Orientadores: Jansle Vieira Rocha, Rubens Augusto Camargo Lamparelli / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-15T17:48:12Z (GMT). No. of bitstreams: 1 Figueiredo_GleyceKellyDantasAraujo_M.pdf: 6336572 bytes, checksum: 543d5ecd1cecff2ebb2ab13e845b5bfc (MD5) Previous issue date: 2010 / Resumo: A agricultura está fortemente ligada às condições meteorológicas, tornando-se uma atividade de risco. Sendo assim, um sistema de monitoramento e previsão de safras é necessário para evitar grandes perdas. O monitoramento agrícola, aliado a estudos de varibilidade meteorológica, é de extrema importância, pois determina a melhor época em que deve ocorrer a semeadura, bem como os períodos de maior necessidade hídrica da planta. A utilização do sensoriamento remoto para monitoramento agrícola e sua associação a dados meteorológicos viabilizam o monitoramento de culturas, desde o plantio até a colheita. Desta forma, o objetivo deste trabalho foi mapear culturas de verão (soja e milho) no estado do Paraná por meio de composições decendiais NDVI de imagens do satélite SPOT Vegetation nas safras 2005/2006, 2006/2007 e 2007/2008, e associar a dados de precipitação para determinar e mapear épocas de semeadura. Para isso, foi utilizado o método de classificação digital supervisionada em composições multitemporais das imagens, de forma a gerar máscaras da cultura da soja para cada composição decendial. A verificação da acurácia das máscaras foi realizada utilizando o índice Kappa alcançando valores de 0,70, 0,75 e 0,77, Exatidão Global 0,91, 0,91 e 0,93 e Índice de concordância de Willmot (d) entre 0,93, 0,93 e 0,99. Os perfis temporais de NDVI possibilitaram a detecção do início do ciclo vegetativo das culturas. Foram utilizados dados de precipitação da rede de estações meteorológicas do SIMEPAR e do modelo atmosférico ECMWF. Os dados das estações meteorológicas foram compilados a partir de dados diários a dados decendiais, tendo em vista que as informações do modelo são decendiais. Em seguida foi necessário especializá-las e reamostrá-las para um grid de 1 km x 1 km. Essas duas informações foram interpoladas através do Inverso Quadrado da Distância a fim de obter o perfil de precipitação da região estudada durante a safra de verão. A interpolação de dados de precipitação mostrou-se expressiva, uma vez que os valores interpolados e os valores reais foram significativos quando avaliado pelo índice de concordância 'd' de Willmot, variando entre 0,74 a 0,99. Para as três safras em estudo, apenas o comportamento da última foi distinta das demais, onde foi possível detectar atraso da chuva de um mês em relação às outras safras. Com a espacialização da precipitação dentro do estado foi possível fazer o cruzamento entre as máscaras da cultura de verão e os mapas de precipitação decendial, de modo a descobrir o inicio do desenvolvimento do ciclo da cultura. Desta forma foi possível perceber que houve um retardamento no início do ciclo da cultura para regiões em que a semeadura ocorreu antes do período mais chuvoso. A associação entre o perfil temporal de NDVI e precipitação permitiu identificar e mapear diferenças entre épocas de início de ciclo dentro do estado do Paraná / Abstract: Agriculture is highly dependent on meteorological conditions, making it a risky activity, so, in order to avoid large losses, it is necessary to devlop an appropriate crop yield forecasting system. Agricultural monitoring coupled with studies of weather variability is extremely important to determine the best time to sown as well as periods of higher water requirement by the plants. The use of remote sensing for agricultural monitoring in addition to meteorological data enables crop monitoring from planting to harvest. Thus, the goal of this study was to map summer crops in the state of Parana through dekadal composition of SPOT Vegetation NDVI imagery for the 2005/2006, 2006/2007 and 2007/2008 cropping seasons. Supervised classification of multitemporal image composites was used to generate cropland masks for each dekad. Accuracy assessment was performed using Kappa Index reaching values of 0.70, 0.75 and 0.77 and overall accuracy 0.91, 0.91 and 0.93. NDVI temporal profiles were used to detect the beginning of the crop vegetative cycles. Rainfall data from SIMEPAR network of meteorological ground stations and ECMWF atmospheric model were used. The data from the ground stations were compiled from daily to dekadal in order to comply with model data, which is a ten days compilation . Then it was necessary to spatialize and resample them to a 1 km x 1 km grid. These two data were interpolated using the inverse distance to square method to extract the profile of precipitation in the region during the summer harvesting season. The interpolation of rainfall generated good results, once the interpolated values as copared to actual values were significant when evaluated by the agreement index 'd' of Willmot, ranging between 0.74 to 0.99. For the three cropping seasons studied only the behavior of last season was distinct from the others , it was possible to detect a rain delay of one month in relation to other seasons. With the rainfall spacialization within the state it was possible to cross the masks of the summer crops with the maps of the decadal rainfall, in order to discover the beginning of the crop vegetative cycle. So it was possible to see that there was a delay at the beginning of the crop cycle in areas where the sowing occurred before the rainy season. The association between NDVI temporal profile and rainfall allowed to identify and to map the differences among starting of the crop vegetative cycle in the state of Parana / Mestrado / Planejamento e Desenvolvimento Rural Sustentável / Mestre em Engenharia Agrícola

O problema de reconstruir uma função f a partir de um número finito de valores conhecidos f(x0), f(x1), ..., f(xn) aparece com frequência em modelagem matemática. Em geral, não é possível determinar f completamente a partir de f(x0), f(x1), ..., f(xn), mas, em muitos casos de interesse, podemos encontrar aproximações razoáveis para f usando interpolação, que consiste em determinar uma função (um polinômio, ou uma função racional ou trigonométrica, etc) g que satisfaça g(xi) = f(xi); i = 0, 1, ..., n: Na prática, a função interpoladora g é avaliada em precisão finita e o valor final computado de g(x) pode diferir do valor exato g(x) devido a erros de arredondamento. Essa diferença pode, inclusive, ultrapassar o erro de interpolação E(x) = f(x) - g(x) em várias ordens de magnitude, comprometendo todo o processo de aproximação. A estabilidade numérica de um algoritmo reflete sua sensibilidade em relação a erros de arredondamento. Neste trabalho apresentamos uma análise detalhada da estabilidade numérica de alguns algoritmos utilizados no cálculo de interpoladores polinomiais ou racionais que podem ser postos na forma baricêntrica. Os principais resultados deste trabalho também estão disponíveis em língua inglesa nos artigos - Mascarenhas, W e Camargo, A. P., On the backward stability of the second barycentric formula for interpolation, Dolomites research notes on approximation v. 7 (2014) pp. 1-12. - Camargo, A. P., On the numerical stability of Floater-Hormann\'s rational interpolant, Numerical Algorithms, DOI 10.1007/s11075-015-0037-z. - Camargo, A. P., Erratum: On the numerical stability of Floater-Hormann\'s rational interpolant\", Numerical Algorithms, DOI 10.1007/s11075-015-0071-x. - Camargo, A. P. e Mascarenhas, W., The stability of extended Floater-Hormann interpolants, Numerische Mathematik, submetido. arXiv:1409.2808v5 / The problem of reconstructing a function f from a finite set of known values f(x0), f(x1), ..., f(xn) appears frequently in mathematical modeling. It is not possible, in general, to completely determine f from f(x0), f(x1), ..., f(xn) but, in several cases of interest, it is possible to find reasonable approximations for f by interpolation, which consists in finding a suitable function (a polynomial function, a rational or trigonometric function, etc.) g such that g(xi) = f(xi); i = 0, 1, ..., n: In practice, the interpolating function g is evaluated in finite precision and the final computed value of g(x) may differ from the exact value g(x) due to rounding. In fact, such difference can even exceed the interpolation error E(x) = f(x)-g(x) in several orders of magnitude, compromising the entire approximation process. The numerical stability of an algorithm reflect is sensibility with respect to rounding. In this work we present a detailed analysis of the numerical stability of some algorithms used to evaluate polynomial or rational interpolants which can be put in the barycentric format. The main results of this work are also available in english in the papers - Mascarenhas, W e Camargo, A. P., On the backward stability of the second barycentric formula for interpolation, Dolomites research notes on approximation v. 7 (2014) pp. 1-12. - Camargo, A. P., On the numerical stability of Floater-Hormann\'s rational interpolant, Numerical Algorithms, DOI 10.1007/s11075-015-0037-z. - Camargo, A. P., Erratum: On the numerical stability of Floater-Hormann\'s rational interpolant\", Numerical Algorithms, DOI 10.1007/s11075-015-0071-x. - Camargo, A. P. e Mascarenhas, W., The stability of extended Floater-Hormann interpolants, Numerische Mathematik, submetido. arXiv:1409.2808v5

[pt] O sistema SPEC (Speech Predictive Encoding Communication) é um método de redução de faixa que emprega técnicas de interpolação (digital) de voz. As diferenças entre os valores estimados e atuais das amostras do sinal de voz são comparadas, em um Processador, com um limiar, que pode ser fixo ou proveniente de uma tabela. O valor estimado utilizado na comparação é o do instante anterior, o que pode ser considerado como uma predição de ordem zero. O propósito principal deste trabalho é a investigação do efeito do uso de preditores de ordem superior para estimar amostras no sistema SPEC. Paralelamente, é investigado o desempenho do sistema com um Processador, no qual as diferenças entre os valores estimados e atuais das amostras são ordenadas de acordo com suas magnitudes. Assim, são transmitidas as amostras que correspondem às maiores diferenças não-comprimidas, diminuindo a degradação. / [en] The SPEC system (Speech Predictive Encoding Communication), is a bandwidth reduction method, which employs digital speech interpolation techniques. The differences between the estimated and present values of the samples of speech signals are compared, in a Processor, with a threshold which can be fixed or derived from a table. The estimated value used in the comparison is the one of the previous instant, which can be considered as a zero-order prediction. The main purpose of this work is the investigation of the effect of the use of higher order predictors to estimate samples in the SPEC system. At the same time, the system performance with a Processor where the differences between the estimated and the present values of the samples are ordered according to their magnitude is investigated. With this Processor, the samples corresponding to the greater non-compressed differences are transmitted, which contributes to minimize the system overload noise.

D.Phil. (Applied mathematics) / Please refer to full text to view abstract

The target of this master thesis is to evaluate the Image Warping technique and propose a possible design for an implementation in FPGA. The Image Warping is widely used in the image processing for image correction and rectification. A DSP is a usual choice for implantation of the image processing algorithms, but to decrease a cost of the target system it was proposed to use an FPGA for implementation. In this work a different Image Warping methods was evaluated in terms of performance, produced image quality, complexity and design size. Also, considering that it is not only Image Warping algorithm which will be implemented on the target system, it was important to estimate a possible memory bandwidth used by the proposed design. The evaluation was done by implemented a C-model of the proposed design with a finite datapath to simulate hardware implementation as close as possible.

The pseudospectral method is a family of numerical methods for the solution of differential equations based on the expansion of basis functions defined on a set of grid points. In this thesis, the relationship between the distribution of grid points and the accuracy and convergence of the solution is emphasized. The polynomial and sinc pseudospectral methods are extensively studied along with many applications to quantum and statistical mechanics involving the Fokker-Planck and Schroedinger equations. The grid points used in the polynomial methods coincide with the points of quadrature, which are defined by a set of polynomials orthogonal with respect to a weight function. The choice of the weight function plays an important role in the convergence of the solution. It is observed that rapid convergence is usually achieved when the weight function is chosen to be the square of the ground-state eigenfunction of the problem. The sinc method usually provides a slow convergence as the grid points are uniformly distributed regardless of the behaviour of the solution. For both polynomial and sinc methods, the convergence rate can be improved by redistributing the grid points to more appropriate positions through a transformation of coordinates. The transformation method discussed in this thesis preserves the orthogonality of the basis functions and provides simple expressions for the construction of discretized matrix operators. The convergence rate can be improved by several times in the evaluation of loosely bound eigenstates with an exponential or hyperbolic sine transformation. The transformation can be defined explicitly or implicitly. An explicit transformation is based on a predefined mapping function, while an implicit transformation is constructed by an appropriate set of grid points determined by the behaviour of the solution. The methodologies of these transformations are discussed with some applications to 1D and 2D problems. The implicit transformation is also used as a moving mesh method for the time-dependent Smoluchowski equation when a function with localized behaviour is used as the initial condition. / Science, Faculty of / Mathematics, Department of / Graduate

Orientador: Sérgio Antonio Tozoni / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação Científica / Made available in DSpace on 2018-08-22T06:19:51Z (GMT). No. of bitstreams: 1 Lopes_RaquelVieira_M.pdf: 1141005 bytes, checksum: 8091e673668abab031630ae7fd1b7436 (MD5) Previous issue date: 2013 / Resumo: Os sk-splines são uma generalização natural dos splines polinomiais, os quais foram introduzidos e tiveram sua teoria básica desenvolvida por Alexander Kushpel nos anos de 1983-1985. Estas funções são importantes em várias aplicações e seu espaço é gerado por translações discretas de uma única função núcleo. Neste trabalho, estudamos condições necessárias e suficientes para a existência e unicidade de sk-splines interpolantes de funções periódicas. Além disso, estudamos a aproximação de funções de determinadas classes por sk-splines nos espaços Lp. Como aplicação estudamos a aproximação de funções infinitamente diferenciáveis e finitamente diferenciáveis por sk- splines / Abstract: The sk-splines are a natural generalization of polynomial splines. They were introduced and their basic theory developed by Alexander Kushpel between 1983 and 1985. These functions are important in many applications and the space of sk-splines is the linear span of shifts of a single kernel K. In this work, we study necessary and sufficient conditions for the existence and uniqueness of sk-splines interpolants of periodic functions. Furthermore, we study the approximation in several classes of functions by sk-splines in the Lp spaces. As an application we study the approximation of infinitely and finitely differentiable functions by sk-splines / Mestrado / Matematica Aplicada / Mestra em Matemática Aplicada

The Reproducing Kernel Element Method (RKEM) is a hybrid between finite elements and meshfree methods that provides shape functions of arbitrary order and continuity yet retains the Kronecker-delta property. To achieve these properties, the underlying mesh must meet certain regularity constraints, unique to RKEM. The aim of this dissertation is to develop a precise definition of these constraints, and a general algorithm for assessing a mesh is developed. This check is a critical step in the use of RKEM in any application. The general checking algorithm is made more specific to apply to two-dimensional triangular meshes with circular supports and to three-dimensional tetrahedral meshes with spherical supports. The checking algorithm features the output of the uncovered regions that are used to develop a mesh-mending technique for fixing offending meshes. The specific check is used in conjunction with standard quality meshing techniques to produce meshes suitable for use with RKEM. The RKEM quasi-uniformity definitions enable the use of RKEM in solving Galerkin weak forms as well as in general interpolation applications, such as the representation of geometries. A procedure for determining a RKEM representation of discrete point sets is presented with results for surfaces in three-dimensions. This capability is important to the analysis of geometries such as patient-specific organs or other biological objects.

No description available.

In this thesis we survey several interpolation methods that are used to construct the yield curves. We also review the bootstrapping and show that the bootstrap is closely connected to the interpolation in the case of bootstrapping yield curve. The most effort is dedicated, in this thesis, on the monotone convex method and on investigation of the difficulties to get accurate yield curves.