Institutionen för datavetenskap, 1993. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-111107.
Full textPavlík, Vít. "Sledování objektů ve videosekvencích." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2016. http://www.nusl.cz/ntk/nusl-255397.
Full textYeo, Wan Sieng. "Adaptive Soft Sensors for Non-Gaussian Chemical Process Plant Data Based on Locally Weighted Partial Least Square." Thesis, Curtin University, 2019. http://hdl.handle.net/20.500.11937/77028.
Full textCarvalho, Breno Elias Bretas de. "Estimação de estado: a interpretação geométrica aplicada ao processamento de erros grosseiros em medidas." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/18/18154/tde-29042013-114003/.
Full textThis work was proposed with the objective of implementing a computer program to estimate the states (complex nodal voltages) in an electrical power system (EPS) and apply alternative methods for processing gross errors (GEs), based on the geometrical interpretation of the measurements errors and the innovation concept. Through the geometrical interpretation, BRETAS et al. (2009), BRETAS; PIERETI (2010), BRETAS; BRETAS; PIERETI (2011) and BRETAS et al. (2013) proved mathematically that the measurement error is composed of detectable and undetectable components, and also showed that the detectable component of the error is exactly the residual of the measurement. The methods hitherto used, for processing GEs, consider only the detectable component of the error, then as a consequence, may fail. In an attempt to overcome this limitation, and based on the works cited previously, were studied and implemented two alternative methodologies for process measurements with GEs. The first one is based on the direct analysis of the components of the errors of the measurements, the second one, in a similar way to the traditional methods, is based on the analysis of the measurements residuals. However, the differential of the second proposed methodology lies in the fact that it doesn\'t consider a fixed threshold value for detecting measurements with GEs. In this case, we adopted a new threshold value (TV ) characteristic of each measurement, as presented in the work of PIERETI (2011). Furthermore, in order to reinforce this theory, we propose an alternative way to calculate these thresholds, by analyzing the geometry of the probability density function of the multivariate normal distribution, relating to the measurements residuals.
Zhang, Zongjun. "Adaptive Robust Regression Approaches in data analysis and their Applications." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1445343114.
Full textGaspard, Guetchine. "FLOOD LOSS ESTIMATE MODEL: RECASTING FLOOD DISASTER ASSESSMENT AND MITIGATION FOR HAITI, THE CASE OF GONAIVES." OpenSIUC, 2013. https://opensiuc.lib.siu.edu/theses/1236.
Full textHaberstich, Cécile. "Adaptive approximation of high-dimensional functions with tree tensor networks for Uncertainty Quantification." Thesis, Ecole centrale de Nantes, 2020. http://www.theses.fr/2020ECDN0045.
Full textUncertainty quantification problems for numerical models require a lot of simulations, often very computationally costly (in time and/or memory). This is why it is essential to build surrogate models that are cheaper to evaluate. In practice, the output of a numerical model is represented by a function, then the objective is to construct an approximation.The aim of this thesis is to construct a controlled approximation of a function while using as few evaluations as possible.In a first time, we propose a new method based on weighted least-squares to construct the approximation of a function onto a linear approximation space. We prove that the projection verifies a numerical stability property almost surely and a quasi-optimality property in expectation. In practice we observe that the sample size is closer to the dimension of the approximation space than with existing weighted least-squares methods.For high-dimensional approximation, and in order to exploit potential low-rank structures of functions, we consider the model class of functions in tree-based tensor formats. These formats admit a multilinear parametrization with parameters forming a tree network of low-order tensors and are therefore also called tree tensor networks. In this thesis we propose an algorithm for approximating functions in tree-based tensor formats. It consists in constructing a hierarchy of nested subspaces associated to the different levels of the tree. The construction of these subspaces relies on principal component analysis extended to multivariate functions and the new weighted least-squares method. To reduce the number of evaluations necessary to build the approximation with a certain precision, we propose adaptive strategies for the control of the discretization error, the tree selection, the control of the ranks and the estimation of the principal components
Oliveira, Bráulio César de. "Estimação de estados em sistemas de distribuição: uma abordadgem trifásica e descentralizada." Universidade Federal de Juiz de Fora (UFJF), 2016. https://repositorio.ufjf.br/jspui/handle/ufjf/3141.
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O presente trabalho tem por objetivo apresentar uma metodologia para estimação de estados em sistemas de distribuição de energia elétrica. São utilizadas como variáveis de estado as correntes nos ramos. As medições são obtidas por meio de medições fasoriais sincronizadas(PhasorMeasurementUnits-PMUs),sendoqueostiposdemedidasadvindos desses equipamentos são as tensões nodais e as correntes nos ramos. A abordagem é trifásica, portanto representa as características próprias de um sistema de distribuição. A metodologia consiste em resolver um problema de otimização não linear cuja função objetivo associa o erro quadrático das medidas em relação aos estados estimados sujeito às restrições de carga das barras da rede que não possuem PMUs instaladas baseadas em estimativas de cargas obtidas para o instante “t-1”, partindo-se da premissa que em curtos intervalos de tempo a carga não sofre grandes variações, sendo esta em conjunto com a abordagem trifásica as principais contribuições deste trabalho. Outra contribuição do trabalho é a descentralização, com esta técnica pode-se dividir uma determinada rede em vários subsistemas que podem ser resolvidos de forma separada e independente. Isso torna o processo mais rápido do ponto de vista computacional além de permitir o uso do processamento paralelo, visto que já existe um paralelismo natural entre as tarefas que devem ser resolvidas. Outra vantagem da divisão em subsistemas reside no fato do monitoramento de áreas de interesse. Para utilizar a descentralização foi proposta uma alternativa de alocação de PMUs que consiste em posicionar duas unidades em cada ramificação do sistema, uma no começo e outra no final do trecho, procurando utilizar o menor número possível e que não comprometa a qualidade dos estados estimados. A resolução do problema de otimização é realizada através da implementação computacional do Método de Pontos Interiores com Barreira de Segurança (Safety Barrier Interior Point Method - SFTB - IPM) proposto na literatura especializada. As medidas das PMUs foram obtidas através de um Fluxo de Potência Trifásico via Injeção de Correntes (FPTIC). Foram realizadas diversas simulações variando-se o percentual da carga e os resultados obtidos foram comparados com outra metodologia existente na literatura e com os valores verdadeiros que foram obtidos através do FPTIC para as barras não monitoradas. Foram tambémcomparadosotempocomputacionalentreaexecuçãoserialeaexecuçãoutilizando o processamento paralelo. Os testes mostraram bons resultados o que torna a metodologia proposta aplicável na supervisão de sistemas de distribuição.
This work aims to present a methodology for static state estimation in electric power distribution systems. Branch currents are used as state variables. Measurements are obtained by means of Phasor Measurement Units (PMUs), in which voltage and current branches measurements are used. The approach is three-phase, thus represents the distribution system characteristics. The methodology consists of solving a nonlinear optimization problem minimizing a quadratic objective function associated with the estimated measurements and states subject to load constraints for the non monitored loads based on estimated load obtained from the ‘t-1’ instant, starting from the assumption that in short time intervals the load does not have large variations, which together with the the three-phase approach are the main contributions of this work. Another contribution of this work is the descentralided approach, with this assumption the network can be divided into several subnetworks that can be solved separately and independently. This speeds up the process of being solved from a computational point of view and allows the use of parallel processing, since there is already a natural parallelism among tasks to be solved. Another advantage of the division into subsystems is the fact that the monitoring areas of interest. With the aim of allowing the decentralization was proposed PMUs allocation strategy that consists of allocating two units for each lateral feeder, one at the beginning and one at the end, trying to use as little PMUs as possible in such a way that the quality of the estimated states are not compromised. The resolution of the optimization problem is done through a computer implementation of Interior Point Method with Security Barrier (SFTB - IPM) proposed in the literature. The PMUs measurements were emulated using a Three-PhasePowerFlowusingtheCurrentInjectionmethod(FPTIC).Severalsimulations were performed varying the load percentage and the results obtained were compared with other existing methodology in literature and also the true values that were obtained from the FPTIC to non monitored loads. The computational time using serial and parallel processing were also compared. Results show good results which makes the proposed methodology applicable in monitoring distribution systems.
Chen, Jiaxiong. "Power System State Estimation Using Phasor Measurement Units." UKnowledge, 2013. http://uknowledge.uky.edu/ece_etds/35.
Full textBlandin, Vassili. "Estimation de paramètres pour des processus autorégressifs à bifurcation." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00842856.
Full textAlves, Guilherme de Oliveira. "Uma nova metodologia para estimação de estados em sistemas de distribuição radiais utilizando PMUs." Universidade Federal de Juiz de Fora, 2015. https://repositorio.ufjf.br/jspui/handle/ufjf/1528.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O presente trabalho tem por objetivo apresentar uma nova metodologia para estimação estática de estados em sistemas de distribuição de energia elétrica que estima as correntes nos ramos como variáveis de estado utilizando medições de tensão e corrente de ramo fasoriais oriundas de unidades de medição fasorial (Phasor Measurement Units - PMUs). A metodologia consiste em resolver um problema de otimização não linear minimizando uma função objetivo quadrática associada com as medições e estados estimados sujeito às restrições de carga das barras da rede que não apresentam PMUs instaladas baseadas em dados históricos, sendo esta a principal contribuição deste trabalho. Uma proposta de alocação de PMUs também é apresentada e que consiste em alocar duas unidades em cada ramificação do sistema, uma no começo e outra no final do trecho, procurando utilizar o menor número possível e que não comprometa a qualidade dos estados estimados. A resolução do problema de otimização é realizada de duas formas, através da ‘toolbox fmincon’ do software Matlab, que é uma ferramenta muito utilizada na resolução de problemas de otimização, e através da implementação computacional do Método de Pontos Interiores com Barreira de Segurança (Safety Barrier Interior Point Method - SFTB - IPM) proposto na literatura utilizada. Durante o processo de estimação de estados são utilizadas medidas obtidas através de um fluxo de potência que simulam as PMUs instaladas nos sistemas analisados variando o carregamento de cada sistema em torno da sua média histórica de carga até atingir os limites superior e inferior estabelecidos, sendo verificado o comportamento do estimador de estados perante a ocorrência de ruídos brancos nas medidas de todos os sistemas analisados. Foram analisados um sistema de distribuição tutorial de 15 barras e três sistemas encontrados na literatura contendo 33, 50 e 70 barras respectivamente. No sistema tutorial e no de 70 barras foram incluídas unidades de geração distribuída para se verificar o comportamento do estimador de estados. Todos os resultados do processo de estimação de estados são obtidos com os dois métodos de resolução apresentados e são comparados o desempenho de cada método, principalmente em relação ao tempo computacional. Todos os resultados obtidos foram validados usando um programa de fluxo de potência convencional e apresentam boa precisão com valor de função objetivo baixo mesmo na presença de ruídos nas medidas refletindo de maneira confiável o real estado do sistema de distribuição, o que torna a metodologia proposta atraente.
This work aims at presenting a new methodology for static state estimation in electric power distribution systems which estimates the branch currents as state variables using voltage measurements and current phasor branch obtained from phasor measurement units (Phasor Measurement Units - PMUs). The methodology consists of solving a nonlinear optimization problem minimizing a quadratic objective function associated with the estimated measurements and states, subject to load constraints for the non monitored loads based on historical data, which is the main contribution of this work. A PMU allocation strategy is presented which consists of allocating two PMUs for each system branch, one at the beginning and another at the end, trying to use as little PMUs as possible in such a way that the quality of the estimated states are not compromised. The solution of the optimization problem is obtained through two ways, the first is the toolbox ‘fmincon’ from Matlab solver software which is a widely used tool in the optimization problem. The second is a computer implementation of interior point method with security barrier (SFTB - IPM) proposed in the literature. Comparisons of computing times and results obtained with both methods are shown. A power flow program is used to obtain the voltages and branch currents in order to emulate the PMUs data in the state estimation process. Additionaly the non monitored loads are varied from the minimum bounds to their maximum, allowing white noise errors from the PMUs measurements. A tutorial test system of 15 buses is fully explored and three IEEE test systems of 33, 50 and 70 buses are used to show the effectiveness of the proposed methodology. For the tutorial and 70 bus systems, distribued generation units were included to see the state estimator behavior. All results from the state estimation process are obtained considering the two presented solving methods and the computing times performance compared. The results obtained were validated using a conventional power flow program and have good accuracy with low objective function value even in the presence of white noise errors in the measurements reflecting the reliability of the proposed methodology, making it very attractive for distribution system monitoring.
Vieira, Camila Silva. "Processamento de erros grosseiros através do índice de não-detecção de erros e dos resíduos normalizados." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/18/18154/tde-22032018-144505/.
Full textThis dissertation deals with the problem of Gross Errors processing based on the use of the so-called Undetectability Index, or just UI. This index was developed recently and it is capable to classify the measurements according to their characteristics of not reflecting their errors into the residuals of the weighted least squares state estimation process. Gross errors in measurements with higher UIs are very difficult to be detected by methods based on the residual analysis, as the errors in those measurements are masked, i.e., they are not reflected in the residuals. Initially, this dissertation demonstrates that a non-detectable gross error (error in a measurement with high UI) may affect more the accuracy of the estimated state variables than a detectable gross error (error in a measurement with low UI). Therefore, justifying the importance of studies that make possible gross errors processing in measurements with high UI. In this dissertation, several computational simulations are carried out to analyze the influence of different weights of measurements in the UI index and also in the accuracy of the estimated state variables. It is chosen a way that stood out as the most appropriate for weighing the measurements. Finally, in this dissertation, the studies referring to the UI is extended for a hybrid weighted least squares state estimator.
Sundin, Daniel. "Natural gas storage level forecasting using temperature data." Thesis, Linköpings universitet, Produktionsekonomi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-169856.
Full textEsquincalha, Agnaldo da Conceição. "Estimação de parâmetros de sinais gerados por sistemas lineares invariantes no tempo." Universidade do Estado do Rio de Janeiro, 2009. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=1238.
Full textNesta dissertação é apresentado um estudo sobre a recuperação de sinais modelados por somas ponderadas de exponenciais complexas. Para tal, são introduzidos conceitos elementares em teoria de sinais e sistemas, em particular, os sistemas lineares invariantes no tempo, SLITs, que podem ser representados matematicamente por equações diferenciais, ou equações de diferenças, para sinais analógicos ou digitais, respectivamente. Equações deste tipo apresentam como solução somas ponderadas de exponenciais complexas, e assim fica estabelecida a relação entre os sistemas de tipo SLIT e o modelo em estudo. Além disso, são apresentadas duas combinações de métodos utilizadas na recuperação dos parâmetros dos sinais: métodos de Prony e mínimos quadrados, e métodos de Kung e mínimos quadrados, onde os métodos de Prony e Kung recuperam os expoentes das exponenciais e o método dos mínimos quadrados recupera os coeficientes lineares do modelo. Finalmente, são realizadas cinco simulações de recuperação de sinais, sendo a última, uma aplicação na área de modelos de qualidade de água.
A study on the recovery of signals modeled by weighted sums of complex exponentials complex is presented. For this, basic concepts of signals and systems theory are introduced. In particular, the linear time invariant systems (LTI Systems) are considered, which can be mathematically represented by differential equations or difference equations, respectively, for analog or digital signals. The solution of these types of equations is given by a weighted sum of complex exponentials, so the relationship between the LTI Systems and the model of study is established. Furthermore, two combinations of methods are used to recover the parameters of the signals: Prony and least squares methods, and Kung and least squares methods, where Prony and Kung methods are used to recover the exponents of the exponentials and the least square method is used to recover the linear coefficients of the model. Finally, five simulations are performed for the recovery of signals, the last one being an application in the area of water quality models.
Chen, Long. "Méthodes itératives de reconstruction tomographique pour la réduction des artefacts métalliques et de la dose en imagerie dentaire." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112015/document.
Full textThis thesis contains two main themes: development of new iterative approaches for metal artifact reduction (MAR) and dose reduction in dental CT (Computed Tomography). The metal artifacts are mainly due to the beam-hardening, scatter and photon starvation in case of metal in contrast background like metallic dental implants in teeth. The first issue concerns about data correction on account of these effects. The second one involves the radiation dose reduction delivered to a patient by decreasing the number of projections. At first, the polychromatic spectra of X-ray beam and scatter can be modeled by a non-linear direct modeling in the statistical methods for the purpose of the metal artifacts reduction. However, the reconstruction by statistical methods is too much time consuming. Consequently, we proposed an iterative algorithm with a linear direct modeling based on data correction (beam-hardening and scatter). We introduced a new beam-hardening correction without knowledge of the spectra of X-ray source and the linear attenuation coefficients of the materials and a new scatter estimation method based on the measurements as well. Later, we continued to study the iterative approaches of dose reduction since the over-exposition or unnecessary exposition of irradiation during a CT scan has been increasing the patient's risk of radio-induced cancer. In practice, it may be useful that one can reconstruct an object larger than the field of view of scanner. We proposed an iterative algorithm on super-short-scans on multiple scans in this case, which contain a minimal set of the projections for an optimal dose. Furthermore, we introduced a new scanning mode of variant angular sampling to reduce the number of projections on a single scan. This was adapted to the properties and predefined interesting regions of the scanned object. It needed fewer projections than the standard scanning mode of uniform angular sampling to reconstruct the objet. All of our approaches for MAR and dose reduction have been evaluated on real data. Thanks to our MAR methods, the quality of reconstructed images was improved noticeably. Besides, it did not introduce some new artifacts compared to the MAR method of state of art NMAR [Meyer et al 2010]. We could reduce obviously the number of projections with the proposed new scanning mode and schema of super-short-scans on multiple scans in particular case
Annamalai, Andy S. K. "An adaptive autopilot design for an uninhabited surface vehicle." Thesis, University of Plymouth, 2014. http://hdl.handle.net/10026.1/3100.
Full textBenamar, Mohamed Amine. "Développement d’une approche numérique et expérimentale par la mesure VLD pour la propagation acoustique mutimodale en conduit avec écoulement." Thesis, Compiègne, 2021. http://www.theses.fr/2021COMP2624.
Full textLaser Doppler Velocimetry (LDV) is a non-intrusive measurement of particle velocity classically used in fluid mechanics. The acoustic velocity is a very important quantity in acoustics for the characterization of acoustic propagation fields, which is essential for the understanding of certain propagation phenomena in near walls or for complex geometries. The DUCAT bench installed in the laboratory of the Acoustics and Vibration team of the University of Technology of Compiègne aimed at characterizing the acoustic performances of various acoustic absorption systems such as SDOF or metallic porous materials for aeronautical uses through the measurement of the acoustic velocity and pressure through two automated probes containing a hot wire sensor as well as a microphone with ogive. The objective of this thesis is to allow the measurement of acoustic velocity in multimodal propagation and in the presence of flow using the VLD. The signal measured by the VLD is randomly sampled and has a fairly large background noise due to the presence of flow in the duct. The complex nature of the measured signal requires special signal processing methods to extract the acoustic velocity that is important to us. The first part of this thesis presents a benchmark of the different methods available in the literature and their validity for the current experimental conditions of the DUCAT bench. A simulation of the measured VLD signal is developed as a reference to validate the methods, whether they are spectral or temporal. The weighted least squares method is finally selected and adapted following this study for the estimation of the various acoustic parameters from the raw signal. The second part concerns the presentation of the numerical tools used or developed for the simulation of the acoustic propagation in infinite ducts. The main numerical tool is an aeroacoustic finite element code developed in the lab based on Galbrun’s equations coupled to a virtual absorbing layer called PML (Perfect Matched Layer). Due to the presence of the PML, the numerical solution of the inverse problem becomes complicated, which led us to develop a code for solving nonlinear eigenvalue problems based on the Integral Contour method. The third part of this work presents the different components of the modified version of the bench as well as the characteristics of these different components. The bench allows the experimentation of multimodal acoustic propagation (up to 5000 Hz) in the presence of a suction/expiration flow that can reach a speed of Mach 0.25. The fourth and last part, presents a protocol of experimental numerical validation of all the tools presented and developed. The test/calculation comparisons are presented for a multimodal propagation in a straight duct at first. The results allow to conclude on the efficiency of the measurement and signal processing system with a relative error lower than 1 dB. The same protocol is then used for the experimental study of the acoustic trapped modes in the case of a cylindrical duct with an abrupt change of section
Deilami, Kaveh. "Modelling the urban heat island intensities of alternative urban growth management policies in Brisbane." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/107656/1/Kaveh_Deilami_Thesis.pdf.
Full textDestino, G. (Giuseppe). "Positioning in wireless networks:non-cooperative and cooperative algorithms." Doctoral thesis, Oulun yliopisto, 2012. http://urn.fi/urn:isbn:9789514299742.
Full textTiivistelmä Viime vuosina paikkatietoisuudesta on tullut eräs merkittävä avainteknologia mobiili- ja sensoriverkkojen tulevaisuuden kehitykselle. Paikkatieto mahdollistaa useiden verkko-optimointistrategioiden sekä palveluiden kehittämisen. Kuitenkin tarkan paikkatiedon määrittäminen, esimerkiksi kohteen koordinaattien, on edelleen vaativa tehtävä ja robustit algoritmit vaativat kehittämistä. Tässä väitöskirjassa keskitytään etäisyyspohjaisten, yhteistoiminnallisten sekä ei-yhteistoiminnallisten, algoritmien kehittämiseen. Algoritmit pohjautuvat parametrittömään ei-bayesilaiseen viitekehykseen, erityisesti painotetun pienimmän neliösumman (WLS) optimointimenetelmään. Väitöskirjassa tutkitaan WLS ongelmaa teoreettisesti ja osoitetaan sen optimaalisuus todeksi tarkastelemalla sen suhdetta suurimman todennäköisyyden (ML) estimaattoriin. Lisäksi tässä työssä tutkitaan perustavanlaatuisia raja-arvoja sekä johdetaan yhtäpitävyysehdot luomalla yhteys euklidisen geometrian ja inferenssiteorian välille. Väitöskirjassa myös johdetaan suljettu ilmaisu etäisyyspohjaiselle Cramér-Rao -alarajalle (CRLB) sekä esitetään yhtälöt, jotka karakterisoivat informaation liittämisen Fisherin informaatiomatriisiin. Väitöskirjassa ehdotetaan uutta viitekehystä, nimeltään etäisyyden supistaminen, robustin ei-yhteistoiminnallisen paikannustekniikan perustaksi. Tässä työssä todistetaan, että etäisyyden supistaminen pienentää globaali minimi -ongelmaa ja jäsennetty etäisyyden supistaminen johtaa lähes optimaaliseen suorituskykyyn vaikeissa radiokanavan olosuhteissa. Näiden tulosten pohjalta väitöskirjassa esitetään, kuinka klassiset algoritmit, kuten painotetun keskipisteen (WC) sekä epälineaarinen pienimmän neliösumman (NLS) menetelmät, voidaan muokata ottamaan huomioon etäisyysmittauksen harha. Yhteistoiminnalliseksi paikannusmenetelmäksi johdetaan uusi, lähes optimaalinen algoritmi, joka on kompleksisuudeltaan matala. Algoritmi on etäisyyspohjainen globaalin optimoinnin menetelmä ja sitä käytetään keskitetyissä ja hajautetuissa paikannusjärjestelmissä. Lisäksi tässä työssä ehdotetaan tehokasta painotusstrategiaa ottamaan huomioon mittausharha. Strategia pitää sisällään dispersiopainon, joka tallentaa häiriön aiheuttaman vaikutuksen maksimoiden samalla informaation hajonnan, sekä geometrisen sakkokertoimen, joka rankaisee harhattomuuden ennakko-oletuksesta. Lopuksi väitöskirjassa esitetään tulokset kokeellisista mittauksista, joissa ehdotettuja algoritmeja käytettiin kaupallisissa erittäin laajakaistaisissa (UWB) laitteissa
Hussain, Sibt Ul. "Apprentissage machine pour la détection des objets." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00722632.
Full textSheu, Yu Jen, and 許玉珍. "Compare M-Smoothers with Iterative Weighted Least Squares." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/99556913680728148219.
Full text國立東華大學
應用數學系
89
Abstract An important operation in image processing is denoising, where a digital signal is extracted from data consisting of the signal plus noise. And the goal is to recover as much of the signal as possible from noisy data. A well-known method that accomplishes some of these goals is classical smoothing; that is , local averaging. But smoothing is inappropriate when the image has jumps or edges (which happens very frequently) between regions, because smoothing tends to blur the edges. The fact that the smooth is continuous means it can not properly capture the discontinuous jumps of underlying signal. The purpose of this thesis is to discuss that improve the edge - preserving M-smoothers and iterative weighted least squares. Compare M-smoothers with iterative weighted least squares by bias、standard deviation、mean square error (MSE) and another methods. Key Words:image processing;denoising;edge - preserving; M-smoothers;iterative weighted least squares。
Lin, Hon-Ron, and 林鴻蓉. "Weighted Least Squares Analysis for Repeated Ordinal Data." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/07172440518309483691.
Full text中原大學
應用數學研究所
94
A new approach to analyze the repeated outcomes is proposed. By transforming each of subjects to a rank component vector and then applying the multivariate central limit theory and the delta method, the proposed method can be used to test the difference within group and between groups. This methodology makes no assumptions concerning the time dependence among the repeated measurements. It is based only on the multinomial distribution for count data. The practical examples testing the linear and quadratic components of the time effect illustrate the use of the proposed method. The underlying model for the weighted least squares approach is the multinomial distribution. Although the distribution assumptions are much weaker, one still must make some basic assumptions concerning the marginal distributions at each time point. In addition, the assumptions of specific ordinal data methods such as the proportional odds model may be inappropriate. In all of these situations, nonparametric methods for analyzing repeated measurements may be of use. The proposed method is to assign ranks to repeated measurements from the smallest value to the largest value for each subject. The vector of rank means can be computed by the linear transformation of these ranks. Then the multivariate central limit theory and the delta method are applied to obtain the test statistics. The methods make no assumptions concerning the distribution of the response variable. Two practical examples will be illustrated the use of the proposed method.