Maximum Likelihood Estimator
Mostrando 13-24 de 37 artigos, teses e dissertações.
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13. Métodos de ajuste da função Weibull e seu desempenho na prognose do crescimento e produção de Eucalyptus dunnii
The main objective of this research was to develop a simulator system of growth and yield for unthinned plantations of Eucalyptus dunnii using different adjustment methods for the Weibull probability density function to describe the forest structure at various ages. The data used in this research came from measurements of 239 plots in E. dunnii stands in the
Publicado em: 2010
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14. EXTRACTING COMMON FACTORS AMONG EXCHANGE RATE REAL/DOLLAR, EMERGENT MARKET BOND INDEX+BRAZIL AND IBOVESPA, VIA FILTRO DE KALMAN / EXTRAÇÃO DE FATOR COMUM ENTRE AS VOLATILIDADES DOS RETORNOS DA TAXA DE CÂMBIO REAL/DÓLAR, RISCO-PAÍS E IBOVESPA VIA FILTRO DE KALMAN
Historically, financial variables¿ volatilities are drastically affected during economical crisis periods. In particular, this statement is valid for the exchange rate between brazilian and north american currencies, the São Paulo Stock Exchange Index (Ibovespa) and the Emerging Market Bond Index + Brazil, usually interpreted as a measure of brazilian sove
Publicado em: 2010
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15. Família Weibull de razão de chances na presença de covariáveis
A distribuição Weibull é uma escolha inicial freqüente para modelagem de dados com taxas de risco monótonas. Entretanto, esta distribuição não fornece um ajuste paramétrico razoável quando as funções de risco assumem um formato unimodal ou em forma de banheira. Neste contexto, Cooray (2006) propôs uma generalização da família Weibull consider
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 18/03/2009
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16. Estimação de canais MIMO variantes no tempo usando filtros de Kalman / Time-varying MIMO channel estimation using Kalman filters
In this work we use Kalman filters to estimate time-varying wireless channels in multiple-input, multiple-output (MIMO) systems. First, we propose an optimal estimator (in the minimum mean squared error sense) to track flat channels in orthogonal space-time block coded systems. Due to the orthogonality inherent to these codes, the Kalman filter equations can
Publicado em: 2009
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17. Teste de hipóteses sobre o espectro de freqüência, aplicado na manutenção preditiva de motores de indução
This project had begun with the aim of technical improvement and a predictive maintenance tool development for electrical machines diagnosis. Based on nonintrusive approach Motor Current Signature Analysis - MCSA for three-phase induction motor broken bars detection, it was developed a spectral analysis method able to increase accuracy and reliability, compa
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 21/08/2008
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18. Contribuições da teoria da estimação para modulações digitais que utilizam sinais caóticos. / Contributions of the estimation theory to digital modulations that use chaotic signals.
In this work, we investigate the use of estimation techniques to digital modulation systems that use chaotic signals. Initially, basic aspects of nonlinear systems and digital modulation theory are reviewed followed by currently proposed techniques of chaotic digital modulation with coherent, noncoherent and differential correlation receivers: CSK (Chaos Shi
Publicado em: 2006
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19. Avaliação da condição de " tão bom quanto novo":: uma aplicação envolvendo a manutenção de motores convencionais das aeronaves Universal T-5"
After a usual preventive maintenance routine it is usually assumed that a system returns to the condition of As Good As New" (AGAN). This work uses some statistical tools to propose a methodology able to test if a system returns to the Condition of AGAN and, in the cases in which the supposition cannot be validated, to determine a coefficient reliable to mea
Publicado em: 2006
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20. Multiple comparison for binomial parameters using bootstrap / ComparaÃÃes mÃltiplas para parÃmetros binomiais utilizando bootstrap
The multiple comparisons methods and the analysis of variance are not reliable alternatives for comparing two or more binomial proportions, when the experiments have only Bernoulli trails. Although, this comparison can be made using the intensive computational techniques named infinite bootstrap. This work aimed to evaluate the performance of two binomial pr
Publicado em: 2006
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21. Modelling Complex Longitudinal Survey Data
Modelling methods for longitudinal complex survey data are investigated in this thesis. An empirical investigation using longitudinal survey data is conducted. Variance effects of clustering are identified and results indicate that clustering impacts may be stronger for longitudinal studies than for cross-sectional studies. Earlier empirical evidence that th
Publicado em: 2005
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22. MAXIMUM LIKELIHOOD ESTIMATION OF THE DIRECTION-OF-ARRIVAL OF PSK MODULATED CARRIERS / ESTIMAÇÃO DE MÁXIMA VEROSSIMILHANÇA DA DIREÇÃO DE CHEGADA DE PORTADORAS PSK
In mobile communication systems, phase shift keying (PSK) modulation is widely used in digital transmission schemes. Previous works have considered several maximum likelihood (ML) methods for the direction-of-arrival (DOA) estimation of generic signals reaching a phased-array of sensors. This thesis proposes a new ML DOA estimator designed to be used in PSK
Publicado em: 2004
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23. CorreÃÃo de viÃs do estimador de mÃxima verossimilhanÃa para a famÃlia exponencial biparamÃtrica
Maximum likelihood estimators are typically biased. There are several different ways to correct this problem. The chief goal of this dissertation is to present some of them, which focus on removing the second order bias of maximum likelihood estimators in the biparametric exponential family. This may be done by analitical or numerical procedures. We will pre
Publicado em: 2004
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24. EstimaÃÃo pontual e intervalar em um modelo de regressÃo Beta
In this thesis we consider the beta regression model recently proposed by Ferrari &CribariNeto (2003), which is tailored to situations where the response is restricted to the standard unit interval and has a regression structure involving regressors and unknown parameters. We derive the second order biases of the maximum likelihood estimators, and use them t
Publicado em: 2004