187 resultados para Modelagem e Simulação
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The mathematical models are critical to determine theoretical prices of options and analyze whether they are overrated or underrated. This information strongly influence in operations carried out by the investor. Therefore, it is necessary that the employee model present high degree of reliability and be consistent with the reality of investment to which it is intended. In this sense, this dissertation aims to apply the steps of mathematical modeling in the Pricing of options for decision making in the investment of a hydroelectric power plant. Was used a Monte Carlo simulation, with the Latin Hypercube Method, to determine the volatility of returns of the project. In order to validate the proposed model, compared to the results found by the Binomial Model, which is one of the models most used in this type of investment. The results reinforce the hypothesis that the mathematical modeling with the Binomial Model is critical to investment decision-making in hydroelectric power
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A simulação de tendências futuras no setor de fertilizantes encaminha o produtor rural a prevenir-se de bruscas variações de preços, possibilitando maior poder de concorrência no cenário internacional. Para tanto, propõe-se a utilização da metodologia ARIMA para se estimar a demanda do consumo de fertilizantes no Brasil. Primeiramente revisitando a literatura especializada, obtendo informações históricas relevantes, além de avaliar as vicissitudes do cenário atual. A segunda parte introduz os conceitos da metodologia ARIMA , e encerrando com a apresentação dos dados e análises estatísticas da previsão 2012 à 2016
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Pós-graduação em Zootecnia - FCAV
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Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA
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Pós-graduação em Matemática em Rede Nacional - IBILCE
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Pós-graduação em Engenharia Mecânica - FEG
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The numeric simulation is an important tool applied in understanding the dynamics of groundwater flow. In a hydrogeological model the processes responsible for groundwater flow are described by numerical formulations that allow the simplification, representation and understanding of the dynamics of the Aquifer System. In this work, a steady state groundwater flow simulation of Urucuia Aquifer System (UAS) part of the Corrente river basin was conducted, using the finite element method through software FEFLOW, to understand the dynamics of groundwater flow and quantify the hydrologic balance. The aquifer system Urucuia lodges in the São Francisco hydrogeological province and corresponds to a set of interconnected aquifers that occur in rocks from Urucuia group in the Urucuia sub-basin described by Campos e Dardenne (1997). The system is a porous media one, in a shape of a thick table mountain, consisting essentially of sandstones. The Corrente river basin is located in UAS in Western State of Bahia and it's one of the main units to maintaining permanent flow (Q95) and average natural flow of the São Francisco river. The simulation performed in this work obtained the following results for the modelled region: horizontal hydraulic conductivity of 3 x 10-4 m/s and vertical one 6 x 10-5 m/s; maximum recharge of 345 mm and minimum of 85 mm/a. It was concluded that: (1) regional groundwater flow has eastbound; with an exception of the extreme northeast portion, where the flow has opposite direction; (2) there are smaller water side dividers with an approximate direction EW, that guide the flow of water to the drainage that cut the aquifer; and (3) the UAS at Corrente river basin can be understood as a free regional aquifer system, isotropic and homogeneous. Regionally, the small lithological variations present in the Urucuia group can be neglected and do not exhibit significant influences on the dynamics of ground water flow
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The water management in any area is highly important to the success of many business and also of life and the understanding of your relationship with the environment brings better control to its demand. I.e. hydrogeological studies are needed under better understanding of the behavior of an aquifer, so that its management is done so as not to deplete or harm it. The objective of this work is the numerical modeling in transient regime of a portion of the Rio Claro aquifer formation in order to get answers about its hydrogeological parameters, its main flow direction and also its most sensitive parameters. A literature review and conceptual characterization of the aquifer, combined with field campaigns and monitoring of local water level (NA), enabled the subsequent construction of the mathematical model by finite elements method, using the FEFLOW 6.1 ® computational algorithm. The study site includes the campus of UNESP and residential and industrial areas of Rio Claro city. Its area of 9.73 km ² was divided into 318040 triangular elements spread over six layers, totaling a volume of 0.25 km³. The local topography and geological contacts were obtained from previous geological and geophysical studies as well as profiles of campus wells and SIAGAS / CPRM system. The seven monitoring wells on campus were set up as observation points for calibration and checking of the simulation results. Sampling and characterization of Rio Claro sandstones shows up a high hydrological and lithological heterogeneity for the aquifer formation. The simulation results indicate values of hydraulic conductivity between 10-6 and 10-4 m / s, getting the Recharge/Rainfall simulation in transient ratio at 13%. Even with the simplifications imposed on the model, it was able to represent the fluctuations of local NA over a year of monitoring. The result was the exit of 3774770 m³ of water and the consequently NA fall. The model is considered representative for the...
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The objective of this study was to simulate the potential stem and sugar yield of sugar cane (Saccharum officinarum L.) in the Northeastern Brazil (Petrolina-PE and Teresina-PI) and analyze 4 varieties in different planting seasons in two environments: irrigated and rainfed cultivars. The model of simulation was DSSAT/CANEGRO (Decision Support System for Agrotechnology Transfer) and the four sugar cane varieties were as follows: RB86 7515, CTC 4, CTC 7 and CTC 20 (all in 1.5 year cycle). Analysis of variance was performed on the results and means were compared using the Tukey test with probability level at 5%. March is the recommended month for planting in Teresina, PI. In Petrolina, PE, rainfed planting is not advisable because of the extended water deficit all year long. In an irrigated environment, no difference was found concerning stem yield as a function of planting season, for all varieties in the study regions. The stem and sugar yields were always higher in irrigated environment as compared with those in rainfed environment in all municipalities and study varieties. The simulation model provided good estimate of stem and sugar yields as compared with experimental data in Teresina, PI.
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A caracterização anatômica, física, mecânica e química da madeira fornece informações importantes para sua melhor utilização. Contudo, para que madeiras se tornem boa opção para o mercado de pisos, adicionalmente é necessária a realização de ensaios que simulem suas reais condições em serviço. Esses ensaios simulam o pisoteio executado pelos sapatos de salto com pequenas áreas de pressão, o arraste e a queda de objetos, a resistência à abrasão da superfície e o atrito oferecido durante o deslocamento de pessoas que caminham sobre ele. Grande dificuldade da seleção de novas madeiras para pisos está na ausência de valores de referência físico-mecânicos. O presente trabalho visou a caracterizar as madeiras de Eucalyptus clöeziana F. Muell, de Eucalyptus microcorys F. Muell e de Corymbia maculata Hook, para as propriedades de densidade básica, retratibilidade, aplicação de carga rolante, de atrito estático e dinâmico, endentação causada por cargas aplicadas em pequenas áreas, impacto da esfera de aço cadente e resistência à abrasão. Foi observado que as madeiras estudadas podem ser utilizadas para a confecção de pisos, de acordo com seus resultados obtidos e por meio de comparações com resultados de literatura.
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Em trabalho realizado em 1998, no município de Taiúva-SP, objetivou-se avaliar o efeito da simulação da deriva de doses crescentes, até atingir a recomendada comercialmente, de clomazone, em duas formulações, e de clomazone em mistura com ametryne, em laranjeira-'Hamlin' com frutos com 2 a 4 cm de diâmetro. O delineamento experimental utilizado foi o de blocos casualizados, com 15 tratamentos, em 3 repetições. As avaliações basearam-se em possíveis alterações morfofisiológicas das plantas, com determinações do teor de clorofila total nas folhas, porcentagem de abortamento de frutos, além de análise tecnológica dos frutos. Concluiu-se que a dose comercial de clomazone isolado e em mistura com ametryne a 50 e 100% da dose resultou na formação de manchas cloróticas e/ou necróticas na casca do fruto e causou mortalidade de ramos que se encontravam em crescimento vegetativo, não acarretando qualquer alteração qualitativa do suco.
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The objective of this work was to evaluate the effect of the variables number of recipients, synchronization protocol, reproductive efficiency indicators and pregnancy cost, in the economic effectiveness of in vivo and in vitro bovine embryo production. A simulation application was elaborated to allow the user to insert the input variable parameters. A basic scenario, from the efficiency traditional rates of in vivo (ET) and in vitro production (IVP) techniques of bovine embryos, was introduced in the software as a criterion to compare the results. This software was able to reproduce both ET and IVP scenarios. The embryo production was simulated through stochastic simulation. The optimal number of recipients using sensitivity analysis was determined. The net present value and cost per pregnancy were used as a decision parameter. The synchronization for fixed-time embryo transfer decreased the recipient idleness and, consequently, the final cost of pregnancy, in comparison to the traditional methodology. Foetal sexing must be associated to IVP of bovine embryos. In addition, the optimal recipient number per donor is variable and depends on data inserted in the system.
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Genetic parameters for weights (17, 942 records), obtained in intervals of 60 days, from the birth to selection (378 days of age), of 2,582 males of the Nellore breed was estimated in univariate analyses by the Maximum Restricted Likelihood method. The models of analysis models included the fixed effects of contemporary groups, month of birth, mother age and age when the weights were collected as covariate. Three models differing in random effects were tested: the model 1 (M1) was adjusted for the direct and maternal addictive genetic effects and maternal permanent environment; in model 2 (M2) the maternal genetic effect was excluded; and the model 3 (M3) was only adjusted for the direct addictive genetic effect. The test of likelihood (LRT) detected significant differences, for all the ages, of M2 and M1 in relation to the simple model (M3), evidencing the importance of the maternal effects. Except for the birth weight (0.40), low values (0.05 to 0.12) of h(2) were found for M1 and M2 until 8 months of age and, after this period, reasonable increase could be observed, reaching 0.28 until 13 months of age. The estimates of the total variance fraction, due to the effect of maternal permanent environment, were high and practically became unaffected between the models 1 and 2. Maternal effects, not necessarily decomposed (in genetic addictive and permanent environment), affected the Nellore males growth. Models that contemplate maternal effects, besides the genetic addictive direct effects, are more realistic to describe the trajectory of the variances in the initial phases of growth of Nelore male calves.
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A cobertura vegetal do solo é decisiva para redução dos efeitos erosivos do impacto direto das gotas de chuva na superfície do solo. Desta forma, objetivou-se com este estudo determinar o índice de cobertura vegetal (CV) e desenvolver modelos para sua estimativa para a cultura da soja, usando os atributos climáticos no período de chuvas intensas no Sul de Minas Gerais. As determinações da CV foram feitas semanalmente, na área experimental do Departamento de Ciência do Solo, Universidade Federal de Lavras (UFLA), no período de novembro de 1999 a maio de 2000, em 28 cultivares de soja com potencial para cultivo nesta região. Para avaliação da cobertura vegetal foi utilizada a metodologia descrita por Stocking (1988). Na modelagem procurou-se relacionar a CV com os valores acumulados dos seguintes atributos climáticos: temperatura média (Tmed), precipitação (PREC) e umidade relativa do ar (UR). Os valores de cobertura vegetal apresentaram uma amplitude de variação de 56 a 83%, sendo BR 162, LO 12 L e M. Soy 108 as cultivares mais eficientes e FT Abyara e Tucano as menos eficientes. O hábito diferencial de crescimento das cultivares ajuda a explicar esse comportamento. O modelo ajustado adequado para estimativa da CV foi: CV = 116589,976 + 0,422 . Tmed + 0,132 . PREC - 0,095 . UR + 0,000024 . Tmed², R² = 0,99 (P < 0,01). A determinação da CV nas diferentes fases de desenvolvimento da cultura é de grande importância, uma vez que seu estabelecimento coincide com o período de maior potencial erosivo das chuvas na região estudada.
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Desenvolveu-se um estudo de simulação estocástica com o objetivo de verificar as consequências do uso combinado de acasalamento dirigido e sêmen sexado em uma população de bovinos de corte sob seleção. Simularam-se seis gerações de seleção para três cenários de acasalamento e uso de sêmen sexado. O primeiro cenário foi caracterizado por acasalamento aleatório e uso exclusivo de sêmen convencional. O segundo cenário caracterizou-se pelo uso de acasalamento associativo positivo nas 40% melhores vacas e acasalamento associativo negativo nas demais, sem uso de sêmen sexado. O terceiro cenário seguiu o mesmo procedimento de acasalamento do segundo, combinando-o com uso de sêmen sexado nas vacas submetidas a acasalamento associativo positivo. O acasalamento associativo positivo teve maior impacto no progresso genético que o uso de sêmen sexado, apesar de ter aumentado a incidência de endogamia na população. O uso de acasalamento associativo negativo foi ineficiente em reduzir a variabilidade dos animais destinados ao abate. O uso combinado de acasalmento associativo positivo e sêmen sexado aumentou a produção de animais geneticamente superiores.