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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.
141

Statistical Models of Market Reactions to Influential Trades

Guo, Yi-Ting 16 July 2007 (has links)
In this study, we consider high frequency transaction data of NYSE, and apply statistical methods to characterize each trade into two classes, influential and ordinary liquidity trades. First, a median based approach is used to establish a high R-square price-volume model for high frequency data. Next, transactions are classified into four states based on the trade price, trade volume, quotes, and quoted depth. Volume weighted transition probability of the four states are investigated and shown to be distinct for informed trades and ordinary liquidity trades. Furthermore, four market reaction factors are introduced and studied. Logistic regression models of the influential trades are established based on the four factors and odds ratios are used to select the cutoff points.
142

Modeling Diseases With Multiple Disease Characteristics: Comparison Of Models And Estimation Methods

Erdem, Munire Tugba 01 July 2011 (has links) (PDF)
Epidemiological data with disease characteristic information can be modelled in several ways. One way is taking each disease characteristic as a response and constructing binary or polytomous logistic regression model. Second way is using a new response which consists of disease subtypes created by cross-classification of disease characteristic levels, and then constructing polytomous logistic regression model. The former may be disadvantageous since any possible covariation between disease characteristics is neglected, whereas the latter can capture that covariation behaviour. However, cross-classifying the characteristic levels increases the number of categories of response, so that dimensionality problem in parameter space may occur in classical polytomous logistic regression model. A two staged polytomous logistic regression model overcomes that dimensionality problem. In this thesis, study is progressen in two main directions: simulation study and data analysis parts. In simulation study, models that capture the covariation behaviour are compared in terms of the response model parameter estimators. That is, performances of the maximum likelihood estimation (MLE) approach to classical polytomous logistic regression, Bayesian estimation approach to classical polytomous logistic regression and pseudo-conditional likelihood (PCL) estimation approach to two stage polytomous logistic regression are compared in terms of bias and variation of estimators. Results of the simulation study revealed that for small sized sample and small number of disease subtypes, PCL outperforms in terms of bias and variance. For medium scaled size of total disease subtypes situation when sample size is small, PCL performs better than MLE, however when the sample size gets larger MLE has better performance in terms of standard errors of estimates. In addition, sampling variance of PCL estimators of two stage model converges to asymptotic variance faster than the ML estimators of classical polytomous logistic regression model. In data analysis, etiologic heterogeneity in breast cancer subtypes of Turkish female cancer patients is investigated, and the superiority of the two stage polytomous logistic regression model over the classical polytomous logistic model with disease subtypes is represented in terms of the interpretation of parameters and convenience in hypothesis testing.
143

Relative Survival of Gags Mycteroperca microlepis Released Within a Recreational Hook-and-Line Fishery: Application of the Cox Regression Model to Control for Heterogeneity in a Large-Scale Mark-Recapture Study

Sauls, Beverly J. 01 January 2013 (has links)
The objectives of this study were to measure injuries and impairments directly observed from gags Mycteroperca microlepis caught and released within a large-scale recreational fishery, develop methods that may be used to rapidly assess the condition of reef fish discards, and estimate the total portion of discards in the fishery that suffer latent mortality. Fishery observers were placed on for-hire charter and headboat vessels operating in the Gulf of Mexico from June 2009 through December 2012 to directly observe reef fishes as they were caught by recreational anglers fishing with hook-and-line gear. Fish that were not retained by anglers were inspected and marked with conventional tags prior to release. Fish were released in multiple regions over a large geographic area throughout the year and over multiple years. The majority of recaptured fish were reported by recreational and commercial fishers, and fishing effort fluctuated both spatially and temporally over the course of this study in response to changes in recreational harvest restrictions and the Deepwater Horizon oil spill. Therefore, it could not be assumed that encounter probabilities were equal for all individual tagged fish in the population. Fish size and capture depth when fish were initially caught-and-released also varied among individuals in the study and potentially influenced recapture reporting probabilities. The Cox proportional hazards regression model was used to control for potential covariates on both the occurrence and timing of recapture reporting events so that relative survival among fish released in various conditions could be compared. A total of 3,954 gags were observed in this study, and the majority (77.26%) were released in good condition (condition category 1), defined as fish that immediately submerged without assistance from venting and had not suffered internal injuries from embedded hooks or visible damage to the gills. However, compared to gags caught in shallower depths, a greater proportion of gags caught and released from depths deeper than 30 meters were in fair or poor condition. Relative survival was significantly reduced (alpha (underline)<(/underline)0.05) for gags released in fair and poor condition after controlling for variable mark-recapture reporting rates for different sized discards among regions and across months and years when individual fish were initially captured, tagged and released. Gags released within the recreational fishery in fair and poor condition were 66.4% (95% C.I. 46.9 to 94.0%) and 50.6% (26.2 to 97.8%) as likely to be recaptured, respectively, as gags released in good condition. Overall discard mortality was calculated for gags released in all condition categories at ten meter depth intervals. There was a significant linear increase in estimated mortality from less than 15% (range of uncertainty, 0.1-25.2%) in shallow depths up to 30 meters, to 35.6% (5.6-55.7%) at depths greater than 70 meters (p < 0.001, R2 = 0.917). This analysis demonstrated the utility of the proportional hazards regression model for controlling for potential covariates on both the occurrence and timing of recapture events in a large-scale mark-recapture study and for detecting significant differences in the relative survival of fish released in various conditions measured under highly variable conditions within a large-scale fishery.
144

Predictions Within and Across Aquatic Systems using Statistical Methods and Models / Prediktioner inom och mellan akvatiska system med statistiska metoder och modeller

Dimberg, Peter H. January 2015 (has links)
Aquatic ecosystems are an essential source for life and, in many regions, are exploited to a degree which deteriorates their ecological status. Today, more than 50 % of the European lakes suffer from an ecological status which is unsatisfactory. Many of these lakes require abatement actions to improve their status, and mathematical models have a great potential to predict and evaluate different abatement actions and their outcome. Several statistical methods and models exist which can be used for these purposes; however, many of the models are not constructed using a sufficient amount or quality of data, are too complex to be used by most managers, or are too site specific. Therefore, the main aim of this thesis was to present different statistical methods and models which are easy to use by managers, are general, and provide insights for the development of similar methods and models. To reach the main aim of the thesis several different statistical and modelling procedures were investigated and applied, such as genetic programming (GP), multiple regression, Markov Chains, and finally, well-used criteria for the r2 and p-value for the development of a method to determine temporal-trends. The statistical methods and models were mainly based on the variables chlorophyll-a (chl-a) and total phosphorus (TP) concentrations, but some methods and models can be directly transferred to other variables. The main findings in this thesis were that multiple regressions overcome the performance of GP to predict summer chl-a concentrations and that multiple regressions can be used to generally describe the chl-a seasonality with TP summer concentrations and the latitude as independent variables. Also, it is possible to calculate probabilities, using Markov Chains, of exceeding certain chl-a concentrations in future months. Results showed that deep water concentrations were in general closely related to the surface water concentrations along with morphometric parameters; these independent variables can therefore be used in mass-balance models to estimate the mass in deep waters. A new statistical method was derived and applied to confirm whether variables have changed over time or not for cases where other traditional methods have failed. Finally, it is concluded that the statistical methods and models developed in this thesis will increase the understanding for predictions within and across aquatic systems.
145

Estimativas de (co) varância genética de pesos do nascimento até a maturidade em rebanhos da raça Nelore usando modelos de regressão aleatória e de características múltiplas /

Boligon, Arione Augusti. January 2008 (has links)
Resumo: Foram estimados parâmetros genéticos para pesos do nascimento à idade adulta de animais da raça Nelore por meio de análises uni, bi e multicaracterísticas e modelos de regressão aleatória. Os dados utilizados são de animais nascidos de 1975 e 2002, provenientes de 8 fazendas participantes do Programa de Melhoramento Genético da Raça Nelore (PMGRN). Os pesos foram obtidos do nascimento aos 8 anos de idade. Nas análises uni, bi e multicaracterísticas foram utilizados pesos em idades padrão como nascimento, desmama, ano, sobreano e aos 2, 3 e 5 anos de idade. Também foram realizadas análises utilizando o peso mais próximo aos 4,5 anos de idade como indicativo de peso adulto, considerando uma única medida a partir de 2, 3 e 4 anos de idade ou como registros repetidos de pesos a partir dessas mesmas idades. Nas análises de regressão aleatória, foram utilizados pesos de fêmeas do nascimento aos 8 anos de idade, considerando como variáveis independentes polinômios de Legendre da idade na data da pesagem. A variância residual foi modelada por meio de classes variando de 1 a 5. Foram utilizados 8 modelos de coeficientes de regressão aleatória para os efeitos direto e materno de animal, e de ambiente permanente de animal e materno. O modelo multicaracterística, incluindo registros de pesos ao desmame e à seleção é o mais indicado para a avaliação genética de pesos pós-desmama. Em avaliações genéticas para a característica de peso adulto, o emprego de modelos de repetibilidade, considerando pesos a partir de 3 anos de idade, seria o mais adequado em relação à utilização de medida única...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Weight records of Nelore cattle from birth to mature age were analyzed using univariate, bivariate, multivariate and random regression models. Records of Nelore cattle born from 1975 to 2002, from 8 herds participating in the Nelore Cattle Breeding Program (NCBP) were used. The weights were obtained from birth to 8 years of age. Weights at birth, weaning, yearling, 18 months and 2, 3 and 5 years of age were analyzed using univariate, bivariate and multivariate models. Also, as indicative of the mature weight, the weight closest to 4.5 years of age, was analyzed considering only one record or repeated records obtained from 2, 3 and 4 years of age. For random regression models age of cow varied from birth to 8 years. Direct and maternal genetic and, animal and maternal permanent environmental variances were modeled by random regression on Legendre polynomials of age at recording, with order of fit from 3 to 6 and a total of 8 models. Residual variances were modeled by a step function with 1 or 5 classes. The multivariate model including weight records at weaning and at selection age is the most indicated for genetic evaluation of pos-weaning weights. For genetic evaluation of mature weight to use repeated records obtained from 3 years of age is better than only one record per animal. The random regression models were able to model changes of variances with age adequately, with parameter estimates similar to those obtained by multivariate analyses. The model with direct and maternal genetic effects, animal and maternal permanent environmental effects ajusted by quartic, cubic, sixth and cubic polynomials, respectively, and residual variances modeled by 5 classes, was the most adequate to describe the covariance structure of the data...(Complete abstract, click electronic access below) / Orientadora: Lucia Galvão de Albuquerque / Coorientadora: Maria Eugênia Zerlotti Mercadante / Banca: Henrique Nunes de Oliveira / Banca: Cláudia Cristina Paro de Paz / Mestre
146

Analysis of the potential of ISSQN revenue collection in Maracanaà / AnÃlise do potencial arrecadatÃrio do ISSQN no MunicÃpio de MaracanaÃ

Sheilane Tatiane Mendes Monteiro 27 February 2012 (has links)
nÃo hà / This work aims to raise the fundraising potential of the ISS as a main source of revenue each municipality's MaracanaÃ. The analysis was the main source of information crossing the Department of Finance in relation to the collection of the ISS in the years 2006 to 2010 (base SEFIN) and base register of the IRS and the Board of Trade of the State of CearÃ. Comparing databases, there is, from the outset, a much larger base of taxpayers the IRS and the Board of Trade that the base of SEFIN. Thus, in view of the possibility of an increase in the collection, it was decided to search this potential through a linear regression model, assuming as the dependent variable and independent variables fundraising capital, type of company (provider or receiver service) and business size (large or small), both variables with explanatory power. We conclude that in MaracanaÃ, studies showed that there is great potential for revenue collection in the ISS. / Com este trabalho pretendeu-se levantar o potencial de arrecadaÃÃo do ISSQN como fonte principal da receita prÃpria do municÃpio de MaracanaÃ. A anÃlise teve como fonte principal o cruzamento das informaÃÃes da Secretaria de FinanÃas no que se refere à arrecadaÃÃo do ISSQN nos anos de 2006 a 2010 (base SEFIN) e a base cadastral da Receita Federal e da Junta Comercial do Estado do CearÃ. Comparando as bases de dados, observa-se, jà de inÃcio, uma quantidade muito maior de contribuintes na base da Receita Federal e da Junta Comercial do que na base da SEFIN. Dessa forma, tendo em vista a possibilidade de incremento na arrecadaÃÃo, resolveu-se pesquisar esse potencial por meio de um modelo de regressÃo linear, assumindo como variÃvel dependente a arrecadaÃÃo e como variÃveis independentes o capital social, o tipo de empresa (prestadora ou tomadora de serviÃo) e o porte empresarial (pequeno ou grande porte), ambas como variÃveis com poder de explicaÃÃo. Conclui-se que no municÃpio de MaracanaÃ, os estudos apontaram que existe um grande potencial de arrecadaÃÃo no recolhimento do ISSQN.
147

Análise da dinâmica do potássio e nitrato em colunas de solo não saturado por meio de modelos não lineares e multiresposta / Analysis of the dynamics of potassium and nitrate in soil columns unsaturated through nonlinear model and multi-response

Ana Patricia Bastos Peixoto 02 August 2013 (has links)
Nos últimos anos grande número de modelos computacionais tem sido propostos com o intuito de descrever o movimento de solutos no perfil do solo, apesar disso, o que se observa é que existe grande dificuldade em se modelar esses fenômenos, para que o modelo possa predizer o processo de deslocamento e retenção dos solutos na natureza. Para tanto, o objetivo deste trabalho foi utilizar um modelo estatístico para descrever o transporte dos solutos no perfil do solo. Dessa forma, foi realizado um experimento em laboratório e observado os níveis de potássio e nitrato ao longo do perfil dos solos Latossolo Vermelho Amarelo e Nitossolo Vermelho. Para inferir sobre essas variáveis foram consideradas duas abordagens. Para a primeira abordagem foi utilizado um modelo de regressão não linear para cada uma das variáveis, cujos parâmetros do modelo apresentam uma interpretação prática, na área de solos. Para esse modelo foi realizado um esboço sobre a não linearidade do mesmo para verificar as propriedades assintóticas dos estimadores dos parâmetros. Para o método de estimação foi considerado, o método de mínimos quadrados e o método de bootstrap. Além disso, foi realizada uma análise de diagnóstico para verificar a adequação do modelo, bem como identificar pontos discrepantes. Por outro lado, para outra abordagem, foi utilizado um modelo multiresposta para analisar o comportamento das variáveis nitrato e potássio ao longo do perfil dos solos, conjuntamente. Para esse modelo foi utilizado o método da máxima verossimilhança para encontrar as estimativas dos parâmetros do modelo. Em ambas as situações, observou-se a adequação dos modelos para descrever o comportamento dos solutos nos solos, sendo uma alternativa para os pesquisadores que trabalham com estudo de solos. O modelo logístico com quatro parâmetros se destacou por apresentar melhores propriedades, como medidas de não linearidade e boa qualidade de ajuste. / In the last years, several computational models have been proposed to describe the movement of solutes in the soil profile, but what is observed is that there is great difficulty in model these phenomena, so that model can predict the displacement process and retention of solutes in nature. Thus, the aim of this study was to use a statistical model to describe the transport of solutes in the soil profile. Therefore, an experiment was conducted in the laboratory and observed levels of potassium and nitrate along the depth of soil Oxisol (Haplustox) and Hapludox,. To make inferences about these variables were considered two approaches. For the first approach was utilized a non-linear regression model for each variable and the model parameters have a practical interpretation on soil. For this model we performed a sketch on the nonlinearity of the model to check the asymptotic properties of parameter estimators. To estimate the parameters were considered the least squares method and the bootstrap method. In addition, we performed a diagnostic analysis to verify the adequacy of the model and identify outliers. In the second approach considered was using a multi-response model to analyze the behavior of the variables nitrate and potassium throughout the soil profile together. For this model we used the maximum likelihood method to estimate the model parameters. In both cases, we observed the suitability of the models to describe the behavior of solutes in soils, being an alternative for researchers working on the study of soils. The logistic model with four parameters stood out with better properties, such as non-linearity and good fit.
148

Uma abordagem Bayesiana para análise de sobrevivência de clones de eucaliptos no pólo gesseiro do Araripe-PE

SILVA, Dâmocles Aurélio Nascimento da 24 February 2006 (has links)
Submitted by (ana.araujo@ufrpe.br) on 2016-06-28T13:38:54Z No. of bitstreams: 1 Damocles Aurelio Nascimento da Silva.pdf: 694209 bytes, checksum: 1f6f75597b9348c94d982a8d8a612c8e (MD5) / Made available in DSpace on 2016-06-28T13:38:54Z (GMT). No. of bitstreams: 1 Damocles Aurelio Nascimento da Silva.pdf: 694209 bytes, checksum: 1f6f75597b9348c94d982a8d8a612c8e (MD5) Previous issue date: 2006-02-24 / Aiming at to contribute, as alternative to minimize the resources of impacts,mainly, for the search of combustible material to take care of the energy demand of the Brazilian half-barren region, we use the techniques of analysis of survival for understanding of a forest of eucalyptus to the long one of the time, and with this to ration the use wooden as combustible for ceramics, bakeries and existing calcinatory of plaster in region. The data given proceeding from a transversal study of 1500 cells of eucalyptus, divided in 4 stratus, taking as base the period of 03/2002 to 09/2004. The graph of probability was used initially for, being based on the test of Anderson-Darling, takes the decision of which function of probability would use in such a way in the classic study as in the Bayesian boarding. A time taken to the decision of choice of the probability distribution, we use the method of Kaplan-Meier and the Actuarial method (life table) to determine the estimates of the parameters and the test distribution free log-rank to test if the curves of the function of probability differed between categories from one same one variable. We used this test to the level of significance of 5%. For these analyses, it was used statistical software Minitab 13 version and statistical package SAS.In the Bayesian boarding was used method Carlo the Mount Chain of Markov (MCMC) for estimate of parameters, using as priori the distribution gamma,found in literature as the distribution that more good was adjusted for biological data and as function of density, used it of the Weibull distribution, chosen as of the better adjustment to the data according to test of Anderson-darling. For thisanalysis software Winbugs 1.4 was used. The results how much to the analysis of the parameters they had indicated that the joined estimates had been closed, same using distinct methods of estimation. As much was concluded that the best distribution to analyze the population in question is the Weibull, according to test of Anderson-Darling and as method for estimation of the parameters of the distribution, the classic method,how much the Bayesian method, reveals good estimators, verified for the amplitude of the intervals reliable 95%. In face of the results, we conclude that if it must have one better control of the eucalyptus, in first the six months of the plantation. / Visando contribuir, como alternativa para minimizar os impactos antrópicos de caracter negativo causado, principalmente, pela busca de material combustível para atender a demanda energética da região semi-árida brasileira, utilizamos as técnicas de análise de sobrevivência para compreensão do comportamento de uma floresta de eucaliptos ao longo do tempo, e com isto racionar o uso de madeira como combustível por cerâmicas, padarias, casas de farinha e calcinadoras de gesso existentes na região. Usaremos dados provenientes de um estudo transversal de 1500 células de eucaliptos, dividido em 4 estratos, tomando como base o período de 03/2002 a 09/2004.Utilizou-se inicialmente o gráfico de probabilidade para, baseado no teste de Anderson-Darling, tomarmos a decisão de qual função de probabilidade utilizaríamos tanto no estudo clássico como na abordagem bayesiana. Uma vez tomada a decisão de escolha da distribuição de probabilidade, utilizamos o método de Kaplan-Meier e o método Atuarial (tábua de vida) para estimativa dos parâmetros e o teste não paramétrico log-rank para testar se as curvas da função de probabilidade diferiam entre categorias de uma mesma variável. Utilizamos esse teste ao nível de significância de 0,05. Para essas análises, foi utilizado o software estatístico Minitab versão 13 e o pacote estatístico SAS.Na abordagem bayesiana utilizou-se a o método de Monte Carlo Cadeia de Markov (MCMC) para estimativa dos parâmetros, utilizando como priori a distribuição gamma, encontrada na literatura como a distribuição que melhor adequa-se para dados biológicos e como função de densidade, utilizou-se a da distribuição Weibull, escolhida como a de melhor ajuste as dados segundo o teste de Anderson-Darling. Para essa análise foi utilizado o Winbugs 1.4.Os resultados quanto a análise dos parâmetros indicaram que as estimativas encontradas foram próxima, mesmo utilizando métodos de estimação distintos. Conclui-se que a melhor distribuição para analisar a população em questão é a Weibull, segundo o teste de Anderson-Darling e como método para estimação dos parâmetros da distribuição, tanto o método clássico, quanto o método bayesiano, mostram-se bons estimadores, verificado pela amplitude dos intervalos de confiança a 95%. Em face dos resultados, concluímos que deve-seter um melhor controle dos eucaliptos, nos primeiros 6 meses de plantio.
149

Relação entre atributos do solo e da planta e a resposta espectral da cana-de-açucar / Relationship between soil and plant attributes and the spectral response of the sugarcane plantation

Lourenço, Leonardo Sene de 21 February 2005 (has links)
Orientador: Mara de Andrade Marinho Weill / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-05T13:28:12Z (GMT). No. of bitstreams: 1 Lourenco_LeonardoSenede_M.pdf: 607870 bytes, checksum: fe4db0d68393c2258c9d6605c0faa233 (MD5) Previous issue date: 2005 / Resumo: O desenvolvimento de sensores orbitais de alta resolução espacial e espectral e a perspectiva de maior periodicidade na obtenção de imagens tem incentivado a aplicação crescente de técnicas de sensoriamento remoto no estudo de características espectrais das culturas relacionadas com seu potencial de produção. Os chamados índices de vegetação têm sido utilizados como critérios para estimar a resposta espectral da cultura e, indiretamente, sua produtividade. A resposta espectral é uma medida do vigor vegetativo da cultura, sendo afetada por fatores ambientais, do manejo e da planta. O presente estudo teve por objetivo central estudar a influência de atributos do solo e da planta na variação da resposta espectral da cultura da cana-de-açúcar, medida por meio do índice de vegetação da diferença normalizada (NDVI), aplicando métodos estatísticos uni e multivariados. O estudo foi realizado em um talhão de produção comercial de cana-de-açúcar de cerca de 26 ha, no município de Araras (SP), entre as coordenadas 47º19¿02¿ e 47º19¿26¿ W e 22º21¿53¿ e 22º22¿12¿ S. A lavoura foi implantada em setembro de 1997 com a variedade SP80-1842, precoce, de hábito decumbente e acamamento regular. O delineamento amostral constou de uma grade regular, composta por 67 pontos amostrais georreferenciados e espaçados de 50 m nas direções X e Y, de onde foram extraídas amostras de solo (camadas 0- 30 cm e 30-60 cm) e foliares. As amostras de solo foram extraídas em setembro de 2000 e de 2001, logo após a colheita. As amostras foliares foram extraídas durante a fase de desenvolvimento vegetativo da cultura, no mês de janeiro de 2001 e de 2002. Os anos agrícolas estudados correspondem ao 4º (2000/01) e 5º (2001/02) cortes. Foram avaliados atributos granulométricos e de fertilidade do solo e os teores foliares de macro e micronutrientes (variáveis preditoras). O índice de vegetação NDVI (variável predita) foi calculado a partir de imagens LANDSAT 7, sensor ETM+, obtidas em duas épocas durante a fase de desenvolvimento vegetativo da cultura. Para análise da influência da variação dos atributos edáficos e foliares na variação observada no NDVI foram empregados os métodos estatísticos referidos por análise exploratória, análise de agrupamentos, análise de componentes principais e análise de regressão linear múltipla, adotando-se o método stepwise para seleção de variáveis e ajuste dos modelos. Foram ajustados dois modelos de regressão linear múltipla. O modelo de regressão ajustado aos dados de 2000/01 explicou 30,8% da variação observada da resposta espectral em função da matéria orgânica (M.O., 0-30 cm) e dos teores foliares de fósforo (P, Planta) e de ferro (Fe, Planta). A inclusão desses atributos no modelo pode ser interpretada no caso da matéria orgânica pela similaridade com o NDVI, conforme resultado da análise de agrupamento; no caso do ferro por sua representatividade como integrante do 1º componente principal, e no caso do fósforo por sua baixa correlação com os demais atributos analisados, conforme indicado pela análise exploratória. O modelo de regressão ajustado aos dados de 2001/02 explicou 29,8% da variação observada da resposta espectral em função dos teores de cobre (Cu) e ferro (Fe) na camada 0-30 cm e do teor de enxofre (S-SO4) na camada 30-60 cm. Interpreta-se a inclusão desses atributos no modelo no caso do enxofre por sua representatividade como integrante do 1º componente principal e do ferro como integrante do 3º componente. No caso do cobre, sua inclusão deve estar baseada na média correlação com a resposta espectral (NDVI) e baixa correlação com os demais atributos do modelo, de acordo com os dados da análise exploratória. Os resultados obtidos permitiram comprovar a hipótese do trabalho. Parte da variação observada da resposta espectral na área de estudo pôde ser explicada pela variação de atributos do solo (fator de produção) e da planta. No entanto, entende-se que a capacidade de explicação dos modelos poderia ter sido maior caso tivessem sido incluídas na análise outras variáveis, sobretudo climáticas, bem como, variáveis edáficas que permitissem avaliar o efeito de fatores como compactação e resistência à penetração, tendo em vista se tratar de solos argilosos e muito argilosos / Abstract: The development of multispectral sensors with high spatial and spectral resolutions and the perspective of greater regularity in the attainment of the images have stimulated the increasing application of the remote sensing techniques in the study of spectral response patterns of the crops relating with their potential of production. The spectral response pattern is a measure of the vegetative vigor of a crop, being affected by genotype, management and environmental factors. The main objective of the present research was to study the influence of selected soil and plant attributes in the observed variation of the spectral response pattern of the sugarcane crop, measured by means of the normalized difference vegetation index (NDVI), applying multivariate statistics methods. The study was developed in a commercial area (26 ha) of sugarcane production in Araras (SP), between the coordinates 47º19'02 "and 47º19'26" W and 22º21'53"and 22º22'12" S. The crop was installed in September/1997 with the variety SP80-1842. The experimental delineation was a regular grid, composed by 67 points of sampling, georeferenced, and spaced of 50 m in the X and Y directions, from where had been extracted the plant (leaves) and the soil samples (0-30 cm and 30-60 cm). The soil samples were extracted in September (2000 and 2001), after the harvest. The plants were sampled during the phase of vegetative development of the crop, in January (2001 and 2002). The attributes evaluated were grain sized and fertility attributes (soils) and nutrient contents in leaves (plant). The vegetation index NDVI was calculated from LANDSAT 7, sensor ETM+ images. The statistics methods of analysis have included exploratory analysis, cluster analysis, principal component analysis (PCA), and multiple regression analysis, using the stepwise criterion for selection of the variables and model adjustment. Two linear multiple regression models have been adjusted. The first model (2001/02) could explain 30,8% of the observed variation of NDVI as a function of the soil organic matter (M.O., 0-30 cm) and of the phosphorus (P, Plant) and of the iron (Fe, Plant) contents in leaves. The inclusion of these attributes in the model can be interpreted with basis on the case of the soil organic matter for its similarity with the NDVI, as indicated by cluster analysis. In the case of the iron content its inclusion could be interpreted for its significance as integrant of the first component in PCA, and in the case of the P content with basis on its low correlation with the all others attributes, as indicated for the exploratory analysis. The second regression model (2001/02) could explain 29,8% of the observed variation of NDVI as a function of soil contents of copper (Cu) and iron (Fe) in the first layer (0-30 cm) and the sulphur content (S-SO4) in the second layer (30-60 cm). The inclusion of these attributes in the second model can be interpreted in the case of the S-SO4 content according its significance as integrant of first component in PCA, and the iron content according its significance as integrant of third component in PCA. In the case of copper, its inclusion must be explained with basis in its average correlation with the NDVI and small correlation with the all other attributes of the model, as indicated for the exploratory analysis. The results have permitted to accept the hypothesis of the work. Part of the observed variation of the spectral response pattern in the study area could be explained by the local variation of some soil (production factor) and plant attributes. However, that the capacity of explanation of the two adjusted models could have been better if another variables, in particular the ones related with climate and soil hardness, have been included in the analysis / Mestrado / Planejamento e Desenvolvimento Rural Sustentável / Mestre em Engenharia Agrícola
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Parametrização dimensional, por modelo de regressão, de próteses de mão para crianças, confeccionadas por manufatura aditiva / Dimensional parameterization, by regression model, of hand prostheses for children, made by additive manufacture

Maia, Bruno Alves 24 August 2016 (has links)
Submitted by Erika Demachki (erikademachki@gmail.com) on 2017-02-16T16:21:52Z No. of bitstreams: 2 Dissertação - Bruno Alves Maia - 2016.pdf: 9862769 bytes, checksum: da6934df826a53e405a0f542815fc54d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2017-02-17T16:53:04Z (GMT) No. of bitstreams: 2 Dissertação - Bruno Alves Maia - 2016.pdf: 9862769 bytes, checksum: da6934df826a53e405a0f542815fc54d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-02-17T16:53:04Z (GMT). No. of bitstreams: 2 Dissertação - Bruno Alves Maia - 2016.pdf: 9862769 bytes, checksum: da6934df826a53e405a0f542815fc54d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-08-24 / The use of artificial limbs provides great improvements in the quality of life of people who were born with malformation or have lost their upper limbs. However, the value of conventional prostheses is not accessible to the majority of the population. In order to change this reality, began to emerge projects using additive manufacturing. The use of such technology allows the manufacture of more accessible and customized prostheses. However, the adequacy of project design is still a problem, due to the lack of data on the size of the upper limbs, especially on children and adolescents. Based on this need, this work seeks to find a way to parameterize the hand dimensions, thus helping in the better dimensioning of the prostheses. Thus, this work looks for a variable that presents satisfactory correlation with the dimensions of the upper limb. After finding such a relationship, a table and a parametric model were created that can estimate the length of the hand from the height. / A utilização de membros artificiais proporciona grandes melhorias na qualidade de vida de pessoas que nasceram com malformação ou perderam os membros superiores. No entanto, o valor das próteses convencionais não é acessível à maioria da população. Com o objetivo de modificar essa realidade, começaram a surgir projetos utilizando a manufatura aditiva. O emprego de tal tecnologia, permite a confecção de próteses mais acessíveis e customizadas. Porém, o dimensionamento adequado dos projetos ainda é um problema, devido à falta de dados relativos ao tamanho dos membros superiores, principalmente sobre crianças e adolescentes. Com base nessa necessidade, este trabalho busca encontrar uma forma de parametrizar as dimensões da mão, auxiliando assim no melhor dimensionamento das próteses. Sendo assim, este trabalho procura uma variável que apresenta correlação satisfatória com as dimensões do membro superior. Após encontrar tal relação, foram criados uma tabela e um modelo paramétrico que conseguem estimar o comprimento da mão a partir da estatura.

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