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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.
91

The effects of sports drinks containing caffeine and carbohydrate on soccer-specific skill performance during match-induced fatigue

Jacobson, Marc A. 26 April 2011 (has links)
A ninety minute competitive soccer match consists of many intermittent sprints resulting in fatigue, and consequently, a reduction in skill performance. The combination of caffeine and carbohydrate (CHO) has been shown to have ergogenic effects which help maintain skill measures during fatiguing states, however, there has been little research investigating this combination on soccer performance. Therefore, the aim of this study was to examine the effects of three sports drinks, including a placebo (PLA), a 6% CHO drink, and CHO + caffeine (CCAF; 5 mg/Kg body mass (BM)) on soccer-specific skills, throughout a fatigue-inducing soccer match. Twelve male soccer players completed three ninety minute intersquad matches played outdoors on a grass field in a randomized crossover design. Players consumed 5 ml/kg BM 45 minutes prior to kickoff and 3 ml/kg BM every 15 minutes during match play. Soccer passing skill was measured using the Loughborough Soccer Passing Test (LSPT), shot speed, and 20m sprint performance were measured pre-match, immediately at halftime and immediately post-match. Countermovement jump (CMJ) was measured pre-match and post-match. Heart rate (HR) was measured continuously. Blood lactate, rating of perceived exertion (RPE), and perceived fatigue were assessed every fifteen minutes throughout the match. Urine was collected pre-match for analysis of urine specific gravity (USG). BM was measured pre-match and post-match. LSPT total performance time was significantly better in the CCAF trial compared to the PLA trial at halftime (55.3 ± 10.3 s vs 66.5 ±8.7 s, p = .027). There were also significant improvements in penalty time (CCAF 8.2 ± 7.6 s vs. PLA 16.6 ± 7.8 s, p = .042) and movement time (CCAF 8.2 ± 7.6 s vs. PLA 16.6 ± 7.8 s, p = .028) during the CCAF trial in comparison to the PLA at halftime. HR and blood lactate was elevated throughout the PLA trial in comparison to the CHO trial. There were no other significant findings. Most players (50% - 83%) started all three matches in a dehydrated state (USG > 1.020). The CHO trial had significantly lower sweat rates (0.83 ± 0.25 L/hr) than both the PLA trial (1.06 ± 0.26 L/hr, p = .038) and the CCAF trial (1.11 ± 0.19 L/hr, p = .009). The addition of caffeine to a CHO sports drink significantly improved passing performance (quicker completion time and fewer penalties accumulated) over a PLA. All three sports drinks appeared to be equally as effective in preventing deterioration of soccer skill performance during a game situation. This suggests that the total volume of fluid consumed is of greater importance than the type of fluid. Caffeine appeared to have limited ergogenic effects on skill performance without any negative consequences. / Graduate
92

Experimental Investigation Of Aerodynamic Interactions Of Vehicles In Close Folowing And Passing Situations

Gumusluol, Unsal 01 June 2006 (has links) (PDF)
In this Thesis study, aerodynamic interactions of vehicle models in close following and passing situations were investigated expeimentally. Effect of the inter-vehicle spacing and lateral distance on drag coefficients of two close-following vehicles were observed. Two different types of vehicle models were used in order to investigate the shape effect on aerodynamic vehicle interactions. Drag froces and surface pressures of the models at each situation were measured. Two different blockage correction methods on the basis of drag coefficient results were applied. Linear increments of drag coefficients were observed on leading and trailing MIRA models. Beacuse of their blunter shapes and sharp edges, the leading and trailing Ahmed Body models feel the presence of aerodynamic interactions substantially. The most important reduction in drag force occurs at the least vehicle spacing for both vehicle types. In the passing situations, it was observed that drag coefficients of MIRA models did not change considerably. However, big amount of changes were observed at all positions for Ahmed Body. Maximum values of drag coefficients were reached when the models were at side by side position for both vehicle types. In conclusion, it is possible to obtain more drag reductions with more numbers of vehicles in close-following. the lower drag coefficients in close-following operations caues to increase fuel savings and to reduce air pollution.
93

Passing as Gray: Texas Confederate Soldiers' Body Servants and the Exploitation of Civil War Memory

Elliott, Brian Alexander 05 1900 (has links)
This dissertation is an examination of the interactions of enslaved body servants with their Texas Confederate masters from the American Civil War through the early twentieth century. The seven chapters of this study follows the story of these individuals from the fires of the Civil War, through the turbulence of Reconstruction in Texas, the codification of "Lost Cause" memory in the American South, and the exploitation of that memory by both former body servants and their ex-Confederate counterparts. This study demonstrates that the primary experience of blacks in the Confederate service was not as soldiers, but as enslaved laborers and body servants. Body servants, or camp slaves, were physically and in some cases emotionally close to their enslavers in this war-time environment and played an important part in Confederate logistics and camp life. As freed peoples after the war, former body servants found ways to use the bonds forged during the war and the flawed ideas of Lost Cause memory as a means to navigate the brutal realities of life in post-Civil War Texas. By manipulating white conceptions of former body servants as "black Confederates," some African Americans effectively "passed as gray," an act that earned money, social recognition, and a semblance of security denied to African Americans that did not have any association to former Confederates. This study further reorients how scholars in the twenty-first century examine the myth of the "black Confederate" from simply a lie propagated by whites to validate their memory of the Civil War to a lens that can reveal yet another avenue through which dauntless African Americans used to survive, and in some cases thrive, in the depths of Jim Crow rule in the American South.
94

Optimization methods for side-chain positioning and macromolecular docking

Moghadasi, Mohammad 08 April 2016 (has links)
This dissertation proposes new optimization algorithms targeting protein-protein docking which is an important class of problems in computational structural biology. The ultimate goal of docking methods is to predict the 3-dimensional structure of a stable protein-protein complex. We study two specific problems encountered in predictive docking of proteins. The first problem is Side-Chain Positioning (SCP), a central component of homology modeling and computational protein docking methods. We formulate SCP as a Maximum Weighted Independent Set (MWIS) problem on an appropriately constructed graph. Our formulation also considers the significant special structure of proteins that SCP exhibits for docking. We develop an approximate algorithm that solves a relaxation of MWIS and employ randomized estimation heuristics to obtain high-quality feasible solutions to the problem. The algorithm is fully distributed and can be implemented on multi-processor architectures. Our computational results on a benchmark set of protein complexes show that the accuracy of our approximate MWIS-based algorithm predictions is comparable with the results achieved by a state-of-the-art method that finds an exact solution to SCP. The second problem we target in this work is protein docking refinement. We propose two different methods to solve the refinement problem. The first approach is based on a Monte Carlo-Minimization (MCM) search to optimize rigid-body and side-chain conformations for binding. In particular, we study the impact of optimally positioning the side-chains in the interface region between two proteins in the process of binding. We report computational results showing that incorporating side-chain flexibility in docking provides substantial improvement in the quality of docked predictions compared to the rigid-body approaches. Further, we demonstrate that the inclusion of unbound side-chain conformers in the side-chain search introduces significant improvement in the performance of the docking refinement protocols. In the second approach, we propose a novel stochastic optimization algorithm based on Subspace Semi-Definite programming-based Underestimation (SSDU), which aims to solve protein docking and protein structure prediction. SSDU is based on underestimating the binding energy function in a permissive subspace of the space of rigid-body motions. We apply Principal Component Analysis (PCA) to determine the permissive subspace and reduce the dimensionality of the conformational search space. We consider the general class of convex polynomial underestimators, and formulate the problem of finding such underestimators as a Semi-Definite Programming (SDP) problem. Using these underestimators, we perform a biased sampling in the vicinity of the conformational regions where the energy function is at its global minimum. Moreover, we develop an exploration procedure based on density-based clustering to detect the near-native regions even when there are many local minima residing far from each other. We also incorporate a Model Selection procedure into SSDU to pick a predictive conformation. Testing our algorithm over a benchmark of protein complexes indicates that SSDU substantially improves the quality of docking refinement compared with existing methods.
95

A Unified Robust Minimax Framework for Regularized Learning Problems

Zhou, Hongbo 01 May 2014 (has links)
Regularization techniques have become a principled tool for model-based statistics and artificial intelligence research. However, in most situations, these regularization terms are not well interpreted, especially on how they are related to the loss function and data matrix in a given statistic model. In this work, we propose a robust minimax formulation to interpret the relationship between data and regularization terms for a large class of loss functions. We show that various regularization terms are essentially corresponding to different distortions to the original data matrix. This supplies a unified framework for understanding various existing regularization terms, designing novel regularization terms based on perturbation analysis techniques, and inspiring novel generic algorithms. To show how to apply minimax related concepts to real-world learning tasks, we develop a new fault-tolerant classification framework to combat class noise for general multi-class classification problems; further, by studying the relationship between the majorizable function class and the minimax framework, we develop an accurate, efficient, and scalable algorithm for solving a large family of learning formulations. In addition, this work has been further extended to tackle several important matrix-decomposition-related learning tasks, and we have validated our work on various real-world applications including structure-from-motion (with missing data) and latent structure dictionary learning tasks. This work, composed of a unified formulation, a scalable algorithm, and promising applications in many real-world learning problems, contributes to the understanding of various hidden robustness in many learning models. As we show, many classical statistical machine learning models can be unified using this formulation and accurate, efficient, and scalable algorithms become available from our research.
96

Validação de instrumentos de habilidades técnicas ofensivas no basquetebol

Marramarco, Giuliano Tavares January 2012 (has links)
O objetivo geral deste trabalho é propor um instrumento de avaliação do nível de habilidades técnicas ofensivas do basquetebol para atletas e escolares de 10 a 11 anos. A mostra do estudo é de 64 meninos, dentre eles, 48 são escolares e 16 são atletas de basquetebol. Os testes propostos passaram primeiramente por um processo de validação de conteúdo, sendo considerado como válido, e posteriormente por uma validação de construto, através do método de grupos diferenciados, ao qual também teve os critérios atendidos. As habilidades técnicas a serem avaliadas são: drible, passe e arremesso. A reprodutibilidade dos testes foram avaliadas através de coeficientes de correlação intra-classe e correlação de alpha de Cronbach.Na verificação da objetividade foi utilizado também correlações intra-classe e alpha de Cronbach. Foi analisado a assimetria (skewness) e o achatamento (kurtosis) da curva. O teste de Shapiro Wilk foi utilizado para verificar a normalidade dos dados dos atletas. Foi utilizado um nível de significância de 5% para todas as análises. Para o estabelecimento de critérios de seleção em escolares a metodologia utilizada foi a técnica multivariada da Análise da Função Discriminante. Os resultados apresentados em relação a objetividade foram expressos através de alphas de Cronbach de 0,97. A reprodutibilidade dos dados de arremesso apresentou um aplha Cronbach de 0,88. Sobre os dados de passe a reprodutibilidade manifestou um alpha de 0,83, enquanto no drible foi de 0,96. Quanto ao estabelecimento de critérios de performance através da análise da função discriminante, demonstrou que todas a as variáveis utilizadas na equação entre elas, passe, drible e arremesso, tem poder de discriminar atletas e escolares. / The overall aim of this work isto propose a tool for assessing lhe level of technichal skills for offensive basketaball athletes and schollchildren of 10 to 11 years. The sample is 64 childrens, amog them, 48 are scholars and 16 are basketball players. The proposed tests passed first trough a process of content validation, being considered as valid, and later by a construct validation, through the method of differentiated groups, which had also met the criteria. The technichal skills to be assessed are dribbling, passing and shooting. The reliability of tests were evaluated using intra class correlation coefficients and Cronbach’s alpha correlation. On verification of intra evaluator reliability was also used intra-class correlations and Cronbach’s alpha. We analyzed the simetry (skewness) and flatenning (kurtosis) of the curve. The Shapiro Wilk test was used to verify the normality of the data of athletes. We used a significance level of 5% for all analyzes. To estabilish selection criteria in students the methodology used was the technique of multivariate analysis is discriminant function analysis. The results presented in relation to objectivity were expressed by Cronbach’s alphas of 0.97. The reproducibility of the data presented a shooting Cronbach alpha of 0.88. About the passing, the reproducibility showed na alpha of 0.83, while the dribbling was used discriminant function analysis and the result was shown that all variables used in this model, including, passing, dribbling and shooting has power to discriminate school athletes.
97

Segmentation vidéo et suivi d'objets multiples / Video segmentation and multiple object tracking

Kumar, Ratnesh 15 December 2014 (has links)
Dans cette thèse nous proposons de nouveaux algorithmes d'analyse vidéo. La première contribution de cette thèse concerne le domaine de la segmentation de vidéos avec pour objectif d'obtenir une segmentation dense et spatio-temporellement cohérente. Nous proposons de combiner les aspects spatiaux et temporels d'une vidéo en une seule notion, celle de Fibre. Une fibre est un ensemble de trajectoires qui sont spatialement connectées par un maillage. Les fibres sont construites en évaluant simultanément les aspects spatiaux et temporels. Par rapport a l’état de l'art une segmentation de vidéo a base de fibres présente comme avantages d’accéder naturellement au voisinage grâce au maillage et aux correspondances temporelles pour la plupart des pixels de la vidéo. De plus, cette segmentation à base de fibres a une complexité quasi linéaire par rapport au nombre de pixels. La deuxième contribution de cette thèse concerne le suivi d'objets multiples. Nous proposons une approche de suivi qui utilise des caractéristiques des points suivis, la cinématique des objets suivis et l'apparence globale des détections. L'unification de toutes ces caractéristiques est effectuée avec un champ conditionnel aléatoire. Ensuite ce modèle est optimisé en combinant les techniques de passage de message et une variante de processus ICM (Iterated Conditional Modes) pour inférer les trajectoires d'objet. Une troisième contribution mineure consiste dans le développement d'un descripteur pour la mise en correspondance d'apparences de personne. Toutes les approches proposées obtiennent des résultats compétitifs ou meilleurs (qualitativement et quantitativement) que l’état de l'art sur des base de données. / In this thesis we propose novel algorithms for video analysis. The first contribution of this thesis is in the domain of video segmentation wherein the objective is to obtain a dense and coherent spatio-temporal segmentation. We propose joining both spatial and temporal aspects of a video into a single notion Fiber. A fiber is a set of trajectories which are spatially connected by a mesh. Fibers are built by jointly assessing spatial and temporal aspects of the video. Compared to the state-of-the-art, a fiber based video segmentation presents advantages such as a natural spatio-temporal neighborhood accessor by a mesh, and temporal correspondences for most pixels in the video. Furthermore, this fiber-based segmentation is of quasi-linear complexity w.r.t. the number of pixels. The second contribution is in the realm of multiple object tracking. We proposed a tracking approach which utilizes cues from point tracks, kinematics of moving objects and global appearance of detections. Unification of all these cues is performed on a Conditional Random Field. Subsequently this model is optimized by a combination of message passing and an Iterated Conditional Modes (ICM) variant to infer object-trajectories. A third, minor, contribution relates to the development of suitable feature descriptor for appearance matching of persons. All of our proposed approaches achieve competitive and better results (both qualitatively and quantitatively) than state-of-the-art on open source datasets.
98

Calcul haute performance pour la simulation d'interactions fluide-structure

Partimbene, Vincent 25 April 2018 (has links) (PDF)
Cette thèse aborde la résolution des problèmes d'interaction fluide-structure par un algorithme consistant en un couplage entre deux solveurs : un pour le fluide et un pour la structure. Pour assurer la cohérence entre les maillages fluide et structure, on considère également une discrétisation de chaque domaine par volumes finis. En raison des difficultés de décomposition du domaine en sous-domaines, nous considérons pour chaque environnement un algorithme parallèle de multi-splitting (ou multi-décomposition) qui correspond à une présentation unifiée des méthodes de sous-domaines avec ou sans recouvrement. Cette méthode combine plusieurs applications de points fixes contractantes et nous montrons que, sous des hypothèses appropriées, chaque application de points fixes est contractante dans des espaces de dimensions finies normés par des normes hilbertiennes et non-hilbertiennes. De plus, nous montrons qu'une telle étude est valable pour les résolutions parallèles synchrones et plus généralement asynchrones de grands systèmes linéaires apparaissant lors de la discrétisation des problèmes d'interaction fluide-structure et peut être étendue au cas où le déplacement de la structure est soumis à des contraintes. Par ailleurs, nous pouvons également considérer l’analyse de la convergence de ces méthodes de multi-splitting parallèles asynchrones par des techniques d’ordre partiel, lié au principe du maximum discret, aussi bien dans le cadre linéaire que dans celui obtenu lorsque les déplacements de la structure sont soumis à des contraintes. Nous réalisons des simulations parallèles pour divers cas test fluide-structure sur différents clusters, en considérant des communications bloquantes et non bloquantes. Dans ce dernier cas nous avons eu à résoudre une difficulté d'implémentation dans la mesure où une erreur irrécupérable survenait lors de l'exécution ; cette difficulté a été levée par introduction d’une méthode assurant la terminaison de toutes les communications non bloquantes avant la mise à jour du maillage. Les performances des simulations parallèles sont présentées et analysées. Enfin, nous appliquons la méthodologie présentée précédemment à divers contextes d'interaction fluide-structure de type industriel sur des maillages non structurés, ce qui constitue une difficulté supplémentaire.
99

Validação de instrumentos de habilidades técnicas ofensivas no basquetebol

Marramarco, Giuliano Tavares January 2012 (has links)
O objetivo geral deste trabalho é propor um instrumento de avaliação do nível de habilidades técnicas ofensivas do basquetebol para atletas e escolares de 10 a 11 anos. A mostra do estudo é de 64 meninos, dentre eles, 48 são escolares e 16 são atletas de basquetebol. Os testes propostos passaram primeiramente por um processo de validação de conteúdo, sendo considerado como válido, e posteriormente por uma validação de construto, através do método de grupos diferenciados, ao qual também teve os critérios atendidos. As habilidades técnicas a serem avaliadas são: drible, passe e arremesso. A reprodutibilidade dos testes foram avaliadas através de coeficientes de correlação intra-classe e correlação de alpha de Cronbach.Na verificação da objetividade foi utilizado também correlações intra-classe e alpha de Cronbach. Foi analisado a assimetria (skewness) e o achatamento (kurtosis) da curva. O teste de Shapiro Wilk foi utilizado para verificar a normalidade dos dados dos atletas. Foi utilizado um nível de significância de 5% para todas as análises. Para o estabelecimento de critérios de seleção em escolares a metodologia utilizada foi a técnica multivariada da Análise da Função Discriminante. Os resultados apresentados em relação a objetividade foram expressos através de alphas de Cronbach de 0,97. A reprodutibilidade dos dados de arremesso apresentou um aplha Cronbach de 0,88. Sobre os dados de passe a reprodutibilidade manifestou um alpha de 0,83, enquanto no drible foi de 0,96. Quanto ao estabelecimento de critérios de performance através da análise da função discriminante, demonstrou que todas a as variáveis utilizadas na equação entre elas, passe, drible e arremesso, tem poder de discriminar atletas e escolares. / The overall aim of this work isto propose a tool for assessing lhe level of technichal skills for offensive basketaball athletes and schollchildren of 10 to 11 years. The sample is 64 childrens, amog them, 48 are scholars and 16 are basketball players. The proposed tests passed first trough a process of content validation, being considered as valid, and later by a construct validation, through the method of differentiated groups, which had also met the criteria. The technichal skills to be assessed are dribbling, passing and shooting. The reliability of tests were evaluated using intra class correlation coefficients and Cronbach’s alpha correlation. On verification of intra evaluator reliability was also used intra-class correlations and Cronbach’s alpha. We analyzed the simetry (skewness) and flatenning (kurtosis) of the curve. The Shapiro Wilk test was used to verify the normality of the data of athletes. We used a significance level of 5% for all analyzes. To estabilish selection criteria in students the methodology used was the technique of multivariate analysis is discriminant function analysis. The results presented in relation to objectivity were expressed by Cronbach’s alphas of 0.97. The reproducibility of the data presented a shooting Cronbach alpha of 0.88. About the passing, the reproducibility showed na alpha of 0.83, while the dribbling was used discriminant function analysis and the result was shown that all variables used in this model, including, passing, dribbling and shooting has power to discriminate school athletes.
100

Decision-making patterns and self-confidence in high school adolescents / Patrones de toma de decisiones y autoconfianza en adolescentes bachilleres

Luna Bernal, Alejandro César Antonio, Laca Arocena, Francisco Augusto Vicente 25 September 2017 (has links)
The present study aimed to analyse the factor structure of the Melbourne Decision Making Questionnaire (DMQ-II), and to examine the relationships between the factors identified and Self-confidence, in order to conceptualize the decision-making process in adolescents under the Conflict Model of Decision Making. Participants were 992 Mexican high-school students, aged between 15 and 19 years. The three factors were identified as decision-making patterns in adolescents: a) Vigilance, b) Hipervigilance/Procrastination and c) Buck-passing. The Self-confidence showed a positive effect on Vigilance, and a negative effect on theother two patterns. Results are discussed considering the literature on decision making in adolescence. / El presente estudio se propuso analizar la estructura factorial del Cuestionario Melbourne sobre Toma de Decisiones, y estudiar las relaciones entre los factores identificados y la Autoconfianza, con la finalidad de conceptualizar la toma de decisiones de los adolescentes en elmarco del Modelo de Conflicto de Decisión. Los participantes fueron 992 estudiantes mexicanos de bachillerato con edades entre 15 y 19 años. Se identificaron tres factores interpretados como patrones de toma de decisiones en adolescentes: a) Vigilancia, b) Procrastinación/Hipervigilancia y c) Transferencia. La Autoconfianza resultó tener un efecto positivo sobre Vigilancia, y un efecto negativo sobre los otros dos patrones. Se discuten estos y otros resultados considerando la literatura sobre toma de decisiones en la adolescencia.

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