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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.
371

"Enumeração dos fibrados vetoriais sobre superfícies fechadas" / "Enumeration of vector bundles over closed surfaces"

Melo, Thiago de 08 April 2005 (has links)
O objetivo desse trabalho é fazer uma enumeração dos fibrados planos reais sobre algumas superfícies, como por exemplo, a esfera e o g-toro. Entre outras ferramentas, utilizamos a co-homologia das superfícies, com coeficientes locais, e também o método desenvolvido por Larmore para contar classes de homotopia de levantamento de funções. / The aim of this work is enumerate the plane bundles over some surfaces, for example the sphere and the g-torus. Among other tools we used cohomology of the surfaces with local coefficients and also the method developed by Larmore to count homotopy classes of lifting of functions.
372

Application of LabVIEW and myRIO to voice controlled home automation

Lindstål, Tim, Marklund, Daniel January 2019 (has links)
The aim of this project is to use NI myRIO and LabVIEW for voice controlled home automation. The NI myRIO is an embedded device which has a Xilinx FPGA and a dual-core ARM Cortex-A9processor as well as analog input/output and digital input/output, and is programmed with theLabVIEW, a graphical programming language. The voice control is implemented in two differentsystems. The first system is based on an Amazon Echo Dot for voice recognition, which is acommercial smart speaker developed by Amazon Lab126. The Echo Dot devices are connectedvia the Internet to the voice-controlled intelligent personal assistant service known as Alexa(developed by Amazon), which is capable of voice interaction, music playback, and controllingsmart devices for home automation. This system in the present thesis project is more focusingon myRIO used for the wireless control of smart home devices, where smart lamps, sensors,speakers and a LCD-display was implemented. The other system is more focusing on myRIO for speech recognition and was built on myRIOwith a microphone connected. The speech recognition was implemented using mel frequencycepstral coefficients and dynamic time warping. A few commands could be recognized, includinga wake word ”Bosse” as well as other four commands for controlling the colors of a smart lamp. The thesis project is shown to be successful, having demonstrated that the implementation ofhome automation using the NI myRIO with two voice-controlled systems can correctly controlhome devices such as smart lamps, sensors, speakers and a LCD-display.
373

Análise geoestatística de mapas temáticos da produtividade da soja com diferentes grades amostrais / Geostatistical analysis of thematic maps of soybean yield with differente sampling grids

Kestring, Franciele Buss Frescki 07 July 2011 (has links)
Made available in DSpace on 2017-07-10T19:24:53Z (GMT). No. of bitstreams: 1 Franciele_texto.pdf: 972546 bytes, checksum: 4159555de632249d0c83764a3aecc74c (MD5) Previous issue date: 2011-07-07 / Studies on spatial variability of soybeans yield are of great importance for the development of new technologies that improve the world agricultural production. One of methods that allows this study is geostatistics. The geostatistical analysis makes possible the predictions of results and one of its products are thematic maps. Thus, this trial describes some techniques to draw and compare thematic maps using kriging. The analysis was based on data from soybean yield in t ha−1 according to harvest year 2004/2005 in an experimental area with sampling grades whose distances were: 25x25 m, 50x50 m, 75x75 m and 100x100 m plus a harvest monitor. The maps were compared using error matrix and confusion matrix. In addition, there was a better accuracy of the spatial variability maps that were drawn, while the analysis of coefficients of accuracy allows a better planning of sampling mesh for future studies. The measures of accuracy that were obtained by error matrix are significant options to make comparison among thematic maps, once they provide global indices and also by classes. / Com o aumento da produção agrícola mundial, o processo de produção agrícola tornou-se alvo do estudo de diversos pesquisadores. Estudos sobre a variabilidade espacial da produtividade da soja são de grande importância para o desenvolvimento de novas tecnologias, que beneficiam a agricultura. A análise geoestatística torna possível realizar previsões dos resultados, tendo como um de seus produtos os mapas temáticos. Este trabalho descreve algumas técnicas para a construção e comparação de mapas temáticos, utilizando a krigagem. A análise foi realizada com dados da produtividade de soja em t ha−1 do ano agrícola 2004/2005 numa área experimental com grades de amostragem com distâncias de 25x25 m, 50x50 m, 75x75 m, 100x100 m e monitor de colheita, comparando-se os mapas, utilizando a matriz de erros e a matriz de confusão. Além de uma melhor precisão dos mapas de variabilidade espacial gerados, a análise dos índices de acurácia possibilita um melhor planejamento das malhas amostrais para futuros estudos. As medidas de acurácia obtidas por meio da matriz de erros são opções significativas para realizar a comparação entre mapas temáticos, uma vez que fornecem índices globais e também por classes.
374

Análise geoestatística de mapas temáticos da produtividade da soja com diferentes grades amostrais / Geostatistical analysis of thematic maps of soybean yield with differente sampling grids

Kestring, Franciele Buss Frescki 07 July 2011 (has links)
Made available in DSpace on 2017-05-12T14:48:16Z (GMT). No. of bitstreams: 1 Franciele_texto.pdf: 972546 bytes, checksum: 4159555de632249d0c83764a3aecc74c (MD5) Previous issue date: 2011-07-07 / Studies on spatial variability of soybeans yield are of great importance for the development of new technologies that improve the world agricultural production. One of methods that allows this study is geostatistics. The geostatistical analysis makes possible the predictions of results and one of its products are thematic maps. Thus, this trial describes some techniques to draw and compare thematic maps using kriging. The analysis was based on data from soybean yield in t ha−1 according to harvest year 2004/2005 in an experimental area with sampling grades whose distances were: 25x25 m, 50x50 m, 75x75 m and 100x100 m plus a harvest monitor. The maps were compared using error matrix and confusion matrix. In addition, there was a better accuracy of the spatial variability maps that were drawn, while the analysis of coefficients of accuracy allows a better planning of sampling mesh for future studies. The measures of accuracy that were obtained by error matrix are significant options to make comparison among thematic maps, once they provide global indices and also by classes. / Com o aumento da produção agrícola mundial, o processo de produção agrícola tornou-se alvo do estudo de diversos pesquisadores. Estudos sobre a variabilidade espacial da produtividade da soja são de grande importância para o desenvolvimento de novas tecnologias, que beneficiam a agricultura. A análise geoestatística torna possível realizar previsões dos resultados, tendo como um de seus produtos os mapas temáticos. Este trabalho descreve algumas técnicas para a construção e comparação de mapas temáticos, utilizando a krigagem. A análise foi realizada com dados da produtividade de soja em t ha−1 do ano agrícola 2004/2005 numa área experimental com grades de amostragem com distâncias de 25x25 m, 50x50 m, 75x75 m, 100x100 m e monitor de colheita, comparando-se os mapas, utilizando a matriz de erros e a matriz de confusão. Além de uma melhor precisão dos mapas de variabilidade espacial gerados, a análise dos índices de acurácia possibilita um melhor planejamento das malhas amostrais para futuros estudos. As medidas de acurácia obtidas por meio da matriz de erros são opções significativas para realizar a comparação entre mapas temáticos, uma vez que fornecem índices globais e também por classes.
375

Runge-Kutta type methods for differential-algebraic equations in mechanics

Small, Scott Joseph 01 May 2011 (has links)
Differential-algebraic equations (DAEs) consist of mixed systems of ordinary differential equations (ODEs) coupled with linear or nonlinear equations. Such systems may be viewed as ODEs with integral curves lying in a manifold. DAEs appear frequently in applications such as classical mechanics and electrical circuits. This thesis concentrates on systems of index 2, originally index 3, and mixed index 2 and 3. Fast and efficient numerical solvers for DAEs are highly desirable for finding solutions. We focus primarily on the class of Gauss-Lobatto SPARK methods. However, we also introduce an extension to methods proposed by Murua for solving index 2 systems to systems of mixed index 2 and 3. An analysis of these methods is also presented in this thesis. We examine the existence and uniqueness of the proposed numerical solutions, the influence of perturbations, and the local error and global convergence of the methods. When applied to index 2 DAEs, SPARK methods are shown to be equivalent to a class of collocation type methods. When applied to originally index 3 and mixed index 2 and 3 DAEs, they are equivalent to a class of discontinuous collocation methods. Using these equivalences, (s,s)--Gauss-Lobatto SPARK methods can be shown to be superconvergent of order 2s. Symplectic SPARK methods applied to Hamiltonian systems with holonomic constraints preserve well the total energy of the system. This follows from a backward error analysis approach. SPARK methods and our proposed EMPRK methods are shown to be Lagrange-d'Alembert integrators. This thesis also presents some numerical results for Gauss-Lobatto SPARK and EMPRK methods. A few problems from mechanics are considered.
376

Some branching rules for GL(N,C)

Hall, Jack Kingsbury, Mathematics & Statistics, Faculty of Science, UNSW January 2007 (has links)
This thesis considers symmetric functions and algebraic combinatorics via the polynomial representation theory of GL(N,C). In particular, we utilise the theory of Jacobi-Trudi determinants to prove some new results pertaining to the Littlewood-Richardson coefficients. Our results imply, under some hypotheses on the strictness of the partition an equality between Littlewood-Richardson coefficients and Kostka numbers. For the case that a suitable partition has two rows, an explicit formula is then obtained for the Littlewood-Richardson coefficient using the Hook Length formula. All these results are then applied to compute branching laws for GL(m+n,C) restricting to GL(m,C) x GL(n,C). The technique also implies the well-known Racah formula.
377

Étude de l'effet de taille et de structure sur l'élasticité de composites W/Cu nanostructurés en couche mince

Girault, Baptiste 30 September 2008 (has links) (PDF)
Les lois régissant le comportement mécanique des matériaux cristallins présente une forte dépendance à la microstructure de ces derniers, et notamment, à la taille des cristallites lorsqu'ils atteignent l'échelle nanométrique. Le contrôle de la structuration des échantillons est assuré par la stratification de matériaux immiscibles, tungstène et cuivre, de réponse mécanique élastiquement isotrope et anisotrope, respectivement. La caractérisation des films réalisés par dépôts en phase vapeur a été réalisée par analyse combinée de clichés de microscopie électronique et données de diffraction et diffusion des rayons X. L'instrumentation alors mise en oeuvre afin d'accéder à la réponse élastique est la traction in situ de films minces de type composite W/Cu supportés, couplée à la diffraction des rayons X. Ce travail de recherche témoigne de la forte complémentarité entre les caractérisations microstructurales de microscopie électronique et de diffraction des rayons X, nécessaires à l'interprétation des résultats des essais de traction in situ, notamment en termes de modélisation. Il a ainsi pu être mis en évidence le caractère dispersoïde des fines couches de cuivre déposées et ainsi qu'une répartition particulière des orientations préférentielles au sein des couches de tungstène, <110> et <111>. Les résultats obtenus sur composites W/Cu à dispersoïdes quasi-isotrope de cuivre et lamellaires ont très clairement révélé un effet de structure et de taille sur les sous-couches de tungstène. Une étude plus approfondie du domaine élastique au sein de composites lamellaires a non seulement révélé que son étendue présentait une forte dépendance aux contraintes résiduelles, mais aussi que l'apparition des dislocations au sein des couches de cuivre entraînait un transfert de charge vers les couches de tungstène, conduisant à la fissuration en mode II.
378

Analyse des séries chronologiques à mémoire longue dans le domaine des ondelettes

Kouamo, Olaf 28 January 2011 (has links) (PDF)
Le thème de nos travaux porte sur la statistique des processus à longue mémoire, pour lesquels nous proposons et validons des outils statistiques issus de l'analyse par ondelettes. Ces dernières années ces méthodes pour estimer le paramètre de mémoire sont devenues très populaires. Cependant, les résultats théoriques validant rigoureusement les estimateurs pour les modèles semi paramétriques classiques à longue mémoire sont récents (cf. les articles de E. Moulines, F. Roueff et M. Taqqu depuis 2007). Les résultats que nous proposons dans cette thèse s'inscrivent directement dans le prolongement de ces travaux. Nous avons proposé une procédure de test pour détecter des ruptures sur la densité spectrale généralisée. Dans le domaine des ondelettes, le test devient un test de ruptures sur la variance des coefficients d'ondelettes. Nous avons ensuite développé un algorithme de calcul rapide de la matrice de covariance des coefficients d'ondelettes. Deux applications de cet algorithme sont proposées , d'une part pour l'estimation de d et d'autre part pour améliorer le test proposé dans le chapitre précédent. Pour finir, nous avons étudié les estimateurs robustes robustes du paramètre de mémoire d dans le domaine des ondelettes. en se basant sur trois estimateurs de la variance des coefficients d'ondelettes à une échelle. La contribution majeure de ce chapitre est le théorème central limite obtenu pour les trois estimateurs de d dans le cadre des processus gaussiens M(d).
379

Establishing low-energy x-ray fields and determining operational dose equivalent conversion coefficients

Larsson, Ylva January 2008 (has links)
<p>Reference radiation fields for x-ray qualities are described by the International Organization of Standards (ISO). This study describes the procedure to establish nine different low energy X-ray qualities at the national metrology laboratory, Swedish Radiation Protection Authority, following the document ISO 4037. Measurements of tube voltage, half-value layer, mean energy and spectral resolution have been performed for qualities N-15, N-20, N-25, N-30, N-40, L-20, L-30, L-35 and L-55. Furthermore, dose equivalent conversion coefficients for operational quantities ambient dose equivalent, personal dose equivalent and directional dose equivalent have been calculated by folding the mono-energetic conversion factors with measured spectral distributions of the x-ray qualities. The spectral distributions were unfolded from pulse-height distributions to photon distributions using simulated data of the semi-conductor detector used for measurements, generated with the Monte Carlo code PENELOPE.</p>
380

Schémas Volumes Finis en mécanique des fluides complexes

Krell, Stella 08 September 2010 (has links) (PDF)
Le travail de thèse exposé dans ce manuscrit porte sur le développement et l'analyse numérique de schémas volumes finis de type dualité discrète (DDFV) pour la discrétisation des équations de Darcy et des équations de Stokes. Un point commun à ces problèmes, qui motive l'emploi des schémas DDFV, est que leur résolution par volumes finis nécessite d'approcher toutes les composantes du gradient de la solution. On étudie tout d'abord la discrétisation du problème de diffusion scalaire anisotrope pour des conditions aux bords mixtes de type Dirichlet/Fourier. Le schéma que nous proposons permet de construire un algorithme de Schwarz discret associé à une décomposition de domaine sans recouvrement qui converge vers la solution obtenue sans décomposition. Des expériences numériques illustrent les résultats théoriques d'estimation d'erreur et de convergence des algorithmes de Schwarz DDFV. On se propose ensuite de discrétiser des problèmes de Stokes avec une viscosité variable. Les schémas DDFV correspondant sont en général mal posés. Pour y remédier, on stabilise le bilan de masse par différents termes en pression. Dans un second temps, on considère le cas où la viscosité est discontinue. Ces discontinuités doivent être prise en compte par le schéma pour surmonter la perte de consistance des contraintes à l'interface. Ensuite une première étude de l'extension des schémas DDFV aux équations de Navier-Stokes est présentée aussi qu'une généralisation des résultats pour le problème de Stokes avec une viscosité régulière dans le cas tridimensionnel.

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