The objective of this research is a fast circular synthetic aperture radar (F-CSAR) algorithm. Slow-time imaging distinguishes synthetic aperture radar (SAR) from its predecessor imaging radars. SAR slow-time imaging is strongly rooted in Huygens-Fresnel principle and Kirchhoff's approximation based scalar diffraction theory. Slant-plane SAR Green's function and resultant Fourier integral, unlike some Fourier integrals, cannot be analyzed using residue theory from complex analysis and Cauchy-Riemann equations yield analyticity. The asymptotic expansion of 1D and 2D Fourier integrals renders a decomposition of the Green's function leading to SAR data focusing. The research unveils Fraunhofer diffraction patterns in 2D aperture synthesis formulation corresponding to various aperture shapes including circular aperture that appears to be an optimum aperture shape from the mathematical condition in the asymptotic expansion. It is shown that these diffraction patterns may be used for refocusing of defocused images. F-CSAR algorithm is demonstrated using Householder transform recently shown to have improved error bounds and stability. Research is also carried out into various interpolation schemes. Backprojection implementation of CSAR is compared to F-CSAR and elevation coverage renders 3D reconstruction. F-CSAR is also demonstrated using GTRI T-72 tank turntable data.

Dissertation (Ph.D.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references (p.111-117).

Modern embedded systems complexity, performance and energy efficiency has been increasing steeply the last few years. An explosive growth in demand for wireless communication is observed as well and modern wireless links are expected to deliver bit rates of several gigabits while consuming even less energy. In order to satisfy these needs new technologies emerge and novel design approaches are put into practice. Communication at 60 GHz is such a technology that is able to deliver high bit rates in short range wireless links. A major motivation to use the 60 GHz spectrum is the worldwide availability which makes exploitation economically viable. Moreover, small wavelength of only 5 mm promises high integration due to small antenna component size which is one of the main bottlenecks for reducing the dimensions. However, increased frequency comes with many disadvantages as well. To increase the market potential of such a new technology the chip design needs to be cheap and energy-efficient. Such cost and energy constrains heavily impact the performance and the quality of both the analog and the digital components of the chip. In the current thesis the design possibilities of a component in the digital baseband of the receiver of such a chip are explored. The component under investigation is a Fast Fourier Transform (FFT) that is used for frequency domain equalization. This part of the receiver is used to reduce the effects of multipath in a non line-ofsight communication environment and as this is a common case in wireless communication the FFT block has been identified as one of the 2 most computational intensive components of the receiver in 60 GHz. This is the main reason why we explore possibilities to further decrease the power consumption of the block while maintaining the performance and the quality of service. To achieve this reduction the possibilities of a new design concept are explored. System Scenarios is a new design concept for embedded systems operating in dynamic environments. Wireless communication systems exhibit high dynamism during their operation on highly varying data streams, providing the System Scenarios huge xvi capabilities. The essential idea behind system scenarios is the classification of the application under investigation from a cost perspective during design time. Then, the classification is exploited during run time resulting to an overall improved implementation of the application. To achieve this the application is broken down to run-time situations (RTS) which are distinguishable operation modes of the application. Then RTSs with similar costs are clustered to form system scenarios. Finally for each scenario a different mapping and scheduling of the application is generated. In the case of the current thesis the application is the FFT and the cost perspective is the power consumption of the component. To exploit the RTS clustering in run time different quantization schemes have been produced. These schemes have been generated based on various properties of the data waveforms in the input of the FFT. The thesis explores the potential of the System Scenarios as well as the application of a quantization methodology for the FFT. Different options of the RTS clustering and the quantization of the FFT block are evaluated in order to come up with a more efficient implementation. / Τα σύγχρονα ηλεκτρονικά συστήματα παρέχουν στους χρήστες έναν καθημερινά αυξανόμενο αριθμό υπηρεσιών και λειτουργιών. Η ζήτηση τς αγοράς για ϕθηνές, αξιόπιστες και ϕορητές ηλεκτρονικές συ- σκευές ωθεί τα όρια του σχεδιασμού των ενσωματωμένων συστημάτων σε νέες ανεξερεύνητες περιοχές. Η ϕορητότητα απαιτεί την αϕαίρεση όλων των καλωδίων είτε για μετάδοση δεδομένων είτε για ενέργεια. Για να επιτευχθεί αυτό, η ασύρματη επικοινωνία σε υψηλό ρυθμό μετάδοσης είναι επιθυμητή χωρίς να θυσιαστεί η υψηλή ενεργειακή απο- δοτικότητα που καθιστά την συσκευή αυτόνομη από το ενεργειακό δίκτυο για μεγάλες χρονικές περιόδους. Η συνεχής αύξηση στις προδιαγραϕές των σύγχρονων ενσωματομένων συστημάτων έχει οδηγήσει στην χρήση καινοτόμων ιδεών, προσεγγίσεων και τεχνολογιών. Μια νέα τεχνολογία που υπόσχεται υψηλή ολοκλήρωση και υψηλό ρυθμό μετάδοσης δεδομένων στις ασύρματες ζεύξεις είναι η επικοινωνία στα 60 GHz. Μια νέα προσέγγιση σχεδιασμού για ενσωματομένα συστήματα υπόσχεται αποτελεσματική εκμετάλευση του δυναμισμού που μπορεί να παρουσιάζει ένα σύστημα. Τα ασύρματα συστήματα επικοινωνίας λειτουργούν τυπικά σε πολύ δυναμικά περιβάλλοντα. Τα Σενάρια συστήματος έχουν μεγάλες δυνατότητες για να βελτιώσουν την αποτελεσματικότητα της υλοποίησης των ψηϕιακών βάσεων τέτοιων συστημάτων. Στην παρούσα διπλωματική εξερευνούμε της δυνατότητες της αρχιτεκτονικής του FFT που βρίσκεται στην πλευρά του δέκτη ενός πομποδέκτη στα 60 GHz. Ο FFT είναι μέρος της εξίσωσης στο πεδίο της συχνότητας που χρησιμοποιείται για να μειώσει της επιδράσεις του ϕαινομένου multipath. Χρησιμοποιώντας Σενάρια Συστήματος προσπαθούμε να καταλήξουμε με μια πιο προσαρμοστική και συνεπώς πιο ενεργειακά αποδοτική υλοποίηση του μετασχηματισμού. Η εϕαρμογή των Σεναρίων Συστήματος χρησιμοποιώντας δεδομένα ως παράμετρο είναι μια καινοτόμα προσέγγιση και σε αυτή την διπλωματική εργασία ελέγχουμε την επιτευξιμότητα της. Για να επιτύχουμε κάτι τέτοιο πρέπει να μπορούμε να παράγουμε πολλαπλά διαϕορετικά σχέδια κβαντοποίησης του μετασχηματισμού σε αποδεκτά χρονικά διαστήματα. Οι παρούσες μέθοδοι κβαντοποίησης δεν μπορούν ακόμα να παρέχουν τέτοια δυνατότητα. Έτσι βασιζόμενοι στην επέκταση μια υπάρχουσας μεθοδολογίας προτείνουμε μια ολοκληρωμένη μεθοδολογία που μπορεί να παράγει σχέδια κβαντοποίησης μεγάλων στοιχείων υλικού όπως ο FFT.

Made available in DSpace on 2014-06-11T19:23:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-08-03Bitstream added on 2014-06-13T19:09:28Z : No. of bitstreams: 1 jasse_ff_me_arafo.pdf: 3143943 bytes, checksum: db74ccbc66112c4a240ca5402754512c (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Numerosos tipos e marcas comerciais de resinas compostas são constantemente introduzidos no mercado odontológico, em função de modificações na composição, tipo, formato e quantidade das partículas inorgânicas, assim como na porção orgânica. Sempre, com a finalidade de proporcionar propriedades mecânicas e estéticas superiores aos materiais, aumentando dessa forma sua longevidade. Assim, o propósito neste estudo foi avaliar o grau de conversão (GC) pelo método FT-IR e a degradação hidrolítica por meio do teste de dureza Vickers (dV), de duas resinas compostas (uma nanoparticulada e uma micro-híbrida). Para isso, oito espécimes (4 mm de diâmetro x 2 mm de espessura, ISO 4049) de cada material foram confeccionados para cada teste. As resinas compostas foram inseridas em única porção na matriz metálica e fotoativadas com aparelho LED (Celalux, Voco®, 776 mW/cm²), por 40 segundos. Dezesseis leituras de dV (8 no topo e 8 na base) foram realizadas para cada espécime em durômetro digital MMT-3 (Buehler Lake Bluff, Illinois USA), utilizando carga de 50 gf aplicada durante 30 segundos, em intervalos de tempo prédeterminados: imediatamente após fotoativação (controle), 24, 48, 72 horas, 7, 14, 21, 30 dias e 6 meses. Logo após a fotoativação foi feita a medida da dureza inicial e os espécimes foram então imersos em saliva artificial a 37°C. Para o GC (%), os espécimes foram triturados, prensados com KBr e analisados em espectrofotômetro FT-IR (Nexus-470). Os resultados foram submetidos à análise estatística e permitiram concluir que: não foi observada diferença entre as resinas quanto ao grau de conversão; a proporção entre as medidas de dureza de topo e base foi semelhante para os dois materiais, tendo sido mantida ao longo de todo o tempo experimental; a resina Z-250 apresentou os maiores valores de dureza tanto na superfície de topo quanto na de base... / Numerous types and brands of composite resins are constantly introduced into the dental market, due to changes in the composition, type, shape and quantity of inorganic particles as well as the organic portion. Always with the aim of providing superior mechanical and aesthetic properties to materials, thereby increasing their longevity. Thus, the purpose of this study was to evaluate the degree of conversion (DC) and hydrolytic degradation through the Vickers hardness test (hV) of two composites (a nanofilled and a microhybrid). For this, eight specimens (4 mm diameter x 2 mm thick, ISO 4049) of each material were prepared for each test. The composites were inserted into single increment in the metallic matrix and photoactivated with a LED unit (Celalux, Voco ®, 776 mW / cm ²) for 40 seconds. Sixteen hV readings (8 on each top and bottom surfaces) were performed for each specimen in MMT-3 digital hardness tester (Buehler Lake Bluff, Illinois USA), using load of 50 gf applied for 30 seconds, at predetermined intervals: immediately after polymerization (control), 24, 48, 72 hours, 7, 14, 21, 30 days and 6 months. After curing, initial hardness measurements were performed and the specimens were immersed in artificial saliva at 37 °C. For the DC (%), the specimens were ground, pressed with KBr and analyzed by FT-IR spectrophotometer (Nexus-470). The results were subjected to statistical analysis and concluded that: there was no difference between the resins for degree of conversion; the ratio between top and bottom hardness values was similar for both materials and was maintained throughout the experimental period; the composite resin Z-250 showed the highest hardness values in both the top surface as the bottom throughout the evaluation period. The materials tested showed no evidence of hydrolytic degradation in a significant way, in a six-month storage-time in artificial saliva

Submitted by PEDRO VALIM SAMPAIO null (pedrovalimsampaio@gmail.com) on 2018-01-11T01:06:31Z No. of bitstreams: 1 pedro-sampaio-dissertacao-pgmat-dezembro-2017-com-ficha.pdf: 8235020 bytes, checksum: 58adc9b07110ff0e572b49fd9bc15579 (MD5) / Rejected by Marcia Correa Bueno Degasperi null (mcbueno@rc.unesp.br), reason: Prezado Pedro Valim Sampaio, Solicitamos que realize uma nova submissão seguindo as orientações abaixo: - capa (faltou a capa que é elemento obrigatório no seu programa de pós-graduação. Agradecemos a compreensão e aguardamos o envio do novo arquivo. Atenciosamente, Biblioteca câmpus Rio Claro Repositório institucional Unesp on 2018-01-11T12:47:44Z (GMT) / Submitted by PEDRO VALIM SAMPAIO null (pedrovalimsampaio@gmail.com) on 2018-01-11T13:35:32Z No. of bitstreams: 2 pedro-sampaio-dissertacao-pgmat-dezembro-2017-com-ficha.pdf: 8235020 bytes, checksum: 58adc9b07110ff0e572b49fd9bc15579 (MD5) pedro-sampaio-dissertacao-pgmat-dezembro-2017-com-ficha-e-capa.pdf: 8377820 bytes, checksum: 3d6af025594125f81c9f43dc70d7b7f8 (MD5) / Approved for entry into archive by Adriana Aparecida Puerta null (dripuerta@rc.unesp.br) on 2018-01-11T16:45:12Z (GMT) No. of bitstreams: 1 sampaio_pv_me_rcla.pdf: 8271293 bytes, checksum: 10bf9858fb1a38ce127cb3c9b992f9df (MD5) / Made available in DSpace on 2018-01-11T16:45:12Z (GMT). No. of bitstreams: 1 sampaio_pv_me_rcla.pdf: 8271293 bytes, checksum: 10bf9858fb1a38ce127cb3c9b992f9df (MD5) Previous issue date: 2017-12-18 / Esta dissertação explora fundamentos comuns de dois temas, Música e Matemática, que são desenvolvidos lado a lado. Noções musicais e matemáticas são reunidas, como escalas e aritmética modular, intervalos e logaritmos, música de doze tons e aritmética modular, timbre e análise de Fourier. Quando possível, as discussões de noções musicais e matemáticas estão diretamente interligadas. Ocasionalmente o texto permanece por um tempo sobre um assunto e não sobre o outro, mas finalmente a conexão é estabelecida, tornando este um tratamento integrador dos dois assuntos. É uma tradução matematicamente comentada de uma grande parte de Mathematics and Music de David Wright. / This dissertation explores the common foundations of the two subjects, Music and Mathematics, which are developed side by side. Musical and mathematical notions are brought together, such as scales and modular arithmetic, intervals and logarithms, twelve tone music and modular arithmetic, timbre and Fourier analysis. When possible, discussions of musical and mathematical notions are directly interwoven. Occasionally the text stays for a while on one subject and not the other, but eventually the connection is established, making this an integrative treatment of the two subjects. It is a mathematically commented translation (to portuguese) of a major part of David Wright’s Mathematics and Music.

Le but de ce travail de thèse est de doter la métrologie française d'un instrument de référence dédié à la caractérisation métrologique des propriétés réflectives des objets qui, du point de vue de l'apparence, sont à l'origine des sensations de couleur, de brillant, de texture, de translucidité…etc. Ce mémoire décrit la conception, réalisation et mise au point d'un dispositif de mesure de la fonction de distribution bidirectionnelle du facteur de luminance d'une surface plane (BRDF). La BRDF est la grandeur physique qui caractérise intégralement la réflexion lumineuse à la surface d'un matériau. En cela, sa mesure s'inscrit comme un outil indispensable pour la mesure de l'apparence car elle permet de connaître en détail le signal qui entre dans l'œil.Certaines surfaces présentent une apparence pigmentée, métallisée, nacrée ou encore interférentielle, ces surfaces, dites "goniochromatiques", ont la capacité de changer d'apparence en fonction de l'angle d'observation. Pour les caractériser, il est impératif d'effectuer une mesure de BRDF sous plusieurs conditions d'observation et d'illumination. L'outil de mesure de la BRDF est un gonioréflectomètre, dédié à des mesures dans le domaine UV - Visible (250 nm – 900 nm).Le montage expérimental consiste en deux lignes distinctes. La première, appelée voie spectrale, est dédiée à l'étude de la couleur. Elle est constituée d'une illumination fixe assurée par une lampe à décharge de xénon filtrée par un monochromateur puis focalisée sur la surface étudiée. La détection, mobile, est assurée par un système optique constitué de lentilles et de miroirs qui servent à renvoyer la lumière réfléchie par la surface sur la photodiode.La deuxième ligne, appelée voie spatiale, est la dédiée à l'étude du brillant. Elle requière une résolution angulaire qui égale l'acuité visuelle de l'œil humain (0,03°) c'est cette partie qui introduit l'originalité de notre instrument. Sur cette voie, la détection est fixe et est basée sur la combinaison d'une optique de Fourier et d'une caméra CCD (512x512 pixels). L'illumination est mobile et est assurée par une lampe incandescente à filament de tungstène collimatée sur l'échantillon.Les deux lignes partagent un robot porte-échantillon qui offre six dégrées de liberté qui sert à reproduire toutes les directions d'illumination et d'observation au-dessus de l'échantillon.Mots clés : Couleur, Brillant, BRDF, Goniochromatisme, Pic spéculaire. / The aim of this thesis is to provide the French Metrology with a reference instrument that can be used for measuring the appearance of objects. Several physical properties of object appearance are used not only to identify the object itself but also determine its quality. These include color, gloss, texture and translucency. This work describes the design, characterization and the implementation of an instrument that has been built particularly to measure the bidirectional reflectance distribution function (BRDF) of planar surfaces. BRDF is a physical quantity that enables measuring the surface color and gloss. Accordingly it is important to ensure accurate and traceable measurements of such a quantity in order for a comprehensive understanding of surface properties to be fulfilled.Some surfaces show pigmented, metallic, sparkling or pearlescent appearance. These surfaces, called goniochromatic surfaces, have the ability to change their appearance depending on the viewing angle. To characterize them, it is necessary to deliver surface reflectance measurements at several directions and under different illumination conditions. The instrument that enables these measurements is called gonioreflectometer.The experimental setup we have designed consists of two separate detection lines. The first line, called "color line", is used to study the color. It consists of a stationary illumination source that uses a xenon lamp spectrally resolved by a monochromator. The light coming out from the source is focused on the surface under investigation. The reflected light by the surface is collected by using a lens and directed onto a photodiode by a mirror. This detection system can be moved over a wide angular range so as to measure the BRDF.The second line, called "gloss line", is used to measure the gloss of the surface. In order to be very close to the average human observer, high angular resolution is required. In this line the detection part is stationary. It consists of a Charged Coupled Device (CCD) camera of 512 x 512 pixels. The source used to illuminate the surface is an incandescent tungsten lamp. Angular measurements in this line are provided by the movement of the illumination source itself. Both color and gloss lines share a robot sample-holder that provides six degrees of freedom. This of course facilitates measurements over varies detection and illumination directions of the sample.Key words: Color, Gloss, BRDF, Goniochromatisme, Specular pic.

Ce travail propose de nouvelles contributions aux méthodes d’homogénéisation avec des applications aux composite, aux polycristaux et aux milieux poreux. Les propriétés effectives sont déterminées en résolvant un problème élémentaire sur la cellule unitaire que l’on peut reformuler avec l’équation de Lippmann-Schwinger (LS). Celle-ci est résolue en utilisant des développements en série de Neumann. Plusieurs approches sont alors proposées pour calculer les différents termes de la série, en utilisant des approches analytiques ou numériques. Ainsi, dans les deux premiers chapitres, on établit une famille d’équation LS pour la polarisation dans le contexte de la conductivité thermique et de l’élasticité. L’opérateur de cette équation est optimisé afin d’obtenir la meilleur convergence de la série de Neumann et par conséquent la meilleur estimation des propriétés effectives du composite. L’estimation proposée est basée à la fois sur une série tronquée et une estimation du résidu de la série de Neumann. Le travail présenté au chapitre 3 concerne le calcul des propriétés de transport de masse en milieu poreux. De manière classique, la loi de filtration est donnée par la loi de Darcy à l’échelle macroscopique. Dans ce travail, on calcule les termes correctifs à l’équation de Darcy lorsque la condition de stricte séparation des échelles n’est pas vérifiée. Ces termes correctifs sont calculés numériquement en résolvant une équation LS et en utilisant un schéma itératif basé sur la transformée de Fourier Rapide (TFR). Finalement, au chapitre 4, on détermine numériquement des bornes pour les propriétés élastiques des polycristaux en utilisant toujours les approches basées sur la TFR. L’approche proposée permet de tenir compte de la géométrie exacte de la cellule de Voronoi en utilisant les expressions exactes des fonctions formes pour des polygones et des polyèdres. La méthode est appliquée à des polycristaux constitués de monocristaux cubiques / This work proposed some contributions to the homogenization methods with applications to composites materials, polycristals and porous media. The effective properties are determined by solving the unit cell problem and the corresponding Lippmann-Schwinger (LS) equation. The latter is solved by means of Neumann series. Different approaches are considered to evaluate each terms of the series using analytic or numerical approaches. In the first two chapters, we formulate a general class of LS equations for the polarization in the case of conductivity and then elasticity. The operator of the latter is optimized to obtain the best convergence of the associated Neumann series and then of the better estimate of the effective of the composite. The estimate is based on both a truncated Neumann series and an approximation of its residual. In chapter 3, we deal with the mass transport properties of porous media. Classically, the filtration law is given by the Darcy equation at the macroscopic scale. In the present work we compute the corrective terms of the Darcy equation in the situation of no strict scale separation. These corrective terms are determined numerically by solving a LS equation with a fast Fourier Transform (FFT) based iterative scheme. Finally, in chapter 4, we derivative numerically some bounds for the elastic properties of polycristals still by means of an FFT iterative scheme. The approach uses an exact description of the voronoi-unit cell geometry by using the shape functions of polygons and polyhedrons. The method is applied to polycristals constituted of cubic single crystals

Cette thèse présente une extension de l'analyse fréquentielle des light-fields locaux de Durand et al. [2005]. Nous proposons l'étude de phénomènes de transport radiatif tels que la réfraction par des surfaces non-spéculaires, les effets de flou de bougé et la diffusion de la lumière dans les volumes tels que les nuages. Nous proposons de plus une extension de l'état de l'art en analyse fréquentielle avec l'ajout de l'étude de l'occlusion non-planaire, des SVBRDFs anisotropes ainsi que les systèmes de lentilles. Dans ce cadre, nous présentons l'analyse de la matrice covariance de l'amplitude du spectre, un outil compact d'analyse et compatible avec les méthodes statistiques d'intégrations. Nous montrons l'utilité de cet outil avec différentes applications: le sampling adaptatif avec reconstruction des effets de flou de profondeur et de bougé, l'estimation de noyaux de reconstructions pour l'algorithme de photon mapping et le sampling adaptatif des effets volumiques. / This thesis presents an improvement over the frequency analysis of local light-fields introduced by Durand et al. in 2005. We add into this analysis of light transport operations such as rough refractions, motion effects and scattering in participating media. We further improve the analysis by updating previously proposed operations to handle non-planar occlusions of light, spatially-varying anisotropic BRDFs and multiple lenses. We present the covariance analysis of light transport, a method to estimate the covariance matrix of a local light-field from the set of operations it undergoes. We show the use of such tool with various applications ranging from motion blur and depth-of-field adaptive sampling and filtering, photon mapping kernel size estimation and adaptive sampling of volumetric effects.

[pt] A geração de cenas realísticas de fenômenos naturais em tempo real é uma das mais importantes áreas de pesquisa para aplicações em jogos e simuladores. No início da computação gráfica para tempo real, a maioria das aplicações tratava a superfície da água como um plano com uma textura. Essa abordagem produz uma visualizaçãomuito pouco realística da superfície da água, além de não reproduzir o comportamento hidrodinâmico correto da água. Nesse contexto, muitos grupos de pesquisa desenvolveram técnicas para a visualização realística da superfície da água, contudo, a maioria desses trabalhos foca no processo off-line e poucos tratam da questão em tempo real. No entanto, os recentes avanços no desempenho do hardware permitiram a utilização de técnicas tradicionalmente usadas emoff-line para o escopo de tempo real, porém não há uma pesquisa-guia que descreva tais técnicas e faça uma análise comparativa das mesmas. Sendo assim, sem tal pesquisa-guia é muito difícil escolher a melhor técnica para um hardware específico ou se determinada técnica provê o controle de simulação necessário para uma aplicação específica.Nesse contexto, a presente pesquisa analisa as técnicas mais importantes para visualização e simulação de oceano em tempo real, utilizando a unidade de processamento gráfico como o processador principal. Além disso, ela realiza uma análise comparativa de desempenho de cada técnica e estuda os prós e contras delas. Ainda, alguns métodos off-line clássicos são adaptados para uso na GPU. / [en] The synthesis of realistic natural scenes in real time is one of the most important research areas for applications in games and simulators. In the beginning of real-time computer graphics, most of the applications treated water surface as a textured plane. This approach produces a very low realistic rendering of the water surface and does not reproduce the correct hydrodynamics behaviour of the water. So, a lot of research groups developed techniques for realistic water rendering, most of them for off-line processes and a few for real-time use. However, current improvementson hardware performance allow the usage oftraditional off-line techniques for real-time proposes, but there is no research work that describesthese techniques and makes a comparative analysis of them. Then, without this comparative analysis, it is very difficult to choose the best technique for a specific hardware or to decide if a particular technique provides the simulation control that a certain application needs.In this context, the present research work analyses the most important techniques for real-time ocean water simulation and visualization using the graphics processor unit as a main processor. Moreover, it makes a performance comparative analysis of each technique and analyses the pros and cons of them. Furthermore, some classic off-line methods are adapted for GPU use.

Made available in DSpace on 2014-06-11T19:26:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-08-25Bitstream added on 2014-06-13T20:27:11Z : No. of bitstreams: 1 carnierneto_d_me_rcla.pdf: 3759097 bytes, checksum: 779710eaadd918035376669c43711516 (MD5) / Esse trabalho apresenta os resultados obtidos com o monitoramento detalhado de nível d'água, realizado no período de 2002 a 2005 em poços no Aqüífero Rio Claro. Os problemas encontrados durante a coleta de dados dos poços de monitoramento foram solucionados por meio de programas desenvolvidos para este fim. Em seguida, os dados já tratados serviram à avaliação qualitativa dos fenômenos observados e comparados com aqueles encontrados na literatura. Por fim, foram aplicadas técnicas de análise de séries temporais (Análise de Fourier, Correlação Cruzada e Análise R/S) a esses dados, a fim de se verificar as periodicidades de alguns fenômenos naturais, como os ciclos sazonais e de maré terrestre, bem como estimar a relação temporal entre a pluviometria e a recarga, e avaliar o grau de persistência e auto-correlação das variações de nível d'água. Os resultados obtidos mostram que o monitoramento detalhado é capaz de fornecer informações que, além de contribuírem para um melhor conhecimento das características do aqüífero, podem auxiliar em processos de remediação, através da melhor caracterização da variação do nível d'água e seu conseqüente transporte vertical de contaminantes. / This work presents the results of detailed water level monitoring in the course of 2002 to 2005 in monitoring in wells on Rio Claro Aquifer. Problems found during data aquisition were solved by specific programs developed for this purpose. Qualitative evaluation of observed phenomena was made, comparing it with those from literature and, at the end, methods to time-series analysis were applied on data (Fourier Analysis, Cross-Correlation and R/S Analysis), in order to verify the periodicities of natural phenomena, like those resulting from seasonal cycles and earth-tides, to estimate temporal relationship between rainfall and well recovering, and evaluate the persistence and degree of auto-correlation of water levels variations. The results shows that detailed monitoring process gives important information that leads to a better knowledge on the aquifer characteristics, and it can help remediation process through a better characterization of water level variations and its consequent vertical transport of contaminants.