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Estimating the slope in the simple linear errors-in-variables modelMusekiwa, Alfred. 13 August 2012 (has links)
M.Sc. / In this study we consider the problem ofestiniating the slope in the simple linear errors-in-variables model. There are two different types of relationship that can he specified in the errors-in-variables model: one that specifies a functional linear relationship and one describing a structural linear relationship. The different relationship specifications can lead to different estimators with different properties. These two specifications are highlighted in this study. A least squares solution (to the estimation of the slope) is given. The problem of finding the maximum likelihood solution to these two specifications is addressed. It is noted that an unidentifiability problem arises in this attempt. The solution is seen to lie in making assumptions on the error variances. Interval estimation for the slope parameter is discussed. It is noted that any interval estimator of the slope whose length is always finite will have a confidence coefficient of zero. Various interval estimation methods are reviewed but emphasis is mainly on the investigation of a bootstrap procedure for estimating the confidence interval for the slope parameter β. More specifically, the Linder and Babu (1994) (bootstrap) method for the structural relationship model with known variance ratio is investigated here. The error distributions were assumed normal. A simulation study based on this paper is carried out. The results in the simulation study show that this bootstrap procedure performs well in comparison with the normal theory estimates for normally distributed data, that is, it has better coverage accuracy than the normal approximation.
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Zakázková webová aplikace s informačním systémem malé firmy / Custom web application with information system for small companyPecharová, Karolína January 2017 (has links)
This thesis is concerning the creation of individual information system for small house-keeping business. The goal is to obtain a system that would meet the needs of the company. The paper focuses on information system design and development in its own by using Java.
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On Some Test Statistics for Testing the Population Skewness and Kurtosis: An Empirical StudyGuo, Yawen 26 August 2016 (has links)
The purpose of this thesis is to propose some test statistics for testing the skewness and kurtosis parameters of a distribution, not limited to a normal distribution. Since a theoretical comparison is not possible, a simulation study has been conducted to compare the performance of the test statistics. We have compared both parametric methods (classical method with normality assumption) and non-parametric methods (bootstrap in Bias Corrected Standard Method, Efron’s Percentile Method, Hall’s Percentile Method and Bias Corrected Percentile Method). Our simulation results for testing the skewness parameter indicate that the power of the tests differs significantly across sample sizes, the choice of alternative hypotheses and methods we chose. For testing the kurtosis parameter, the simulation results suggested that the classical method performs well when the data are from both normal and beta distributions and bootstrap methods are useful for uniform distribution especially when the sample size is large.
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On Resampling Schemes for Uniform PolytopesQi, Weinan January 2017 (has links)
The convex hull of a sample is used to approximate the support of the underlying
distribution. This approximation has many practical implications in real life. For
example, approximating the boundary of a finite set is used by many authors in environmental studies and medical research. To approximate the functionals of convex hulls, asymptotic theory plays a crucial role. Unfortunately, the asymptotic results are mostly very complicated. To address this complication, we suggest a consistent bootstrapping scheme for certain cases. Our resampling technique is used for both semi-parametric and non-parametric cases. Let X1,X2,...,Xn be a sequence of i.i.d. random points uniformly distributed on an unknown convex set. Our bootstrapping scheme relies on resampling uniformly from the convex hull of X1,X2,...,Xn. In this thesis, we study the asymptotic consistency of certain functionals of convex hulls. In particular, we apply our bootstrapping technique to the Hausdorff distance between the actual convex set and its estimator. We also provide a conjecture for the application of our bootstrapping scheme to Gaussian polytopes. Moreover, some other relevant consistency results for the regular bootstrap are developed.
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Análise das incertezas das estimativas dos parâmetros de crescimento e mortalidade utilizados na avaliação de estoques de peixes recifais no Nordeste do BrasilFerreira Teixeira, Simone January 2004 (has links)
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Previous issue date: 2004 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O manejo pesqueiro, tradicionalmente, baseia-se em modelos de avaliação de estoque objetivando indicar recomendações para a explotação ótima de uma determinada espécie, sem que ocorra o colapso desta. Os modelos de avaliação de estoque requerem em seus cálculos dados biológicos da população provenientes dos parâmetros de crescimento e das taxas de mortalidade. As expressões matemáticas desses cálculos apresentam como premissas básicas suposições que metodologicamente ou biologicamente nem sempre são todas cumpridas, gerando vícios/erros nos resultados obtidos. Essas incertezas que envolvem a avaliação dos estoques pesqueiros podem dificultar a tomada de decisão acerca das capturas futuras. O manejo dos recursos pesqueiros, utilizando os métodos tradicionais, tem se mostrado ineficiente, acarretando no colapso de muitas pescarias. A partir da década de 70 e devido ao colapso das pescarias, a aplicação de outras estatísticas, como o método de bootstrap, tem possibilitado a investigação das incertezas das estimativas provenientes das estatísticas clássicas e rotineiramente utilizadas. Com o objetivo de investigar a exatidão das estimativas dos parâmetros biológicos de crescimento e taxas de mortalidade, da influência da freqüência reduzida de peixes jovens na amostra e da influência do acréscimo amostral de adultos e velhos no estoque explotado, foram realizadas reamostras, pelo método de bootstrap, para se estimar as incertezas destas estimativas e simular suas conseqüências nos modelos de avaliação de estoques. Para a aplicação desta metodologia foi tomado como estudo de caso a guaiúba Lutjanus chrysurus, capturada ao longo da costa nordestina, entre as profundidades de 47 a 400 m e amostrada pelo Programa Recursos Vivos da Zona Econômica Exclusiva (REVIZEE Score/NE), entre os anos de 1996 e 2000. Os dados de idade, obtidos por meio da leitura de 660 otólitos de L. chrysurus, foram utilizados para a elaboração de um conjunto de dados de idade e comprimento furcal. O método de bootstrap foi utilizado para gerar novos
conjuntos de dados de idade e comprimento furcal, a partir da amostra original, sendo desenvolvido dois programas em linguagem C para realizar estas reamostras. O modelo utilizado para estimar os parâmetros de crescimento em comprimento foi a equação de von Bertalanffy; as taxas de mortalidade foram estimadas pelos métodos de Pauly, Ralston e Jensen; os modelos preditivos utilizados foram o Modelo de Rendimento por Recruta de Beverton & Holt e o Modelo de Biomassa por Recruta de Beverton & Holt; e, as incertezas das estimativas dos parâmetros de crescimento e das taxas de mortalidade foram analisadas por meio do intervalo de confiança do bootstrap padrão e do vício relativo. Os resultados do presente estudo indicaram que, dentre os parâmetros de crescimento, crescimento assintótico em comprimento (L∞), taxa de crescimento (k) e idade teórica da espécie com comprimento zero (t0), o k é o parâmetro estimado com maior variabilidade e que mais influencia a estimação da taxa de mortalidade natural (M); que os maiores vícios nas estimativas dos parâmetros de crescimento e mortalidade foram quando se simulou a redução dos jovens da amostra e o acréscimo dos adultos e velhos, sugerindo que a ausência de jovens nas amostras acarreta em sérios erros nas estimativas dos parâmetros de crescimento e das taxas de mortalidade; que a avaliação de estoques não deve ser somente baseada em modelos de biomassa por recruta, visto que os vícios relativos sempre foram maiores na biomassa do que no rendimento relativo por recruta; e, que a técnica de reamostragem deve ser considerada como uma ferramenta rotineira e essencial nas estimativas dos parâmetros de crescimento, taxas de mortalidade e na avaliação de estoques, já que o melhor rendimento relativo por recruta e biomassa relativa por recruta foi proveniente da análise das incertezas. Baseado nos dados obtidos sugere-se a redução da taxa de mortalidade por pesca de L. chrysurus a fim de evitar o colapso desta espécie
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Kostnader av frekvensreglering på en kaplanturbin / Cost of Frequency regulation for a Kaplan TurbineBurström, Victor, Kashwan, Ahmed January 2020 (has links)
Spelplanen för energiproducenter kommer inom de kommande årtionden förändras och företagen kommer ställas inför stora utmaningar. Kärnkraften kommer att fasas bort till 2040 enligt ett Regeringsbeslut, något som kommer kräva en utbyggnad av de förnyelsebara energikällorna som vind- och solkraft. Det är energikällor som har betydligt större variation där väder påverkar produktionen samtidigt som det är svårt att planera och prognostisera. Det kan således tillkomma och falla bort elproduktion på nätet under kort tid om det som exempel skulle sluta blåsa under en timme. Ett fungerande elsystem bygger på att det alltid ska finnas en balans mellan elproduktion och elanvändning. Denna balans mäts i frekvens på elnätet och Norden har en nominell frekvens på 50,0Hz, något som påverkas av ett underskott eller överskott av antingen produktion eller konsumtion. En utbyggnad i vind- och solkraft kan således ställa högre krav på vattenkraften som med sin goda planeringsförmåga fungerar utmärkt som frekvensreglerande kraftkälla. Inom vattenkraftsproduktion finns det två produktkategorier som energiproducenter kan sälja sin producerade el som normal drift och frekvensreglering, där den förstnämna är den som majoriteten av intäkterna står för. Eftersom det finns stora kostnader relaterade till slitage som uppstår i en turbin vid drift är det i Skellefteå Krafts intresse att studera de kostnader som är orsakade av frekvensreglering. För detta har olika utjämningsfunktioner utnyttjats för att klassificera data som antingen normal drift eller frekvensreglering, för att sedan beräkna vad frekvensregleringen motsvarar i slitage på ett aggregat. Skellefteå Kraft har i Augusti 2019 implementerat ett system som lagrar driftdata. Då en förväntad livslängd av en kaplanturbin är mellan 40 och 50 år krävdes det då mer data för att kunna dra rimliga slutsatser. Eftersom en begränsning finns gällande mängden av data, används omsamplinstekniken Block bootstrap för simulering av driftdata, vilket är nödvändigt för att kunna utföra en livslängdsanalys. Slutsatsen var att trots att frekvensreglering stod för drygt 95% av slitaget stod det endast för 8-9% av intäkterna, men att det ändå hade en vinstmarginal på 2-3 gånger kostnaden. En livslängdssimulering på 40 år medförde ett slitage på drygt 420 mikrometer för det Yttre löpskoveltappslagret (det lager som slits mest), vilket ligger inom rimligt slitage med hänsyn till designvärdet.
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Analytic Conformal Bootstrap in 2D CFT / 2次元共形ブートストラップの解析的手法Kusuki, Yuya 23 March 2021 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第22996号 / 理博第4673号 / 新制||理||1670(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 高柳 匡, 教授 杉本 茂樹, 教授 田中 貴浩 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM
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Inovace bezplatného registru jízdních kol / Innovation of the Free Bike RegistryPetričko, Michal January 2020 (has links)
This diploma thesis deals with the creating of a web apllication using the Nette framework for the KradenaKola.cz project. Theoretical background is utilized to describe the technologies used in development. Based on analysis of the request, the entire web application is created both functionally and visually.
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Low-Complexity Regularization Algorithms for Image DeblurringAlanazi, Abdulrahman 11 1900 (has links)
Image restoration problems deal with images in which information has been degraded
by blur or noise. In practice, the blur is usually caused by atmospheric turbulence, motion, camera shake, and several other mechanical or physical processes.
In this study, we present two regularization algorithms for the image deblurring problem.
We first present a new method based on solving a regularized least-squares (RLS)
problem. This method is proposed to find a near-optimal value of the regularization parameter in the RLS problems. Experimental results on the non-blind image deblurring problem are presented. In all experiments, comparisons are made with three benchmark methods. The results demonstrate that the proposed method clearly outperforms the other methods in terms of both the output PSNR and structural similarity, as well as the visual quality of the deblurred images. To reduce the complexity of the proposed algorithm, we propose a technique based on
the bootstrap method to estimate the regularization parameter in low and high-resolution images. Numerical results show that the proposed technique can effectively reduce the computational complexity of the proposed algorithms. In addition, for some cases where the point spread function (PSF) is separable, we propose using a Kronecker product so as to reduce the computations.
Furthermore, in the case where the image is smooth, it is always desirable to replace the regularization term in the RLS problems by a total variation term. Therefore, we propose a novel method for adaptively selecting the regularization parameter in a so-called square root regularized total variation (SRTV). Experimental results demonstrate that our proposed method outperforms the other benchmark methods when applied to smooth images in terms of PSNR, SSIM and the restored image quality.
In this thesis, we focus on the non-blind image deblurring problem, where the blur
kernel is assumed to be known. However, we developed algorithms that also work in the blind image deblurring. Experimental results show that our proposed methods are robust enough in the blind deblurring and outperform the other benchmark methods in terms of both output PSNR and SSIM values.
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Webová aplikace a administrační systém pro strojírenskou firmuJanulík, Petr January 2017 (has links)
This diploma thesis deals with designing and implementation of administration system for Metal Ryspol, s. r. o. In the implementation phase, modern development technologies were used, such as MVC architecture and responsive web design.
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