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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.
151

Lärarstöd för orkestrering av produktiva matematiska diskussioner : Analys av matematikläromedel för gymnasiet

Allard, Cecilia January 2024 (has links)
Syftet med föreliggande studie var att undersöka förekomsten av stöd för lärare i läromedel att orkestrera produktiva matematiska diskussioner i undervisningen. En läromedelsanalys genomfördes baserad på ett analysverktyg med utgångspunkt i Steins m. fl. (2008) modell för produktiva matematiska helklassdiskussioner. Analysfrågor för att undersöka förekomsten av stöd för de fem praktikerna i modellen, förutse, övervaka, välja, ordningsföljd och sammankoppla, togs fram. Analysfrågorna applicerades på fyra läromedel för gymnasiekursen matematik 2b. Resultatet av analysen visade att det i alla undersökta läromedel förekom någon form av lärarstöd för produktiva matematiska diskussioner enligt Steins m. fl. (2008) modell, men inget av de undersökta läromedlen hade fullt stöd för alla fem praktikerna i modellen. I och med att de undersökta läromedlen varierade stort i vilket stöd de ger för läraren att orkestrera produktiva matematiska diskussioner, är en slutsats att alla har potential att stötta lärare, men läraren behöver kunna utläsa detta stöd för att antingen välja läromedel eller produktivt använda det läromedel som finns tillhands.
152

MÉTODOS DE PREDIÇÃO E ESTIMAÇÃO DE VALOR GENOTÍPICO E ESTRATIFICAÇÃO AMBIENTAL PARA AVALIAÇÃO E RECOMENDAÇÃO DE CULTIVARES / Breeding value prediction and estimation methods and environmental stratification for cultivar evaluation and recommendation.

FELIPE, Cristiane Rachel de Paiva 13 June 2008 (has links)
Made available in DSpace on 2014-07-29T14:52:09Z (GMT). No. of bitstreams: 1 tese cristiane.pdf: 805152 bytes, checksum: 17b10ac06483864b2875c174a70c8625 (MD5) Previous issue date: 2008-06-13 / This research had the objective of evaluating the effects of different statistical approaches for the selection and ranking of genotypes, in the context of maize varieties trials. For that, data from real trials designed in lattice were used, in the Goiás State, Brazil, in the growing seasons of 2002/2003, 2003/2004, 2004/2005 and 2005/2006, as well as data from simulated experiments, aiming to cover situations related to that reality. The study also intended to quantify the effects of the genotype by environment interactions (GxE) from the real trials, aiming for the environmental stratification for the maize cultivation in the State, pointing out the cultivar evaluation and recommendation. Considering those objectives, the study is divided in three scientific articles. In the first one (Chapter 3), the effects of approaches of fixed model (FF), mixed model with random effect of blocks (AF), mixed model with random effect of treatments (FA), random model (AA), and James-Stein s estimator (JS) were evaluated on the selection and ranking of genotypes tested on the maize varieties trials, coordinated by the Agência Goiana de Desenvolvimento Rural e Fundiário (AgenciaRural Goiás). The experiments, in number of 47, were installed in lattice design, with three replications, during the four cited harvest years. In the second article (Chapter 4), the same approaches were evaluated, in terms of accuracy, mean predictive deviation and precision of their estimates/predictions, considering the simulated trials, also in lattice. Forty-eight cases were considered, corresponding to the combinations of different experimental sizes (15, 54, 105, and 450 treatments), genotypic determination coefficients h2' (6%, 15%, 25%, 48%, 63% and 82%), and two probability distributions for the generation of genotypic effects (normal and uniform). One thousand trials were simulated for each case, reaching the total of 48,000 experiments. The third and last article (Chapter 5) refers to the study of the GxE interaction, emphasizing the already mentioned environmental stratification, where the winner genotypes approach in association with the AMMI analysis (additive main effects and multiplicative interaction model) was adopted. Among the results and conclusions achieved through this study, it is possible to point out: i) the adoption of statistical approaches with shrinkage effect on the genotypic means results in the selection of a lower number of genotypes, especially in those trials whose mean of the check cultivars (baseline to the genotypic selection) is higher than the experimental grand mean; this fact reduces the number of genotypes with low yield potential in the next cycles of the selection program; ii) the use of models with fixed effects of treatments leads to a higher percentage of selected genotypes, mainly in the experiments whose check varieties mean overcomes the experimental grand mean; iii) among the shrinkage statistic approaches evaluated, the AA model must be preferred for the selection of genotypes, due to its capacity for better predicting the parametric genotypic effects (higher accuracy and lower mean predictive deviation), no matter if these effects are normally or uniformly distributed; iv) on the other hand, the FF model shows the worst relative performance, except for the situations where the variability among the genetic treatments is high (h2 ®1,0); v) considering low values for h2 (6%), the FA model shows efficiency similar to the AA model; vi) two established environmental strata showed to be consistent throughout the years, even when the tested genotypes were altered from one harvest season to the other: Ipameri, Inhumas and Senador Canêdo (stable to four years), and Porangatu and Orizona (stable along three years); vii) considering the obtained clustering, it is possible to reduce, at least 16%, the number of test locations currently used, and/or substitute the redundant locations by test places which better represent the recommended target region, aiming to increase the evaluation efficiency of the GxE interaction, in the scope of the genetic plant breeding program; viii) the ALBandeirante variety presents high yield potential and adaptability to the maize cultivation conditions in the Goiás State. / This research had the objective of evaluating the effects of different statistical approaches for the selection and ranking of genotypes, in the context of maize varieties trials. For that, data from real trials designed in lattice were used, in the Goiás State, Brazil, in the growing seasons of 2002/2003, 2003/2004, 2004/2005 and 2005/2006, as well as data from simulated experiments, aiming to cover situations related to that reality. The study also intended to quantify the effects of the genotype by environment interactions (GxE) from the real trials, aiming for the environmental stratification for the maize cultivation in the State, pointing out the cultivar evaluation and recommendation. Considering those objectives, the study is divided in three scientific articles. In the first one (Chapter 3), the effects of approaches of fixed model (FF), mixed model with random effect of blocks (AF), mixed model with random effect of treatments (FA), random model (AA), and James-Stein s estimator (JS) were evaluated on the selection and ranking of genotypes tested on the maize varieties trials, coordinated by the Agência Goiana de Desenvolvimento Rural e Fundiário (AgenciaRural Goiás). The experiments, in number of 47, were installed in lattice design, with three replications, during the four cited harvest years. In the second article (Chapter 4), the same approaches were evaluated, in terms of accuracy, mean predictive deviation and precision of their estimates/predictions, considering the simulated trials, also in lattice. Forty-eight cases were considered, corresponding to the combinations of different experimental sizes (15, 54, 105, and 450 treatments), genotypic determination coefficients h2' (6%, 15%, 25%, 48%, 63% and 82%), and two probability distributions for the generation of genotypic effects (normal and uniform). One thousand trials were simulated for each case, reaching the total of 48,000 experiments. The third and last article (Chapter 5) refers to the study of the GxE interaction, emphasizing the already mentioned environmental stratification, where the winner genotypes approach in association with the AMMI analysis (additive main effects and multiplicative interaction model) was adopted. Among the results and conclusions achieved through this study, it is possible to point out: i) the adoption of statistical approaches with shrinkage effect on the genotypic means results in the selection of a lower number of genotypes, especially in those trials whose mean of the check cultivars (baseline to the genotypic selection) is higher than the experimental grand mean; this fact reduces the number of genotypes with low yield potential in the next cycles of the selection program; ii) the use of models with fixed effects of treatments leads to a higher percentage of selected genotypes, mainly in the experiments whose check varieties mean overcomes the experimental grand mean; iii) among the shrinkage statistic approaches evaluated, the AA model must be preferred for the selection of genotypes, due to its capacity for better predicting the parametric genotypic effects (higher accuracy and lower mean predictive deviation), no matter if these effects are normally or uniformly distributed; iv) on the other hand, the FF model shows the worst relative performance, except for the situations where the variability among the genetic treatments is high (h2 ®1,0); v) considering low values for h2 (6%), the FA model shows efficiency similar to the AA model; vi) two established environmental strata showed to be consistent throughout the years, even when the tested genotypes were altered from one harvest season to the other: Ipameri, Inhumas and Senador Canêdo (stable to four years), and Porangatu and Orizona (stable along three years); vii) considering the obtained clustering, it is possible to reduce, at least 16%, the number of test locations currently used, and/or substitute the redundant locations by test places which better represent the recommended target region, aiming to increase the evaluation efficiency of the GxE interaction, in the scope of the genetic plant breeding program; viii) the ALBandeirante variety presents high yield potential and adaptability to the maize cultivation conditions in the Goiás State. / O presente trabalho teve como objetivo avaliar diferentes abordagens estatísticas em relação à seleção e ordenação de genótipos, no contexto de ensaios varietais de milho. Para isso, utilizaram-se dados reais de ensaios delineados em látice, conduzidos no Estado de Goiás, nas safras 2002/2003, 2003/2004, 2004/2005 e 2005/2006, bem como dados de experimentos simulados, nos quais se buscaram cobrir situações similares a essa realidade. O estudo propôs-se, ainda, a quantificar os efeitos da interação de genótipos com ambientes (GxE), a partir dos ensaios reais, visando-se à estratificação ambiental para a cultura do milho no Estado, com ênfase na avaliação e recomendação de cultivares. A partir desses objetivos, o trabalho apresenta-se estruturado na forma de três artigos científicos. No primeiro deles (Capítulo 3), avaliaram-se os efeitos das abordagens de modelo fixo (FF), modelo misto com efeito aleatório de blocos (AF), modelo misto com efeito aleatório de tratamentos (FA), modelo aleatório (AA) e do estimador de James-Stein (JS), na seleção e ordenação de genótipos testados na rede dos ensaios de variedades de milho, coordenada pela Agência Goiana de Desenvolvimento Rural e Fundiário (AgenciaRural Goiás). Os experimentos, em número de 47, foram instalados em látice, com três repetições, tendo sido conduzidos durante os quatro anos agrícolas citados. No segundo artigo (Capítulo 4), as mesmas abordagens foram avaliadas em termos de acurácia, desvio preditivo médio e precisão de suas estimativas/predições, considerando-se os experimentos simulados, também em látice. Foram considerados 48 casos, correspondentes às combinações de diferentes tamanhos experimentais (15, 54, 105 e 450 tratamentos), coeficientes de determinação genotípica h2' (6%, 15%, 25%, 48%, 63% e 82%) e duas distribuições de probabilidade para a geração dos efeitos genotípicos (normal e uniforme). Foram gerados 1.000 ensaios para cada caso, totalizando 48.000 experimentos. O terceiro e último artigo (Capítulo 5) refere-se ao estudo da interação GxE, com ênfase na referida estratificação ambiental, para o qual se adotou a abordagem de genótipos vencedores, associada à análise AMMI (modelo de efeitos principais aditivos e interação multiplicativa). Entre os resultados e conclusões obtidos, destacam-se: i) a adoção de abordagens estatísticas que promovem shrinkage das médias genotípicas resultam na seleção de menor número de genótipos, especialmente quando à média das cultivares testemunhas (referência para a seleção genotípica), que é superior à média experimental, reduzindo o número de genótipos pouco produtivos nos ciclos seguintes do programa de seleção; ii) o uso de modelos com efeitos fixos de tratamentos leva a um maior percentual de seleção de genótipos, sobretudo nos experimentos cuja média das testemunhas supera a média experimental; iii) entre as abordagens estatísticas shrinkage avaliadas, o modelo AA deve ser preferido para a seleção de genótipos, em razão de sua melhor capacidade de predição dos efeitos genotípicos paramétricos (maior acurácia e menor desvio preditivo médio), independentemente de esses efeitos terem distribuição normal ou uniforme; iv) contrariamente, o modelo FF demonstra o pior desempenho relativo, excetuando-se as situações em que a variabilidade entre os tratamentos genéticos é elevada (h2 ®1,0); v) sob baixos valores de h2 (6%), o modelo FA apresenta eficiência similar ao modelo AA; vi) dois estratos ambientais estabelecidos mostraram-se consistentes, ao longo dos anos, mesmo alterando-se os genótipos testados de uma safra agrícola para a outra: Ipameri, Inhumas e Senador Canêdo, (estável em quatro anos), e Porangatu e Orizona (estável em três anos); vii) com os agrupamentos obtidos é possível reduzir, pelo menos 16%, o número de locais de teste atualmente utilizados e, ou, efetuar a substituição de locais redundantes por outros pontos de teste que melhor representem a região alvo da recomendação, de modo a aumentar a eficiência da avaliação da interação GxE, no âmbito do programa de melhoramento; viii) a variedade ALBandeirante apresenta alto potencial produtivo e grande adaptabilidade às condições de cultivo do milho no Estado de Goiás. / O presente trabalho teve como objetivo avaliar diferentes abordagens estatísticas em relação à seleção e ordenação de genótipos, no contexto de ensaios varietais de milho. Para isso, utilizaram-se dados reais de ensaios delineados em látice, conduzidos no Estado de Goiás, nas safras 2002/2003, 2003/2004, 2004/2005 e 2005/2006, bem como dados de experimentos simulados, nos quais se buscaram cobrir situações similares a essa realidade. O estudo propôs-se, ainda, a quantificar os efeitos da interação de genótipos com ambientes (GxE), a partir dos ensaios reais, visando-se à estratificação ambiental para a cultura do milho no Estado, com ênfase na avaliação e recomendação de cultivares. A partir desses objetivos, o trabalho apresenta-se estruturado na forma de três artigos científicos. No primeiro deles (Capítulo 3), avaliaram-se os efeitos das abordagens de modelo fixo (FF), modelo misto com efeito aleatório de blocos (AF), modelo misto com efeito aleatório de tratamentos (FA), modelo aleatório (AA) e do estimador de James-Stein (JS), na seleção e ordenação de genótipos testados na rede dos ensaios de variedades de milho, coordenada pela Agência Goiana de Desenvolvimento Rural e Fundiário (AgenciaRural Goiás). Os experimentos, em número de 47, foram instalados em látice, com três repetições, tendo sido conduzidos durante os quatro anos agrícolas citados. No segundo artigo (Capítulo 4), as mesmas abordagens foram avaliadas em termos de acurácia, desvio preditivo médio e precisão de suas estimativas/predições, considerando-se os experimentos simulados, também em látice. Foram considerados 48 casos, correspondentes às combinações de diferentes tamanhos experimentais (15, 54, 105 e 450 tratamentos), coeficientes de determinação genotípica h2' (6%, 15%, 25%, 48%, 63% e 82%) e duas distribuições de probabilidade para a geração dos efeitos genotípicos (normal e uniforme). Foram gerados 1.000 ensaios para cada caso, totalizando 48.000 experimentos. O terceiro e último artigo (Capítulo 5) refere-se ao estudo da interação GxE, com ênfase na referida estratificação ambiental, para o qual se adotou a abordagem de genótipos vencedores, associada à análise AMMI (modelo de efeitos principais aditivos e interação multiplicativa). Entre os resultados e conclusões obtidos, destacam-se: i) a adoção de abordagens estatísticas que promovem shrinkage das médias genotípicas resultam na seleção de menor número de genótipos, especialmente quando à média das cultivares testemunhas (referência para a seleção genotípica), que é superior à média experimental, reduzindo o número de genótipos pouco produtivos nos ciclos seguintes do programa de seleção; ii) o uso de modelos com efeitos fixos de tratamentos leva a um maior percentual de seleção de genótipos, sobretudo nos experimentos cuja média das testemunhas supera a média experimental; iii) entre as abordagens estatísticas shrinkage avaliadas, o modelo AA deve ser preferido para a seleção de genótipos, em razão de sua melhor capacidade de predição dos efeitos genotípicos paramétricos (maior acurácia e menor desvio preditivo médio), independentemente de esses efeitos terem distribuição normal ou uniforme; iv) contrariamente, o modelo FF demonstra o pior desempenho relativo, excetuando-se as situações em que a variabilidade entre os tratamentos genéticos é elevada (h2 ®1,0); v) sob baixos valores de h2 (6%), o modelo FA apresenta eficiência similar ao modelo AA; vi) dois estratos ambientais estabelecidos mostraram-se consistentes, ao longo dos anos, mesmo alterando-se os genótipos testados de uma safra agrícola para a outra: Ipameri, Inhumas e Senador Canêdo, (estável em quatro anos), e Porangatu e Orizona (estável em três anos); vii) com os agrupamentos obtidos é possível reduzir, pelo menos 16%, o número de locais de teste atualmente utilizados e, ou, efetuar a substituição de locais redundantes por outros pontos de teste que melhor representem a região alvo da recomendação, de modo a aumentar a eficiência da avaliação da interação GxE, no âmbito do programa de melhoramento; viii) a variedade ALBandeirante apresenta alto potencial produtivo e grande adaptabilidade às condições de cultivo do milho no Estado de Goiás.
153

Hypersurfaces Levi-plates et leur complément dans les surfaces complexes / Levi-flat hypersurfaces and their complement in complex surfaces

Canales Gonzalez, Carolina 14 December 2015 (has links)
Dans ce mémoire nous étudions les hypersurfaces Levi-plates analytiques dans les surfaces algébriques complexes. Il s'agit des hypersurfaces réelles qui admettent un feuilletage par des courbes holomorphes, appelé le feuilletage de Cauchy Riemann (CR). Dans un premier temps nous montrons que si ce dernier admet une dynamique chaotique (i.e. s'il n'admet pas de mesure transverse invariante) alors les composantes connexes de l'extérieur de l'hypersurface sont des modifications de domaines de Stein. Ceci permet d'étendre le feuilletage CR en un feuilletage algébrique singulier sur la surface complexe ambiante. Nous appliquons ce résultat pour montrer, par l'absurde, qu'une hypersurface Levi-plate analytique qui admet une structure affine transverse dans une surface algébrique complexe possède une mesure transverse invariante. Ceci nous amène à conjecturer que les hypersurfaces Levi-plates dans les surfaces algébriques complexes qui sont difféomorphes à un fibré hyperbolique en tores sur le cercle sont des fibrations par courbes algébriques. / In this work we study analytic Levi-flat hypersurfaces in complex algebraic surfaces. These are real hypersurfaces that admit a foliation by holomorphic curves, called Cauchy Riemann foliation (CR). First, we show that if this foliation admits chaotic dynamics (i.e. if it doesn't admit an invariant transverse measure), then the connected components of the complement of the hypersurface are Stein. This allows us to extend the CR foliation to a singular algebraic foliation on the ambient complex surface. We apply this result to prove, by contradiction, that analytic Levi-flat hypersurfaces admitting a transverse affine structure in a complex algebraic surface have a transverse invariant measure. This leads us to conjecture that Levi-flat hypersurfaces in complex algebraic surfaces that are diffeomorphic to a hyperbolic tori bundle over the circle are fibrations by algebraic curves.
154

Estimation d'une matrice d'échelle. / Scale matrix estimation

Haddouche, Mohamed Anis 31 October 2019 (has links)
Beaucoup de résultats sur l’estimation d’une matrice d’échelle en analyse multidimensionnelle sont obtenus sous l’hypothèse de normalité (condition sous laquelle il s’agit de la matrice de covariance). Or il s’avère que, dans des domaines tels que la gestion de portefeuille en finance, cette hypothèse n’est pas très appropriée. Dans ce cas, la famille des distributions à symétrie elliptique, qui contient la distribution gaussienne, est une alternative intéressante. Nous considérons dans cette thèse le problème d’estimation de la matrice d’échelle Σ du modèle additif Yp_m = M + E, d’un point de vue de la théorie de la décision. Ici, p représente le nombre de variables, m le nombre d’observations, M une matrice de paramètres inconnus de rang q < p et E un bruit aléatoire de distribution à symétrie elliptique, avec une matrice de covariance proportionnelle à Im x Σ. Ce problème d’estimation est abordé sous la représentation canonique de ce modèle où la matrice d’observation Y est décomposée en deux matrices, à savoir, Zq x p qui résume l’information contenue dans M et une matrice Un x p, où n = m - q, qui résume l’information suffisante pour l’estimation de Σ. Comme les estimateurs naturels de la forme Σa = a S (où S = UT U et a est une constante positive) ne sont pas de bons estimateurs lorsque le nombre de variables p et le rapport p=n sont grands, nous proposons des estimateurs alternatifs de la forme ^Σa;G = a(S + S S+G(Z; S)) où S+ est l’inverse de Moore-Penrose de S (qui coïncide avec l’inverse S-1 lorsque S est inversible). Nous fournissons des conditions sur la matrice de correction SS+G(Z; S) telles que ^Σa;G améliore^Σa sous le coût quadratique L(Σ; ^Σ) = tr(^ΣΣ‾1 - Ip)² et sous une modification de ce dernier, à savoir le coût basé sur les données LS (Σ; ^Σ) = tr(S+Σ(^ΣΣ‾1 - Ip)²). Nous adoptons une approche unifiée des deux cas où S est inversible et S est non inversible. À cette fin, une nouvelle identité de type Stein-Haff et un nouveau calcul sur la décomposition en valeurs propres de S sont développés. Notre théorie est illustrée par une grande classe d’estimateurs orthogonalement invariants et par un ensemble de simulations. / Numerous results on the estimation of a scale matrix in multivariate analysis are obtained under Gaussian assumption (condition under which it is the covariance matrix). However in such areas as Portfolio management in finance, this assumption is not well adapted. Thus, the family of elliptical symmetric distribution, which contains the Gaussian distribution, is an interesting alternative. In this thesis, we consider the problem of estimating the scale matrix _ of the additif model Yp_m = M + E, under theoretical decision point of view. Here, p is the number of variables, m is the number of observations, M is a matrix of unknown parameters with rank q < p and E is a random noise, whose distribution is elliptically symmetric with covariance matrix proportional to Im x Σ. It is more convenient to deal with the canonical forme of this model where Y is decomposed in two matrices, namely, Zq_p which summarizes the information contained in M, and Un_p, where n = m - q which summarizes the information sufficient to estimate Σ. As the natural estimators of the form ^Σ a = a S (where S = UT U and a is a positive constant) perform poorly when the dimension of variables p and the ratio p=n are large, we propose estimators of the form ^Σa;G = a(S + S S+G(Z; S)) where S+ is the Moore-Penrose inverse of S (which coincides with S-1 when S is invertible). We provide conditions on the correction matrix SS+G(Z; S) such that ^Σa;G improves over ^Σa under the quadratic loss L(Σ; ^Σ) = tr(^ΣΣ‾1 - Ip)² and under the data based loss LS (Σ; ^Σ) = tr(S+Σ(^ΣΣ‾1 - Ip)²).. We adopt a unified approach of the two cases where S is invertible and S is non-invertible. To this end, a new Stein-Haff type identity and calculus on eigenstructure for S are developed. Our theory is illustrated with the large class of orthogonally invariant estimators and with simulations.
155

The Origins of Professorship in the American Clarinet School and the Lasting Influence of Stein, Stubbins, and Voxman

McCall, Jenna Abdelhadi 12 1900 (has links)
The American Clarinet School includes approaches to clarinet playing from European immigrants who instilled their musical style and ideas in the first generation of American-born clarinetists. Some of the first influential pedagogues from Europe include Daniel Bonade (1896-1976), Gustave Langenus (1883-1957), Gaston Hamelin (1884-1951), and Simeon Bellison (1881-1953). Even though they inspired many ideas of the American approach to clarinet, they were known in their time as performers rather than teachers first. The aim of this dissertation is to provide further examination into the modern clarinet professorship in the United States by examining three of the first generation of American-born clarinet professors and their contributions to pedagogy: Keith Stein (1908-1980), William Stubbins (1911-1975), and Himie Voxman (1912-2011). Topics discussed include embouchure, hand position, articulation, technique, expression and phrasing, equipment, teaching beginners, and repertoire.
156

[en] AN INVITATION TO NOISE SENSITIVITY AND APPLICATIONS TO QUENCHED VORONOI PERCOLATION / [pt] UM CONVITE À SENSIBILIDADE A RUÍDO E APLICAÇÕES PARA PERCOLAÇÃO DE VORONOI DO TIPO QUENCHED

DANIEL DE LA RIVA MASSAAD 25 September 2020 (has links)
[pt] Nós começamos essa dissertação com um panorama geral e introdutório dos tópicos de Sensibilidade a Ruído e Percolação . Como essas áreas podem ser desconhecidas por muitos estudantes de pós-graduação, nós apresentamos o material de uma maneira acessível, com o intuito de divulgar importantes técnicas e resultados dessas áreas. Nós também vamos introduzir o modelo para Percolação de Voronoi e apresentar resultados sobre probabilidades de cruzamentos neste modelo. Nos últimos dois capulos nós iremos considerar Sensibilidade a Ruído para Percolação do tipo quenched. Em particular, no penúltimo capítulo nós vamos apresentar resultados do artigo Quenched Voronoi Percolation de Daniel Ahlberg, Simon Griffiths, Robert Morris e Vincent Tassion, e no último capítulo provaremos um teorema que melhora uma das cotas deste artigo. / [en] We begin this dissertation by giving an introductory overview of the topics of Noise Sensitivity and Percolation. As these areas may be unfamiliar to many graduate students, we present the material in an accessible way, with the objective of publicising important techniques and results in these areas.We shall also introduce the model of Voronoi Percolation and present results of Vincent Tassion on crossing probabilities in this model. In the last two chapters we consider Noise Sensitivity of Quenched Voronoi Percolation. In particular, in the penultimate chapter we present the results of the paper Quenched Voronoi Percolation by Daniel Ahlberg, Simon Griffiths, Robert Morris and Vincent Tassion, and in the final chapter we prove a theorem which improves one of the bounds of that paper.
157

Public Negotiation: Magazine Culture and Female Authorship, 1900-1930

Weaver, Angela L. 07 December 2009 (has links)
No description available.
158

Modernism and the queer : Djuna Barnes/Gertrude Stein

Shin, Ery January 2013 (has links)
Djuna Barnes and Gertrude Stein may appear unrelated to one another at first glance. We have an impoverished upstate New Yorker versus relatively comfortable Californian, bisexual romantic nomad versus lesbian monogamist, nihilist versus life-affirming enthusiast, and agnostic-atheist versus secular Jew. When they are referenced together (which happens rarely), it is usually in the context of their Parisian exploits. But a closer look reveals more vital affinities. Both writers remain problematically situated in the modernist canon. Both were inspired by visual art. Both struggled to get published during their lifetimes. Both disassociated themselves from mainstream feminist movements, preferring subtler, more idiosyncratic ways of questioning the status quo. Both held a sustained interest in the queer and, as this dissertation seeks to demonstrate, imagined that theme in original ways—Barnes, through loss; Stein, through phenomenology. Writing out of the spirit of Christian martyrdom, Barnes revels in queer suffering and its transfiguring potential: queers extravagantly lose (themselves), fail, and suffer, yet such ordeals aren’t without value. The first half of my dissertation, thus, appraises Barnes’ “queer negativity” in general before pondering how its masochistic energies push against those authorities that would negate the queer. Chapter One analyzes Barnes’ mythical-seeming transgendered figures who encounter profound failure, despite the imaginative freedom emanating from their ahistorical surroundings. Barnes’ sense of queer failure intensifies in Chapter Two, where same-sex desire invokes the abject by symbolically collapsing psychic boundaries between lovers and refusing reproductive futurity. Both chapters contextualize the moral inversion that becomes the focus of Chapter Three: how does such nihilism tragically ennoble the queer and endow it with insurgent impulses? Without taking a self-consciously queer activist stance, Barnes draws on what Gilles Deleuze would later enunciate as an inverted affect regime: the power of punishment to enforce repressive sexual regulations through pain and hence to bridle perversion becomes inverted when punishment opens the portal to pleasure, when pleasure relocates to sites of perversion. If Barnes writes as a romantic martyr, Stein looks at the queer through a phenomenologist’s eyes. The reciprocity between social conditioning and consciousness, in particular, remains an urgent concern throughout her career. To be “queer,” one often breaks away from a lifetime of habituated orientations toward sex and gender. But queerness cannot wholly bracket the norms that have been left behind. It exists in relation to what it queers. Foregrounding this discussion, Chapter Four examines how Stein’s modernism, phenomenology, and queer criticism intersect. Chapter Five investigates how “Miss Furr and Miss Skeene,” “Many Many Women,” and The Making of Americans reorient us from the “straight” and narrow. Yet this reorientation remains partial. Not all heteronormative biases can be shed, as is evident in The Making of Americans’ classist undertones running through its “singular” queer vision. The sixth chapter further tests the limits of reorientation as such. Ida’s Ida desperately wants to live a queer life, but discovers that she cannot if she approaches queerness as a radically separatist ideal. A solipsistic universe where she can entirely withdraw from society through sleep, silence, or soliloquy remains a fantasy. Ida’s internal conflict, in turn, mirrors Stein’s struggle to enact aesthetic modes that prove just as impossible to practice, being devoted to eliminating memory, emotions, personal identity, and social awareness.
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Analyse harmonique associée à des systèmes de racines et aux opérateurs de Dunkl rationnels

Deleaval, Luc 07 December 2010 (has links) (PDF)
Dans cette thèse, on s'intéresse à l'analyse harmonique et aux fonctions spéciales associées aux opérateurs de Dunkl rationnels qui sont des déformations des dérivées directionnelles par des réflexions. Ils fournissent un outil décisif pour étendre, dans le cadre des systèmes de racines et des groupes de réflexions associés, l'analyse de Fourier euclidienne et l'analyse sur les espaces symétriques riemanniens plats. Après avoir donné un panorama détaillé de la théorie de Dunkl, on étudie l'opérateur maximal défini dans ce contexte. On commence par apporter des améliorations sur le comportement des constantes du théorème maximal de Thangavelu et Xu pour un groupe de réflexions quelconque. On étend ensuite dans un cadre vectoriel leur théorème en établissant dans le cas Z_2^d des inégalités de Fefferman-Stein. Pour y parvenir et puisque les techniques d'analyse réelle ne se prêtent pas à cet opérateur maximal, on construit un opérateur de type Hardy-Littlewood plus commode à étudier. A cet effet, on donne une estimation fine de la translation généralisée de l'indicatrice d'une boule. Notre étude est ensuite consacrée à des résultats d'intégrabilité exponentielle qui complètent les inégalités de Fefferman-Stein, et à un théorème maximal vectoriel pour des hypergroupes de Bessel-Kingman. Enfin, on développe l'analyse de Dunkl dans le cas d'un sous-système positif de racines orthogonales. On y établit une formule explicite du noyau de Dunkl et une formule produit qui implique le caractère borné de la translation de Dunkl. Le cas particulier d'un système de type A_1 est étudié afin d'établir une égalité liant les fonctions de Bessel normalisées et les polynômes de Gegenbauer.
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JSWT+估計應用於線性迴歸變數選取之研究 / Variable Selection Based on JSWT+ Estimator for Linear Regression

王政忠, Wang,Jheng-Jhong Unknown Date (has links)
變數選取方法已經成為各領域在處理多維度資料的工具。Zhou與Hwang在2005年,為了改善James-Stein positive part估計量(JS+)只能在完全模型(full model)與原始模型(origin model)兩者去做挑選,建立了具有Minimax性質同時加上門檻值的估計量,即James-Stein with Threshoding positive part估計量(JSWT+)。由於JSWT+估計量具有門檻值,使得此估計量可以在完全模型與其線性子集下做變數選取。我們想進一步了解如果將JSWT+估計量應用於線性迴歸分析時,藉由JSWT+估計具有門檻值的性質去做變數選取的效果如何?本文目的即是利用JSWT+估計量具有門檻值的性質,建立JSWT+估計量應用於線性迴歸模型變數挑選的流程。建立模擬資料分析,以可同時做係數壓縮及變數選取的LASSO方法與我們所提出JSWT+變數選取的流程去比較係數路徑及變數選取時差異比較,最後將我們提出JSWT+變數選取的流程對實際資料攝護腺癌資料(Tibshirani,1996)做變數挑選。則當考慮解釋變數個數小於樣本個數情況下,JSWT+與LASSO在變數選取的比較結果顯示,JSWT+表現的比較好,且可直接得到估計量的理想參數。

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