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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.
231

Atributos ecofisiológicos do híbrido DKB-390 e modelo estocástico para previsão da produtividade de grãos / Ecophysiological attributes of hybrid DKB-390 and sthocastic model for predicting grain productivity

Euro Roberto Detomini 02 April 2008 (has links)
O milho é uma das culturas mais importantes do mundo, pois os produtos dele oriundos são largamente utilizados na indústria de amidos, na alimentação animal e humana, e também na produção de energia proveniente de biomassa. Por esse motivo, há sempre um grande interesse em conhecer a potencialidade de uso dos principais materiais genéticos disponíveis em relação aos ambientes em que serão inseridos. Este trabalho teve como objetivo central caracterizar, para o genótipo DKB-390 conduzido sob condição irrigada, atributos ecofisiológicos como área foliar, eficiência de uso da radiação, coeficiente de extinção, coeficientes de cultura, consumo hídrico e componentes de espiga; bem como conceitualizar modelos norteadores de manejo e de planejamento para cultura do milho, no intuito de obter a produtividade de grãos contemplada pelas incertezas climáticas diárias dos principais elementos do clima e suas correlações, para posteriormente se obter as correspondentes necessidades de água e de nitrogênio pela cultura. Para tanto, um experimento de campo foi conduzido, informações da literatura foram revisadas e levantadas, e modelos de previsão foram concebidos para a produtividade de grãos e para as demais variáveis de interesse. Como principais resultados, obteve-se: (i) sob condições adequadas de suprimento hídrico e de nitrogênio, o híbrido DKB-390 requer cerca de 573 litros de água para kg de grão que produz; (ii) o genótipo responde significativamente à segunda cobertura com nitrogênio, caso a cultura seja conduzida sob elevada população de plantas e adequado suprimento hídrico; (iii) a segunda cobertura com nitrogênio promoveu melhor manutenção da área foliar durante a fase de enchimento de grãos; (iv) o incremento da segunda cobertura de nitrogênio promoveu maior eficiência de uso da água pela cultura, bem como um leve aumento nos valores modais do número de grãos por fileira (da espiga) e da massa de 1000 grãos; (v) sob condições de adequado suprimento hídrico, o coeficiente de extinção médio, generalizado para todo o ciclo, é da ordem de 0,4267; valor que tende a ser maior na medida em que o suprimento de nitrogênio é menor; (vi) a eficiência de uso da radiação foi calculada em 3,52 g (fitomassa seca de parte aérea) MJ-1 (radiação solar fotossinteticamente ativa interceptada), tendo sido menor em função do emprego do regime de nitrogênio mais restritivo; (vii) os coeficientes de cultura obtidos do experimento podem ser utilizados para o manejo da irrigação do híbrido DKB-390, para os principais subperíodos, para que a produtividade não seja penalizada por déficit hídrico; (viii) o índice de colheita (expresso em relação à parte aérea) foi da ordem de 40% (variando entre 37% e 43%) sob condições de suprimento adequado de água e nitrogênio, valores que tenderam a ser maiores quando da restrição da segunda cobertura; (ix) o modelo determinístico proposto simulou adequadamente a evolução da produtividade de fitomassa de parte aérea do híbrido empregado, bem como sua produtividade de grãos sob adequadas condições de suprimento hídrico e de nitrogênio; (x) o modelo determinístico simulou adequadamente as evapotranspirações diárias o consumo hídrico através do método de Penman-Monteith; (xi) o modelo estocástico sugerido mostrou-se satisfatório, mediante o uso da distribuição normal bivariada das variáveis radiação solar e temperatura média do ar, para simular a produtividade de grãos sob condições de suprimento hídrico adequado e sob déficit moderado; e (xii) aparentemente, o modelo estocástico necessita ser melhorado quanto à capacidade de previsão das necessidades hídricas e de nitrogênio, pois tende claramente a subestimar as primeiras e superestimar as segundas. / Maize is on of the world most important crops, given that the products generated from this cereal are largely used by sectors like starch industry, animal and human nutrition, as well as biomass energy production and refineries. For these reasons, there is frequently a huge interest in knowing the potential adoption of the main available genotypes in relation to the environment in which they will be supposedly subjected. Considering the hybrid DKB-390 under full irrigated conditions, this work has as the central objective to characterize the most important ecophysiological attributes such as leaf area, radiation use efficiency, extinction coefficient, crop coefficients, water use and ear yield components. Additionaly, specif goals were to conceptualize models applicable for both management and planning of maize crops in order to predict the grain productivity contemplated by daily climate incertainties of the driven climate variables (i.e. radiation and temperature) and their correlation, then to achieve the water and nitrogen requirement corresponding to the predicted productivity. A field experiment was carried out, useful information from literature were obtained and reviewed, and models were created towards to support the prediction tools. The following outcomes might be highligthed: (i) under suitable conditions of both nitrogen and water supply, hybrid DKB-390 requires about 573 litters of water per each kilogram of produced grain; (ii) the genotype is significantly responsive to the second nitrogen covering when growing under high plant population and suitable water supply; (iii) the second nitrogen covering has enhanced better leaf area maintainance during grain filling stage; (iv) the second nitrogen covering has led to a better water use efficiency, as well as slightly increased modal values of the number of kernels per row (of ear) and the mass of a thousand kernels; (v) under suitable water supply, averaged extinction coefficient might be generalized as 0.4267 throughout the whole cycle, whereas tending to be higher as the nitrogen supply is restricted; (vi) the radiation use efficiency as calculated as 3.52 g (above-ground dry matter) MJ-1 (intercepted photossyntheticaly active radiation), being smaller as the nitrogen supply is restricted; (vii) some crop coefficients were found for the main phenological stages and may be adopted for irrigation management of hybrid DKB-390, when one aims to not deplet the productivity; (viii) the harvest index (above-ground based) was found about 40% (varying from 37% to 43%) if water and nitrogen are added sufficiently, and is likely to be higher provided that the second covering is not done; (ix) the proposed determinist model has performed well when simulating above-ground dry matter time course and its corresponding grain productivity under full and moderated water deficit conditions; (x) by using Penman-Montheit method, the deterministic model apparently simulates well both daily evapotranspiration and water uses; (xi) through bivariate normal distribution of averaged daily solar radiation and air temperature, the suggested stochastic model has simulated grain productivity in a satisfactory way; and (xii) the suggested stochastic model need to be improved in terms of its water and nitrogen requirement predictability, given that it clearly tends to underestimate the former and overestimate the latter.
232

Modelo para estimação da produtividade de grãos de milho no estado de São Paulo. / Model to estimate corn yield at São Paulo state, Brazil.

Luis Gonzaga Medeiros de Figueredo Júnior 26 March 2004 (has links)
O presente trabalho tem por objetivo propor um modelo para estimação da produtividade de grãos de milho para o Estado de São Paulo com base nos valores mensais de temperatura, radiação solar e chuva, no intuito de disponibilizar ferramenta para o planejamento regional (identificação das épocas do ano e dos locais mais indicados para o cultivo de milho). O uso de modelos de crescimento e desenvolvimento vegetal possibilita uma economia de tempo, trabalho e quantidade de recursos para tomada de decisões referentes ao manejo no setor agrícola por possibilitar uma previsão do processo de interesse e/ou um melhor entendimento do sistema em estudo. O conhecimento da quantidade de energia solar disponível às plantas, bem como da capacidade de conversão da mesma em energia química metabólica, possibilita prever produtividade de grãos, no caso do milho, quanto à eficiência de conversão em biomassa, através de um modelo geral mecanístico, levando em consideração aspectos agrometeorológicos, fisiológicos, genéticos e edáficos. A assimilação de CO2 pode ser convertida em massa de carboidrato, produzida durante o processo de fotossíntese, em função do índice de área foliar, temperatura e radiação solar absorvida. Estimando-se os valores de radiação solar absorvida, fotoperíodo, índice de área foliar e duração do ciclo, considerando as correções quanto à respiração de manutenção e crescimento, bem como a variação temporal da área foliar, pode-se transformar esse valor em massa líquida de carboidrato total final produzida durante o ciclo. O balanço hídrico foi utilizado com a finalidade de estimar a deficiência hídrica durante o ciclo da cultura de milho, sendo adotado o método de Thornthwaite & Mather (1955), sendo a evapotranspiração de referência estimada pelo método de Thornthwaite (1948). A produtividade deplecionada de grãos de milho foi estimada a partir dos dados de produtividade potencial predita pelo modelo, considerando-se a depleção em função da evapotranspiração relativa (relação entre evapotranspiração real e evapotranspiração da cultura). A partir de dados climáticos obtidos de estações e postos meteorológicos localizados em diversas partes do estado de São Paulo, foram elaborados mapas de superfície no programa TNTmips, com a identificação, por município, das localidades com potencial para o desenvolvimento da cultura de milho. Através destes mapas, é possível identificar restrições quanto à deficiência hídrica, temperatura, radiação solar, produtividade potencial e produtividade de grãos de milho no estado de São Paulo. / The present work has the objective to suggest a model to estimate potential yield and corn yield for São Paulo state based on monthly values of temperature, solar radiation and rainfall, in order to dispose a tool for regional planning (identification of sites and timing during the year more indicated for maize cropping). The use of growing and development models allows savings in time, work and resources needed for making decisions regarding agricultural management, by enabling a preview of the process of interest and/or a better understanding of the system being studied. The knowledge of the available amount of solar energy to plants and the capability of those to convert it into metabolic chemical energy, allows to preview grain yield, in the case of corn, regarding to biomass converting efficiency, through a general mechanistic model, considering agro-meteorological, physiological, genetical and edaphological aspects. The carbon dioxide (CO2) assimilation can be converted into mass of carbohydrates produced during photosynthesis process, as a function of leaf area index, air temperature and absorbed solar radiation. By estimating the values of solar radiation, the photoperiod, the leaf area index, and the cycle length, and considering the corrections related to growing and maintenance respiration, as well as the temporal variation of leaf area, it is possible to transform those value into final net mass of total carbohydrate produced during the cycle. The hydric balance, as proposed by Thornthwaite & Mather (1955), was used with the objective to estimate the hydric deficit during maize cycle, being the reference evapotranspiration being estimated by Thornthwaite (1948). Corn yield was estimated up from potential yield predicted by the model, considering the depletion from the relative evapotranspiration (relation between real evapotranspiration and crop evapotranspiration). Starting from climatic data obtained from several meteorological station located at different sites in São Paulo State, Brazil, surface maps were elaborated using TNTmips software, with the identification, by county, of those sites with maize development potential. Through those maps it is possible to identify restriction regarding hydric deficit, temperature, solar radiation, potential yield, and corn yield in São Paulo State.
233

Aplicação de técnicas estatísticas multivariadas na avaliação de associações entre biomarcadores do estresse oxidativo e fatores dietéticos em indivíduos com dislipidemia controlada por estatinas / Application of multivariate statistical techniques to evaluate the association between biomarkers of the oxidative stress and dietetic factors in individuals with dyslipidemia controlled by statins

Patricia Borges Botelho 17 September 2009 (has links)
Estresse oxidativo é uma condição fisiológica que está associada à aterosclerose e pode ser influenciada pela dieta. Diante disso, o objetivo do presente estudo foi agrupar 57 indivíduos com dislipidemia controlada por estatinas, de acordo com quatro biomarcadores do estresse oxidativo, e avaliar diferenças quanto ao padrão dietético e ao perfil lipídico entre esses grupos. Para isso, amostras de sangue foram coletadas de 57 indivíduos com dislipidemia controlada por estatinas e os seguintes parâmetros foram avaliados: ingestão dietética por meio do registro alimentar de 6 dias, ácidos graxos plasmáticos, concentração de lipoproteínas, triglicerídeos, glicose, LDL oxidada (LDL(-)), malondialdeído (MDA) e atividade antioxidante total por DPPH (1,1-diphenyl-2-picrylhydrazyl) e FRAP (Ferric reducing power). Os indivíduos foram separados em cinco grupos pela análise de agrupamento. Todos os grupos apresentaram diferença com relação a pelo menos um dos biomarcadores do estresse oxidativo. A separação dos indivíduos na primeira componente baseou-se na atividade antioxidante total. Dessa forma, os clusters (grupos) localizados no quadrante direito caracterizaram-se por capacidade antioxidante total mais alta, bem como por maiores concentrações de ácido mirístico e menores de ácido araquidônico que os clusters (grupos) localizados no quadrante esquerdo. Uma correlação negativa foi observada entre DPPH e índice de peroxidabilidade. A segunda componente baseou-se nas diferenças no estado de oxidação determinado pelas concentrações de MDA e LDL(-). Os clusters (grupos) localizados no quadrante superior apresentaram estado oxidativo mais alto e menor concentração de HDL que os clusters (grupos) localizados no quadrante inferior. Nenhuma diferença foi observada quanto à ingestão dietética entre os cinco clusters (grupos). Portanto, supõe-se que a síntese de ácidos graxos e a concentração de HDL parecem exercer efeito mais expressivo que a ingestão dietética nas condições oxidativas dos indivíduos com dislipidemia controlada por estatinas. / Oxidative stress is a physiological condition that is associated with atherosclerosis, and it can be influenced by diet. Our objective was to group 57 individuals with dyslipidemia controlled by statins according to four oxidative biomarkers, and to evaluate the diet pattern and blood biochemistry differences between these groups. Blood samples were collected and the following parameters were evaluated: diet intake by 6-day dietary register, plasma fatty acids, lipoprotein concentration, glucose, oxidized low density lipoprotein (LDL(-)), malondialdehyde (MDA), and total antioxidant activity by DPPH (1,1-diphenyl-2-picrylhydrazyl) and FRAP (Ferric reducing power ) assays. Individuals were separated into five groups by cluster analysis. All groups showed a difference with respect to at least one of the four oxidative stress biomarkers. The separation of individuals in the first axis was based upon their total antioxidant activity. Clusters located on the right side showed higher total antioxidant activity, higher myristic fatty acid, and lower arachidonic fatty acid proportions than clusters located on the left side. A negative correlation was observed between DPPH and the peroxidability index. The second axis showed differences in oxidation status as measured by MDA and oxLDL concentrations. Clusters located on the upper side showed higher oxidative status and lower HDL cholesterol concentration than clusters located on the lower side. There were no differences in diet among the five clusters. Therefore, fatty acid synthesis and HDL cholesterol concentration seem to exert a more significant effect on the oxidative conditions of the individuals with dyslipidemia controlled by statins than does their food intake.
234

Etapas iniciais de aquisição lexical – habilidades estatísticas e simbólicas no tratamento de dependências não adjacentes

Laguardia, Milene Cristine de Castro Teixeira 03 November 2016 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-15T13:55:22Z No. of bitstreams: 1 milenecristinedecastroteixeiralaguardia.pdf: 2174544 bytes, checksum: 2efb54d1db55344c6cc5db2a04382473 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-17T15:59:07Z (GMT) No. of bitstreams: 1 milenecristinedecastroteixeiralaguardia.pdf: 2174544 bytes, checksum: 2efb54d1db55344c6cc5db2a04382473 (MD5) / Made available in DSpace on 2017-05-17T15:59:07Z (GMT). No. of bitstreams: 1 milenecristinedecastroteixeiralaguardia.pdf: 2174544 bytes, checksum: 2efb54d1db55344c6cc5db2a04382473 (MD5) Previous issue date: 2016-11-03 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este estudo diz respeito às etapas iniciais da aquisição lexical, focalizando a capacidade de o bebê identificar, abstrair e generalizar padrões de dependências não-adjacentes (DNAs) nos enunciados linguísticos e de usá-los na categorização inicial de elementos do léxico. Nossa tese é que o estabelecimento de relações entre elementos de DNAs é parte da etapa inicial de aquisição lexical e que, para tal estabelecimento, além de habilidades perceptuais, faz-se necessário o uso de habilidades computacionais – de manipulação de símbolos através de algoritmos – que torne possíveis (i) o reconhecimento e a identificação de elementos interrelacionados, que se apresentam em configuração de DNAs, e (ii) a abstração e generalização desses padrões a novos estímulos. DNAs são definidas como a co-ocorrência de marcadores morfossintáticos e/ou fonológicos, com material interveniente. Elegeram-se as DNAs como objeto de estudo por serem altamente frequentes nas línguas naturais e expressarem relações morfossintáticas (p.ex., concordância verbal, nominal de gênero e/ou de número etc.). Trabalhos com línguas artificiais (SAFFRAN et al 1996; GOMEZ et al. 2006; GOMEZ & MAYE, 2005; GOMEZ & LAKUSTA, 2004; LANGUS et al 2012 ; VAN DEN BOS et al 2012) sustentam que habilidades estatísticas e probabilísticas, de domínio geral, subjazem ao tratamento de DNAs por bebês e adultos. Nossa hipótese, em consonância com Marcus et al. (1999) e Peña et al. (2002), é que tais habilidades, sozinhas, não dão conta do tratamento de DNAs em língua natural e, portanto, bebês recorrem tanto a mecanismos gerais quanto a mecanismos computacionais/simbólicos, especificamente linguísticos, na aquisição de uma língua. Duas atividades experimentais foram desenvolvidas, com os seguintes objetivos específicos: (i) investigar se em ambiente prosódico determinado – alinhadas à fronteiras de sintagmas fonológicos – DNAs seriam mais facilmente percebidas por bebês do que em ambientes em que estão distantes de fronteiras fonológicas (Experimento 1 – participantes: bebês canadenses e bebês brasileiros, com média de idade de 11 meses); (ii) investigar se bebês são capazes de categorizar linguisticamente os elementos do léxico a partir do reconhecimento, abstração e generalização de DNAs (Experimento 2- participantes: bebês brasileiros, com média de idade de 11 meses). Nossos resultados são discutidos a partir de uma abordagem mista/integrada, que assume habilidades gerais e especificamente linguísticas no tratamento de enunciados pelo bebê durante o processo inicial de aquisição (GERVAIN & MEHLER, 2010; ENDRESS, NESPOR & MEHLER, 2009) e na hipótese do Bootstrapping prosódico (MORGAN & DEMUTH, 1996; CHRISTOPHE et al., 1997, 2008) e indicam que um ambiente prosódico específico (presença de fronteiras de sintagmas fonológicos) favorece o reconhecimento, abstração e generalização de DNAs e que estas favorecem a categorização inicial de itens do léxico. / This study investigates the initial stages of language acquisition by focusing on infant’s ability to identify, abstract and generalize non adjacent dependency (NAD) patterns in linguistic stimuli and also use them in initial word categorization. NAD is defined as the cooccurrence of morphosyntactic and/or phonological markers over one (or more) intervening element. Our thesis is that the identification of NAD relationships is part of initial lexical acquisition. Infants use perceptual and computational abilities in order to (i) recognize the related terms which appears in NAD configuration, and (ii) abstract and generalize these patterns to new stimuli. NAD was chosen as focus of this study since they are highly frequent elements in natural languages and they express morphosyntactic agreement ( verbal and noun ones). Research on NAD learning using artificial languages argue that statistical and probabilistic abilities, which belong to general cognitive domains, underlie the NAD treatment by infants and adults (SAFFRAN et al 1996; GOMEZ et al. 2006; GOMEZ & MAYE, 2005; GOMEZ & LAKUSTA, 2004; LANGUS et al 2012 ; VAN DEN BOS et al 2012). Our hypothesis, according to Marcus et al. (1999) e Peña et al. (2002), is that infants use as domain general mechanisms as well computational/symbolic, domain specific mechanisms are also necessary to NAD learning. Two experiments were conducted in order to: (i) explore if NAD in a specific prosodic context – aligned to phonological phrase boundary – are better perceived by 11-month-old infants than when they are far from a phonological phrase boundary (Experiment 1 – Canadian and Brazilian infants; (ii) to explore if 11-month-old infants can track and represent NAD at an abstract level and use them to categorize novel content words (Experiment 2 – Brazilian infants. Our results suggest that NAD aligned to prosodic phrase boundaries facilitate its recognition, abstraction and generalization and that abstract level representation of NAD promotes the initial word categorization. Taken together, our results are consistent with the prosodic bootstrapping hypothesis (MORGAN & DEMUTH, 1996; CHRISTOPHE et al., 1997, 2008) and lend support to an integrated approach with assumes that general and specific domain abilities are necessary for language acquisition (GERVAIN & MEHLER, 2010; ENDRESS, NESPOR & MEHLER, 2009).
235

Modelo de regressão Birnbaum-Saunders bivariado / Bivariate Birnbaum-Saunders regression model

Romeiro, Renata Guimarães, 1987- 24 August 2018 (has links)
Orientador: Filidor Edilfonso Vilca Labra / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação Científica / Made available in DSpace on 2018-08-24T16:29:00Z (GMT). No. of bitstreams: 1 Romeiro_RenataGuimaraes_M.pdf: 10761224 bytes, checksum: 3606332b6846c959d076e318f1667133 (MD5) Previous issue date: 2014 / Resumo: O modelo de regressão Birnbaum-Saunders de Rieck e Nedelman (1991) tem sido amplamente discutido por vários autores, com aplicações na área de sobrevivência e confiabilidade. Neste trabalho, desenvolvemos um modelo de regressão Birnbaum-Saunders bivariado através do uso da distribuição Senh-Normal proposta por Rieck (1989). Este modelo de regressão pode ser utilizado para analisar logaritmos de tempos de vida de duas unidades correlacionadas, e gera marginais correspondentes aos modelos de regressão Birnbaum-Saunders univariados. Apresentamos um estudo de inferência e análise de diagnóstico para modelo de regressão Birnbaum-Saunders bivariado proposto. Em primeiro lugar, apresentamos os estimadores obtidos através do método dos momentos e de máxima verossimilhança, e a matriz de informação observada de Fisher. Além disso, discutimos testes de hipóteses com base na normalidade assintótica dos estimadores de máxima verossimilhança. Em segundo lugar, desenvolvemos um método de diagnóstico para o modelo de regressão Birnbaum- Saunders bivariado baseado na metodologia de Cook (1986). Finalmente, apresentamos alguns resultados de estudos de simulações e aplicações em dados reais / Abstract: The Birnbaum-Saunders regression model of Rieck and Nedelman (1991) has been extensively discussed by various authors with application in survival and reliability studies. In this work a bivariate Birnbaum-Saunders regression model is developed through the use of Sinh-Normal distribution proposed by Rieck (1989). This bivariate regression model can be used to analyze correlated log-time of two units, it bivariate regression model has its marginal as the Birnbaum- Saunders regression model. For the bivariate Birnbaum-Saunders regression model is discussed some of its properties, in the moment estimation, the maximum likelihood estimation and the observed Fisher information matrix. Hypothesis testing is performed by using the asymptotic normality of the maximum-likelihood estimators. Influence diagnostic methods are developed for this model based on the Cook¿s(1986) approach. Finally, the results of a simulation study as well as an application to a real data set are presented / Mestrado / Estatistica / Mestra em Estatística
236

Problématiques statistiques rencontrées dans l’étude du traitement antirétroviral des adultes infectés par le VIH en Afrique subsaharienne / Statistical problems encountered in the study of antiretroviral treatment of adults infected with HIV in sub-Saharan Africa

Tchatchueng Mbougua, Jules Brice 12 June 2012 (has links)
Partant de problématiques statistiques rencontrées dans l'étude du traitement antirétroviral des adultes infectés par le virus de l'immunodéficience humaine (VIH) en Afrique subsaharienne, cette thèse cherche, d'une part, à favoriser la vulgarisation d'outils méthodologiques relativement récents auprès d'un public d'utilisateurs moins avertis et, d'autre part, à participer au développement de nouveaux outils. Le premier chapitre présente différentes méthodes de modélisation des données longitudinales dont des méthodes d'analyse de l'évolution d'un critère au cours du temps (les modèles linéaires mixtes généralisés et les modèles d'équations d'estimation généralisées) ou de la survenue d'un évènement au cours du temps (le modèle semi-paramétrique de Cox et ses extensions à la prise en compte des covariables dépendantes du temps et de la censure informative). Le deuxième chapitre s'intéresse aux tests de non-infériorité et propose deux développements de la procédure classique de ces tests pour les cas où la marge de non-infériorité est relative. Enfin, le troisième chapitre aborde la question des données manquantes et propose une extension de la méthode d'imputation multiple par les distributions conditionnelles univariées qui consiste à prendre en compte des effets non-linéaires des covariables dans les modèles d'imputation par des fonctions B-splines. Ces méthodes sont illustrées par des études sur le VIH au Cameroun et au Sénégal. / On the basis of statistical challenges encountered in study of antiretroviral treatment of adults infected with human immunodeficiency virus (HIV) in sub-Saharan Africa, this thesis aims to promote the dissemination of relatively recent methodological tools of less aware audience of users on one hand and to participate to development of new tools on the other hand. The first chapter presents various methods for modeling longitudinal data of which analysis methods for changing of a criterion over time (the generalized linear mixed models and models of generalized estimating equations) or the occurrence of an event over time (the semi-parametric Cox model and its extensions to take into account time-dependent covariates and informative censoring). The second chapter focuses on non-inferiority test and provides two developments of the classical procedure of these tests in cases where the non-inferiority margin is relative. The third chapter addresses the question of missing data and proposes an extension of the multiple imputation method based on fully conditional specification, to take into account nonlinear effects of covariates in the imputation models using B-splines functions. These methods are illustrated by studies on HIV in Cameroon and Senegal.
237

GESTÃO POR PROCESSOS E LEAN MANUFACTURING ASSOCIADA A CONTROLE ESTATÍSTICO DE PROCESSO ONLINE EM UMA INDÚSTRIA DE PRODUTOS EMPANADOS A BASE DE FRANGO / PROCESS MANAGEMENT AND LEAN MANUFACTURING ASSOCIATED WITH ONLINE STATSTIC PROCESS CONTROL IN A CHICKEN PRODUCTS INDUSTRY

Bocci, Gisele Santos 08 May 2007 (has links)
The objective of this work is to tell the application of the administration model for process management, Lean manufacturing and online statistical process in a industry of coated and formed chicken products, seeking to evaluate the acting of the processes key of the business continually with the customer's vision. The study was made by the evaluation of the process improvement, accomplished by control charts and capability indexes, comparing the data before and after the implantation of the administration system for process associated to the statistical process control. This way, the collected data suggest that the new administration model, brought for this company a larger involvement of all the members of the organization, in the search of the reduction of losses and products out of the technical specifications and mainly a larger attendance the customer s technical specification, however the causes of variation of the process need to be better investigated / O objetivo deste trabalho é desenvolver um sistema de gestão por processos e lean manufacturing associado ao controle estatístico de processo online em uma indústria de produtos empanados a base de frango, visando avaliar continuamente o desempenho dos processos chave do negócio com a visão do cliente. O estudo foi feito pela avaliação da melhoria do processo, realizado mediante gráficos de controle e índices de capabilidade, comparando os dados antes e após a implantação do sistema de gestão por processos e lean manufacturing associado ao controle estatístico de processo. Desta forma, os dados coletados sugeriram que o novo sistema de gestão, trouxe para essa empresa, um maior envolvimento de todos os integrantes da organização, na busca da redução de perdas e produtos fora das especificações técnicas e principalmente, um maior atendimento das necessidades dos clientes; porém as causas de variação do processo precisam ser melhores investigadas
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Využití data miningových metod při zpracování dat z demografických šetření / Using data mining methods for demographic survey data processing

Fišer, David January 2015 (has links)
USING DATA MINING METHODS FOR DEMOGRAPHIC SURVEY DATA PROCESSING Abstract The goal of the thesis was to describe and demonstrate principles of the process of knowledge discovery in databases - data mining (DM). In the theoretical part of the thesis, selected methods for data mining processes are described as well as basic principles of those DM techniques. In the second part of the thesis a DM task is realized in accordance to CRISP-DM methodology. Practical part of the thesis is divided into two parts and data from the survey of American Community Survey served as the basic data for the practical part of the thesis. First part contains a classification task which goal was to determinate whether the selected DM techniques can be used to solve missing data in the surveys. The success rate of classifications and following data value prediction in selected attributes was in 55-80 % range. The second part of the practical part of the thesis was then focused of determining knowledge of interest using associating rules and the GUHA method. Keywords: data mining, knowledge discovery in databases, statistic surveys, missing values, classification, association rules, GUHA method, ACS
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Systèmes d’Information Géographique et Lien Environnement – Santé (SIGLES) : contribution au développement d'outils cartographiques d'aide à la décision face aux risques sanitaires liés à l'environnement / Geographic Information Systems and Environmental Health

Occelli, Florent 24 September 2014 (has links)
La question des inégalités environnementales et sociales de santé (IESS) à l’échelle des territoires est rapportée à deux dimensions cumulatives : un niveau d’exposition des populations à un environnement de vie dégradé et un niveau de vulnérabilité face à ces facteurs de risques, capables d’affecter la santé. Ces travaux de recherche concernent les Systèmes d’Information Géographique (SIG) appliqués au domaine de la santé environnementale. Ils ont pour objectifs généraux la caractérisation de la qualité des milieux environnementaux et l’évaluation des IESS. L’atteinte de ces objectifs passe préalablement par la récolte, la genèse et la mise en forme de bases de données environnementales spatialisées. Ces bases issues de la surveillance physico-chimique et de la biosurveillance des milieux sont ensuite cartographiées à l'aide des outils SIG, notamment les méthodes géostatistiques d’interpolation spatiale. En parallèle, les disparités spatiales d'incidence de pathologies sont étudiées grâce à des méthodes de cartographie des maladies (Ratios d'Incidence Standardisés : SIR) et de détection de clusters atypiques d'évènements (statistique de scan) mises en œuvre sur la base de registres de maladies. Finalement des études écologiques spatialisées sont élaborées afin de rapprocher les cartographies environnementales générées aux indicateurs sanitaires et socio-économiques. Ces travaux s’attachent à répondre à la question « les populations présentant un état de santé dégradé vivent-elles dans un environnement dégradé ? » Ce questionnement a été étudié à travers trois axes de recherche. Le premier concerne la caractérisation de l’imprégnation de l’environnement par les éléments traces métalliques (ETM) et l’évaluation des IESS à fine résolution sur trois bassins de vie de la région Nord-Pas de Calais (NPdC). Cette recherche est menée à partir de mesures d’imprégnations biologiques réalisées à la fois chez des lichens épiphytes et chez l’Homme et d’un indicateur de défaveur localisé. Les ETM mesurés ont été considérés de manière individuelle, mais également de manière globale à travers le développement d’un indice intégré multimétallique, afin d’exprimer le niveau d’imprégnation général par plusieurs métaux. Des inégalités environnementales ont été mises en évidence à l’échelle des quartiers du bassin de Dunkerque. Nos résultats supposent également l’implication de l’environnement dans l’imprégnation des populations pour certains ETM.Dans le deuxième axe, nous avons mis en évidence des disparités spatiales d’incidence de l’insuffisance rénale chronique terminale entre les cantons du NPdC et souligné l’implication du statut socio-économique dans l’apparition de ces disparités, contrairement à d’autres facteurs (diabète, maladies cardiovasculaires, pratiques médicales). Seule une partie des disparités de cette pathologie est aujourd’hui expliquée. Il est donc nécessaire de poursuivre sur le rôle des contaminants de l’environnement. Enfin, le troisième axe s’intéresse à l’analyse spatiale et spatio-temporelle de contaminations des eaux souterraines par les ETM, en vue d’identifier de potentiels facteurs de risques environnementaux des maladies inflammatoires chroniques de l’intestin. La réalisation de ces travaux s’appuie sur plusieurs collaborations établies avec le Réseau REIN, le Registre EPIMAD et des équipes de recherche (EA4483 et EA2694 Université Lille 2, TVES EA4477 ULCO).A la suite de ces travaux de thèse, les perspectives de recherche sont de poursuivre le développement d’indicateurs intégrés d’exposition aux contaminations multiples des milieux environnementaux. Les résultats montrent également un manque de renseignement des bases de données environnementales par rapport aux registres de santé. Un travail est donc nécessaire afin de définir le contenu de ces bases, nécessaire pour caractériser la qualité des milieux et faciliter l’étude de l’interaction de l’Homme avec son environnement. / Environmental and social inequalities in health (ESIH) over territories are related to two cumulative dimensions: populations exposed to their living poor quality environment and the vulnerability of these populations to the environmental risk factors, which can affect health. This research deals with the Geographic Information Systems (GIS) applied to the field of environmental health. General purposes are the characterization of environmental media quality and the assessment of ESIH.Achieving these objectives requires a first step of harvest, genesis and formatting spatialized environmental databases. Such data are resulting from physico-chemical monitoring and biomonitoring. They were then mapped using GIS tools, including geostatistical spatial interpolation methods. On the over hand, spatial variability in the incidence of diseases were investigated using disease mapping methods (Standardized Incidence Ratios: SIR) and the detection of atypical clusters of events (scan statistics), which are based on disease registries. Finally, geographical ecological studies are developed to associate the environmental maps generated to health and socio-economic status. Thus, this work aims to answer the question \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"do people with poor state of health live in a poor quality environment?\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\" This question has been studied through three main researches.The first relates the characterization of trace elements burdens in the environment and the assessment of ESIH on neighborhood scale, over three territories in the Nord-Pas de Calais (NPdC) region. This research is conducted from measurements of biological burdens performed both in epiphytic lichens and humans and from a localized index of deprivation. The measured metals were considered individually, but also holistically by developing an integrated multimetallic index, in order to describe the general status of environmental pollution by metals. Environmental inequalities were observed on neighborhood scale in Dunkerque. Our results assume that trace elements burdens in populations are affected by environmental burdens.In our second research we revealed spatial disparities in the incidence of end stage renal disease (ESRD) on small area in the NPdC. Unlike other factors (diabetes, cardiovascular disease, medical practices), we highlighted the role of socio-economic status in the occurrence of such disparities. Only a part of the ESRD variability is currently explained. It is therefore necessary to focus on the environmental hypothesis.The third research focuses on the spatial and spatio-temporal analysis of groundwater contamination by trace elements, in order to identify potential environmental risk factors in the incidence of chronic inflammatory bowel disease.This work is based on several collaborations with the REIN network, the EPIMAD registry, and several research teams (EA4483 and EA2694 Université Lille 2, TVES EA4477 ULCO).Following this thesis, the research prospects are to pursue the development of integrated indicators to assess population exposure to the multiple environmental media contamination. The results also indicate a lack of information in environmental databases compared to health registries. A work is thus needed to define the content of such databases. These are necessary to characterize the environmental quality and to help the assessment of interaction between the populations and their living environment.
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Vybrané testy jednotkových kořenů v časových řadách / Selected Unit Root Tests in Time series

Fedorová, Darina January 2015 (has links)
The emphasis of this diploma thesis is placed on the verification of stationarity in time series using the Unit Root Tests and their most common modifications that are introduced in the theoretical part of this paper. Tests mainly by Dickey and Fuller, Phillips and Perron, and KPSS test are introduced as well as their modifications in the form of ERS, Ng and Perron, and Leybourne and McCabe tests. Moreover the HEGY test for testing stationarity in the seasonal Time series and Perron test of structural breaks for Time series with shocks are described. There is also outlined the process of testing multiple Unit Roots. The empirical part of this paper consists of simulations of AR(1) time series generated using the software R, their testing for stationarity by selected Unit Root tests and the comparison of power of these tests. The conclusion includes recommendations which tests and under what conditions are the most suitable for testing Time series for the presence of Unit Root.

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