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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.
1

Impacts of climate variabilities on maize yield across the US: Insights from a Bayesian modeling analysis

Hu, Tongxi, Hu 22 October 2018 (has links)
No description available.
2

Stratégie de modélisation et de simulation des assemblages de structures aéronautiques en contexte incertain / Modeling and simulation strategy of aeronautical assemblies in an uncertain context

Gant, Florent 19 December 2011 (has links)
Ce travail de recherche présente une stratégie de modélisation et de dimensionnement pour les assemblages boulonnés en milieu aéronautique. Dans le cas du dimensionnement de grandes structures, les bureaux d’étude se servent habituellement de techniques dites de « zoom structural ». Elles permettent de gérer les ressources numériques à disposition, avec des modèles simples et de grande taille à l’échelle globale, et des modèles plus complexes à l’échelle locale. Cette étude s‘insère dans le cadre d’un processus de zoom structural dans lequel les structures étudiées présentent un très grand nombre de fixations. Un premier travail consiste à proposer une modélisation pertinente des fixations à l’échelle globale. Dans une seconde partie, les dispersions de comportement observées dans les fixations boulonnées sont prises en compte par l’utilisation de la théorie des méconnaissances. Une technique de recalage de la modélisation complète est ensuite proposée afin de tirer partie d’éventuels essais réels ou numériques. Enfin, la stratégie proposée est appliquée sur des cas d’assemblages boulonnés de type aéronautique. Les avantages, mais aussi les limites de l’utilisation d’une telle stratégie y sont discutés. / The objective of this work is to develop a modeling strategy for assemblies involving multiple joints in an aeronautical predesign context. In the process of designing large structures, industrial engineers usually get around computational limitations by using submodeling techniques. In order to take into account phenomena which vary during the global representation of the submodeling process, we propose a modeling approach for the scattering of these phenomena based on the Lack-Of-Knowledge (LOK) theory. The LOK model associated with a relevant deterministic joint model is updated based on experimental or simulated data. The proposed strategy is discussed and illustrated by the case of multiple-joint assemblies typical of those used in aeronautics.
3

A NeRF for All Seasons

Michael Donald Gableman (16632723) 08 August 2023 (has links)
<p> </p> <p>As a result of Shadow NeRF and Sat-NeRF, it is possible to take the solar angle into account in a NeRF-based framework for rendering a scene from a novel viewpoint using satellite images for training. Our work extends those contributions and shows how one can make the renderings season-specific. Our main challenge was creating a Neural Radiance Field (NeRF) that could render seasonal features independently of viewing angle and solar angle</p> <p>while still being able to render shadows. We teach our network to render seasonal features by introducing one more input variable — time of the year. However, the small training datasets typical of satellite imagery can introduce ambiguities in cases where shadows are present in the same location for every image of a particular season. We add additional terms to the loss function to discourage the network from using seasonal features for accounting for shadows. We show the performance of our network on eight Areas of Interest containing images captured by the Maxar WorldView-3 satellite. This evaluation includes tests measuring the ability of our framework to accurately render novel views, generate height maps, predict shadows, and specify seasonal features independently from shadows. Our ablation</p> <p>studies justify the choices made for network design parameters. Also included in this work is a novel approach to space carving which merges multiple features and consistency metrics</p> <p>at different spatial scales to create higher quality digital surface map than is possible using standard RGB features.</p>
4

A Corrente do Brasil ao largo de Santos: medições diretas / Brazil Current offshore Santos: direct measurements

Souza, Maria Cristina de Arruda 13 September 2000 (has links)
O comportamento da Corrente do Brasil (CB) ao largo de Santos foi determinado a partir de medições diretas de velocidade e temperatura realizadas como parte do projeto COROAS. Foram lançados três fundeios, sobre as isóbatas de 100 m (C1), 200 m (C2) e 1000 m (C3). Os dados obtidos passaram por diversas análises - estatística descritiva, análises gráficas com o auxílio de rosas de distribuição, “stickplots", séries temporais e hodógrafos e análise de Funções Empíricas Ortogonais (EOF). Os resultados mostram que o ponto C1 sofre grande influência meteorológica – em todas as estações sazonais e profundidades amostradas, há predominância do fluxo para SW, mas este apresenta grande variabilidade devida à sua alternância com o fluxo para NE. Essa variabilidade, com escala subinecial, mostra que durante a maior parte do tempo, o ponto C1 esteve imerso num regime típico de plataforma continental, e não de correntes de contorno oeste. O fluxo da CB atinge essa região apenas esporadicamente. Foi observada a bipolaridade entre as intrusões das massas de água transportadas pela CB (ACAS e AT), como caracterizada por Castro (1996). Nos pontos C2 e C3, a presença da CB é marcante. Nos três primeiros níveis, persistiu um forte fluxo para SW, com intensidades da ordem de 1 m/s. A variabilidade temporal dessas correntes é pequena, principalmente nos três níveis superiores. No nível de 698 m, em C3, predominou o fluxo para NE da Água Intermediária Antártica. As melhores definições do fluxo da CB nas três profundidades superiores dos fundeios C2 e C3 foram observadas na primavera/93 e no verão/94. A variabilidade do fluxo, nos três fundeios, é bem descrita pelo comportamento das EOF. Um vórtice ciclônico, de núcleo frio, com período de 20 dias e escala vertical de aproximadamente 700 m, foi registrado em fevereiro de 1993. Indícios desse vórtice foram detectados até no ponto C1. O transporte de volume da CB, entre a quebra da plataforma e o talude, possui um valor médio de –2,01 &#61617; 0,98 Sv, relativamente ao nível de 300 m e tem sentido predominante para SW. Foram realizados alguns estudos dos casos de variabilidade da corrente. Esses estudos ilustram o modelo de Lee et al.(1981), sobre surgimento e características dos vórtices ciclônicos de núcleo frio, e o transporte de Ekman. / Current and temperature measurements, off shore Santos (23&#61616; 56’ S - 046&#61616; 19’ W), were performed to determine the behaviour of the Brazil Current (BC), during COROAS Project. Three moored arrays were launched on the 100 m (C1), 200 m (C2) e 1000 m (C3) isobaths. Several analysis were performed – statistical, compass plots, time series and Empirical Orthogonal Functions (EOF). On the C1 point, external continental shelf, meteorological influence is notable – in all seasons and depths sampled, predominate southwestward currents, with big variability in consequence of the alternating northwestward. This variability, with subinercial scale, shows that C1 point was immersed in a typical continental shelf pattern, almost all the time, and not in a western boundary pattern. Brazil Current flow reaches this region sporadically. It was observed a bipolarity between water masses intrusions, South Atlantic Central Water and Tropical Water, transported by BC, supporting earlier observations from Castro (1996). On the three first levels of C2 (continental break) and C3 (continental slope) points, Brazil Current is a well-developed boundary current southwestward, reaching speeds of 1 m/s, with small time variability. On C3 point, 698 m depth, predominate Intermediate Antarctic Water northwestward flow. The best definitions of the BC flow were observed during Spring (1993) and Summer (1994). A good representation of the observed variability was obtained by EOFs . A cyclonic, cold core BC eddy with period of 20 days and vertical scale approximately of 700 m, was detected in February (1993). This eddy seems to have reached C1 point. Brazil Current mean volume transport, between continental break and continental slope , was 2.01 + 0.98 Sv, relative to 300 m and southwestward, predominately. Some cases of current variability were studied. These cases illustrate the Lee et al. (1981) model about onset and features of the cyclonic cold core eddies and Ekman transport.
5

A Corrente do Brasil ao largo de Santos: medições diretas / Brazil Current offshore Santos: direct measurements

Maria Cristina de Arruda Souza 13 September 2000 (has links)
O comportamento da Corrente do Brasil (CB) ao largo de Santos foi determinado a partir de medições diretas de velocidade e temperatura realizadas como parte do projeto COROAS. Foram lançados três fundeios, sobre as isóbatas de 100 m (C1), 200 m (C2) e 1000 m (C3). Os dados obtidos passaram por diversas análises - estatística descritiva, análises gráficas com o auxílio de rosas de distribuição, “stickplots”, séries temporais e hodógrafos e análise de Funções Empíricas Ortogonais (EOF). Os resultados mostram que o ponto C1 sofre grande influência meteorológica – em todas as estações sazonais e profundidades amostradas, há predominância do fluxo para SW, mas este apresenta grande variabilidade devida à sua alternância com o fluxo para NE. Essa variabilidade, com escala subinecial, mostra que durante a maior parte do tempo, o ponto C1 esteve imerso num regime típico de plataforma continental, e não de correntes de contorno oeste. O fluxo da CB atinge essa região apenas esporadicamente. Foi observada a bipolaridade entre as intrusões das massas de água transportadas pela CB (ACAS e AT), como caracterizada por Castro (1996). Nos pontos C2 e C3, a presença da CB é marcante. Nos três primeiros níveis, persistiu um forte fluxo para SW, com intensidades da ordem de 1 m/s. A variabilidade temporal dessas correntes é pequena, principalmente nos três níveis superiores. No nível de 698 m, em C3, predominou o fluxo para NE da Água Intermediária Antártica. As melhores definições do fluxo da CB nas três profundidades superiores dos fundeios C2 e C3 foram observadas na primavera/93 e no verão/94. A variabilidade do fluxo, nos três fundeios, é bem descrita pelo comportamento das EOF. Um vórtice ciclônico, de núcleo frio, com período de 20 dias e escala vertical de aproximadamente 700 m, foi registrado em fevereiro de 1993. Indícios desse vórtice foram detectados até no ponto C1. O transporte de volume da CB, entre a quebra da plataforma e o talude, possui um valor médio de –2,01 &#61617; 0,98 Sv, relativamente ao nível de 300 m e tem sentido predominante para SW. Foram realizados alguns estudos dos casos de variabilidade da corrente. Esses estudos ilustram o modelo de Lee et al.(1981), sobre surgimento e características dos vórtices ciclônicos de núcleo frio, e o transporte de Ekman. / Current and temperature measurements, off shore Santos (23&#61616; 56’ S - 046&#61616; 19’ W), were performed to determine the behaviour of the Brazil Current (BC), during COROAS Project. Three moored arrays were launched on the 100 m (C1), 200 m (C2) e 1000 m (C3) isobaths. Several analysis were performed – statistical, compass plots, time series and Empirical Orthogonal Functions (EOF). On the C1 point, external continental shelf, meteorological influence is notable – in all seasons and depths sampled, predominate southwestward currents, with big variability in consequence of the alternating northwestward. This variability, with subinercial scale, shows that C1 point was immersed in a typical continental shelf pattern, almost all the time, and not in a western boundary pattern. Brazil Current flow reaches this region sporadically. It was observed a bipolarity between water masses intrusions, South Atlantic Central Water and Tropical Water, transported by BC, supporting earlier observations from Castro (1996). On the three first levels of C2 (continental break) and C3 (continental slope) points, Brazil Current is a well-developed boundary current southwestward, reaching speeds of 1 m/s, with small time variability. On C3 point, 698 m depth, predominate Intermediate Antarctic Water northwestward flow. The best definitions of the BC flow were observed during Spring (1993) and Summer (1994). A good representation of the observed variability was obtained by EOFs . A cyclonic, cold core BC eddy with period of 20 days and vertical scale approximately of 700 m, was detected in February (1993). This eddy seems to have reached C1 point. Brazil Current mean volume transport, between continental break and continental slope , was 2.01 + 0.98 Sv, relative to 300 m and southwestward, predominately. Some cases of current variability were studied. These cases illustrate the Lee et al. (1981) model about onset and features of the cyclonic cold core eddies and Ekman transport.
6

Estudo e definição de uma linha de produtos de software para o desenvolvimento de aplicações educacionais móveis / Study and definition of a software product line for the development of mobile learning applications

Falvo Júnior, Venilton 07 April 2015 (has links)
A popularização dos dispositivos móveis em todas as camadas sociais tem motivado o desenvolvimento de aplicações educacionais móveis, denominadas aplicações de m-learning. Neste cenário, as aplicações existentes, mesmo possuindo diversos benefícios e facilidades no que diz respeito ao ensino e aprendizagem, apresentam problemas e desafios relacionados, sobretudo no que se refere ao desenvolvimento, reuso e padronização arquitetural. Por outro lado, na vertente do reúso de software, percebe-se uma crescente adoção do conceito de Linha de Produtos de Software (LPS). Esse paradigma possibilita às organizações explorar as similaridades e variabilidades de seus produtos, aumentando a reutilização de artefatos e, como consequência, diminuindo custos e tempo de desenvolvimento. Neste trabalho é apresentada uma LPS voltada ao domínio das aplicações de m-learning, denominada M-SPLearning. A proposição da M-SPLearning envolveu desde o estudo inicial para a obtenção de uma análise de domínio efetiva, até a implementação dos componentes previamente analisados. A LPS concebida teve seus respectivos produtos avaliados experimentalmente no cenário industrial, fornecendo evidências de que sua utilização pode acelerar o time-to-market de produtos de m-learning, com um número reduzido de defeitos. / The popularity of mobile devices in all social classes has motivated the development of mobile educational applications, called m-learning applications. The existing applications, even having many benefits and facilities in relation to teaching and learning, also have problems and challenges, especially regarding the development, reuse and architectural standardization. Particularly, there is an increasing adoption of the concept of Software Product Line (SPL) in researches related to reuse. This paradigm enables organizations to explore the similarities and variabilities of their products, increasing the reuse of artifacts and, consequently, reducing costs and development time. This work presents an SPL focused on the domain of m-learning applications, named M-SPLearning. The development of M-SPLearning has comprised since the initial study for an effective domain analysis until the implementation of the components previously analyzed. Such SPL had its products experimentally evaluated in the industrial scenario, providing evidences that its use can accelerate the time-to-market of m-learning applications, with a reduced number of faults.
7

Variabilité pharmacocinétique des anti-cancéreux : Application à la vinorelbine et au lapatinib / Pharmacokinetic variability of anticancer drugs : application with vinorelbine and lapatinib

Rezai Gharahbolagh, Keyvan 23 January 2012 (has links)
La mise en évidence de la variabilité pharmacocinétique et/ou pharmacodynamique permet l’optimisation de l’utilisation des cytotoxiques. L’association des thérapies ciblées à la chimiothérapie conventionnelle peut apporter des avantages supplémentaires en termes de bénéfice thérapeutique, mais aussi peut provoquer des interactions médicamenteuses et augmenter les variabilités interindividuelles. Les interactions médicamenteuses sont maintenant connues pour avoir un impact significatif sur l'élimination des médicaments.Le premier volet de ces travaux consiste à mesurer les concentrations sanguines de deux molécules (le lapatinib et la vinorelbine) chez les patientes et à les utiliser pour la modélisation pharmacocinétique. Cette modélisation a clairement montré l’influence du poids et du nombre des plaquettes sur la pharmacocinétique de la vinorelbine permettant ainsi de diminuer les variabilités pharmacocinétiques. Elle a également mis en évidence l’influence du lapatinib sur la pharmacocinétique de la vinorelbine. Cependant, compte tenu de l’absence de groupe témoin, nous n’avons pas réussi à obtenir une significativité statistique pour ces résultats. En parallèle, aucune influence de la vinorelbine sur le comportement pharmacocinétique du lapatinib n’a été mise en évidence.Le second volet concerne la modélisation de la réponse et de la tolérance des patientes pour cette association médicamenteuse (modélisation pharmacodynamique). La neutropénie est la toxicité dose-limitante et comme le lapatinib n’est pas connu pour être myélotoxique, nous avons modélisé cette toxicité par rapport au comportement pharmacocinétique de la vinorelbine. Là encore, nous avons observé une très forte tendance quant à l’influence du lapatinib sur la myélotoxicité de la vinorelbine. Concernant l’efficacité de cette association, la modélisation de l’évolution de la croissance tumorale a mis en évidence une synergie d’action entre ces deux molécules. A notre connaissance c’est la première fois qu’une telle modélisation tant du point de vue de la tolérance que de celui de la réponse, est réalisée lors d’une association de chimiothérapie classique et d’une thérapeutique ciblée.La modélisation PK-PD de population des médicaments anticancéreux peut apporter une aide précieuse aux cliniciens dans ce domaine. Elle peut également être essentielle dans la prise de décision clinique précoce. / The identification of sources of pharmacokinetic and / or pharmacodynamic variabilities, optimizes the use of cytotoxic agents. The combination of targeted therapies with conventional drugs may provide additional benefits in terms of therapeutic benefit, but also can cause drug interactions and increased variability. Drug interactions are known to have a significant impact on drug disposition.The first part of this work is to measure blood concentrations of two molecules (lapatinib and vinorelbine) in patients and to perform pharmacokinetic modeling. This modeling clearly showed the influence of weight and the platelet number on the pharmacokinetics of vinorelbine reducing thereby the pharmacokinetic variabilities. It also highlighted the influence of lapatinib on the pharmacokinetics of vinorelbine. However, due to the lack of control group, we failed to obtain statistical significance for these results. In parallel, no effect of vinorelbine on the pharmacokinetics of lapatinib has been detected.The second part concerns the modeling of the response and tolerance of patients for this drug combination (pharmacodynamic modeling). Neutropenia was detected as the dose-limiting toxicity of the combination and the fact that lapatinib is not known to be myelotoxic, we performed toxicity modeling based on the pharmacokinetics of vinorelbine. Again, we observed a strong tendency on the influence of lapatinib on the myelotoxicity of vinorelbine. Regarding the efficacy of this combination, tumor growth modeling showed a synergistic action between the two molecules. To our knowledge this is the first time that such a model, both in terms of tolerance and response, is implemented in a combination of conventional chemotherapy and targeted therapy.Population PK-PD modeling of cancer drugs can provide valuable assistance to clinicians in this field. It can also be essential in the early clinical decision making.
8

Estudo e definição de uma linha de produtos de software para o desenvolvimento de aplicações educacionais móveis / Study and definition of a software product line for the development of mobile learning applications

Venilton Falvo Júnior 07 April 2015 (has links)
A popularização dos dispositivos móveis em todas as camadas sociais tem motivado o desenvolvimento de aplicações educacionais móveis, denominadas aplicações de m-learning. Neste cenário, as aplicações existentes, mesmo possuindo diversos benefícios e facilidades no que diz respeito ao ensino e aprendizagem, apresentam problemas e desafios relacionados, sobretudo no que se refere ao desenvolvimento, reuso e padronização arquitetural. Por outro lado, na vertente do reúso de software, percebe-se uma crescente adoção do conceito de Linha de Produtos de Software (LPS). Esse paradigma possibilita às organizações explorar as similaridades e variabilidades de seus produtos, aumentando a reutilização de artefatos e, como consequência, diminuindo custos e tempo de desenvolvimento. Neste trabalho é apresentada uma LPS voltada ao domínio das aplicações de m-learning, denominada M-SPLearning. A proposição da M-SPLearning envolveu desde o estudo inicial para a obtenção de uma análise de domínio efetiva, até a implementação dos componentes previamente analisados. A LPS concebida teve seus respectivos produtos avaliados experimentalmente no cenário industrial, fornecendo evidências de que sua utilização pode acelerar o time-to-market de produtos de m-learning, com um número reduzido de defeitos. / The popularity of mobile devices in all social classes has motivated the development of mobile educational applications, called m-learning applications. The existing applications, even having many benefits and facilities in relation to teaching and learning, also have problems and challenges, especially regarding the development, reuse and architectural standardization. Particularly, there is an increasing adoption of the concept of Software Product Line (SPL) in researches related to reuse. This paradigm enables organizations to explore the similarities and variabilities of their products, increasing the reuse of artifacts and, consequently, reducing costs and development time. This work presents an SPL focused on the domain of m-learning applications, named M-SPLearning. The development of M-SPLearning has comprised since the initial study for an effective domain analysis until the implementation of the components previously analyzed. Such SPL had its products experimentally evaluated in the industrial scenario, providing evidences that its use can accelerate the time-to-market of m-learning applications, with a reduced number of faults.
9

Optimisation fiabiliste des performances énergétiques des bâtiments / Reliability based optimization of energetic performances of buildings

Aïssani, Amina 14 March 2016 (has links)
Dans un contexte de forte compétitivité économique et de respect de l’environnement, de nombreuses actions sont entreprises chaque année dans le but d’améliorer la performance énergétique des bâtiments. En phase de conception, le recours à la simulation permet d’évaluer les différentes alternatives au regard de la performance énergétique et du confort des occupants et constitue ainsi un outil d’aide à la décision incontournable. Toutefois, il est courant d’observer des écarts entre les performances énergétiques réelles et celles prévues lors de la conception. Cette thèse porte sur l’amélioration du processus de conception de l’isolation dans le but de limiter les déviations des consommations réelles par rapport à celles prévues lors des simulations. Dans un premier temps, nous situons le contexte énergétique actuel puis nous présentons les différentes sources d’incertitudes qui affectent les résultats des simulations. Dans ce travail, nous nous intéressons particulièrement à la variabilité des propriétés thermophysiques des isolants, au caractère variable de la mise en œuvre et à l’impact du changement climatique. Des études expérimentales ont permis de quantifier l’incertitude associée à la performance des matériaux sains d’une part, et celle associée à des isolants défectueux d’autre part. Un couplage entre des techniques de thermographie infrarouge et des modèles éléments finis ont permis de proposer des modèles paramétriques permettant d’évaluer la performance effective d’un isolant défectueux, en fonction du type et de la taille du défaut dans l’isolant. Pour une bonne estimation à long terme de la performance de l’isolation, il est nécessaire d’intégrer les prévisions météorologiques. Ces dernières sont généralement estimées sur la base des données historiques de la région. Toutefois, il est encore difficile de prévoir avec exactitude l’évolution climatique car elle dépend de nombreux facteurs socio-économiques, démographiques et environnementaux. Dans ce travail, nous proposons de considérer les différents scénarios climatiques proposés par les climatologues et de prendre en compte leur variabilité de manière à vérifier la fiabilité de l’isolation. Enfin, nous proposons d’utiliser des approches probabilistes pour intégrer ces différents types d’incertitudes dans le processus de simulation. Pour optimiser le dimensionnement de l’isolation, nous proposons une méthodologie de conception basée sur la fiabilité. Un nouveau modèle de coût est également proposé dans le but d’améliorer l’aide à la décision, en considérant les pertes indirectes, jusqu’à présent négligées dans la conception. / In the context of growing world energy demand and environmental degradation, many actions are undertaken each year to improve the energy performance of buildings. During the design stage, the use of building energy simulations remains a valuable tool as it evaluates the possible options in terms of energy performance and comfort. However, as precision requirements increase, it becomes essential to assess the uncertainties associated with input data in simulation. This thesis focuses on the insulation design process under uncertainty, in order to limit gaps between real and predicted performance for better control of energy consumptions. This work firstly presents the current alarming energy context. We consider the main uncertainties that affect the insulation, mainly the variability of the thermophysical properties, the uncertainty on climate and the uncertainties due to workmanship defects. Experimental studies were carried out to evaluate the uncertainty associated to the intrinsic performance of healthy insulation materials on one hand, and those associated to defects in insulations on the other hand. A coupling between thermography techniques and finite element models was used to provide analytical models that assess the effective thermal performance of a defective insulation, according to the type and size of the defect. As the performance of insulation also depends on climate, it is necessary to integrate future weather data to evaluate the energy consumption. These weather data are generally estimated based on the historical climatic data of the region. However, it is still difficult to predict climate change as it depends on many uncontrollable factors. In this work, we consider the different climate scenarios proposed by climate expert groups, and the uncertainty associated to each scenario to evaluate the reliability of the insulation and to improve the decision making process. Finally, we propose a probabilistic approach to integrate uncertainties in simulation and an optimization methodology based on reliability. A new cost formulation is also proposed to improve the decision-making, through indirect losses related to comfort, pollution and living space losses.
10

A Geometric Approach to Visualization of Variability in Univariate and Multivariate Functional Data

Xie, Weiyi 07 December 2017 (has links)
No description available.

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