Nonlinear Least Squares
Mostrando 1-12 de 84 artigos, teses e dissertações.
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1. Vibrational Spectroscopy and Chemometrics in Forensic Chemistry: Critical Review, Current Trends and Challenges
The present manuscript makes an extensive review of the scientific approaches developed in the last decade involving infrared and Raman spectroscopy combined with chemometrics for solving several issues in the investigation of the most relevant forensic traces, such as questioned documents and currency, explosives, gunshot residues, illicit drugs and body fl
J. Braz. Chem. Soc.. Publicado em: 24/10/2019
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2. Comparison and Combination of Techniques for Determining the Parameters of a Magnetic Hysteresis Model
Abstract The Jiles-Atherton scalar hysteresis model presents five parameters used to represent the material tested and used to calculate the magnetic losses. This article presents a comparative analysis of the performance of two methods of identifying these parameters. In the first method, the equations of Jiles-Atherton were assembled into a single non-line
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 12/09/2019
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3. Critical analyses when modeling tree biomass to ensure additivity of its components
ABSTRACT It is presented the theme additivity of biomass of tree components. To evaluate and discuss this context, experimental information collected in forests of Acacia mearnsii De Wild. was used. Equations for components (stem and crown) and total biomass were fitted by means of two procedures: 1) generalized nonlinear least squares and 2) weighted-nonlin
An. Acad. Bras. Ciênc.. Publicado em: 17/05/2018
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4. Bayesian Analysis for the Comparison of Nonlinear Regression Model Parameters: an Application to the Growth of Japanese Quail
ABSTRACT This paper discusses the Bayesian approach as an alternative to the classical analysis of nonlinear models for growth curve data in Japanese quail. A Bayesian nonlinear modeling method is introduced and compared with the classical nonlinear least squares (NLS) method using three non-linear models that are widely used in modeling the growth data of p
Rev. Bras. Cienc. Avic.. Publicado em: 2016-09
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5. PREDICTIVE CONTROL OF A BATCH POLYMERIZATION SYSTEM USING A FEEDFORWARD NEURAL NETWORK WITH ONLINE ADAPTATION BY GENETIC ALGORITHM
Abstract This study used a predictive controller based on an empirical nonlinear model comprising a three-layer feedforward neural network for temperature control of the suspension polymerization process. In addition to the offline training technique, an algorithm was also analyzed for online adaptation of its parameters. For the offline training, the networ
Braz. J. Chem. Eng.. Publicado em: 2016-03
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6. PRECONDITIONING ISSUES IN THE NUMERICAL SOLUTION OF NONLINEAR EQUATIONS AND NONLINEAR LEAST SQUARES
Second order methods for optimization call for the solution of sequences of linear systems. In this survey we will discuss several issues related to the preconditioning of such sequences. Covered topics include both techniques for building updates of factorized preconditioners and quasi-Newton approaches. Sequences of unsymmetric linear systems arising in Ne
Pesqui. Oper.. Publicado em: 2014-12
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7. Estimação e previsão da estrutura a termo das taxas de juros usando técnicas de inteligência computacional / Term structure of interest rate modeling and forecasting using computational intelligence techniques
This work proposes the term structure of interest rates modeling and forecasting using computational intelligence techniques, based on data from the US and Brazilian fixed income markets. The yield curve modeling includes the use of some evolutionary computation methods like Genetic Algorithms, Differential Evolution and Evolution Strategies in comparison wi
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 25/06/2012
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8. Uma nova abordagem para resolução de problemas de fluxo de carga com variáveis discretas / A new approach for solving load flow problems with discrete variables
Este trabalho apresenta uma nova abordagem para a modelagem e resolução de problemas de fluxo de carga em sistemas elétricos de potência. O modelo proposto é formado simultaneamente pelo conjunto de equações não lineares que representam as restrições de carga do problema e por restrições de complementaridade associadas com as restrições de oper
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/05/2012
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9. Drying kinetics, structural characteristics and vitamin C retention of dedo-de-moça pepper (Capsicum baccatum) during convective and freeze drying
The main objective of this study was to evaluate the effect of the drying process on the vitamin C levels and physical properties of dedo-de-moça pepper. The drying kinetics and the structural properties were determined as a function of moisture content. Convective drying was compared with freeze-drying in terms of product quality, structural properties, re
Braz. J. Chem. Eng.. Publicado em: 2012-12
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10. IDENTIFICAÇÃO DE UM SISTEMA DE LODO ATIVADO DE PEQUENA ESCALA DESENVOLVIDO EM LABORATÓRIO / IDENTIFICATION OF A ACTIVATED SLUDGE SYSTEM ON SCALE SMALL DEVELOPED IN THE LABORATORY
In activated sludge systems, the dissolved oxygen is used by microorganisms to decompose organic matter and treatment of wastewater. In these systems the dynamics of dissolved oxygen has been seen as the main source of information to obtain online information about the treatment process. Thus, the development of an appropriate model for the dynamics of disso
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/07/2011
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11. Global convergence of a regularized factorized quasi-Newton method for nonlinear least squares problems
In this paper, we propose a regularized factorized quasi-Newton method with a new Armijo-type line search and prove its global convergence for nonlinear least squares problems. This convergence result is extended to the regularized BFGS and DFP methods for solving strictly convex minimization problems. Some numerical results are presented to show efficiency
Computational & Applied Mathematics. Publicado em: 2010-06
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12. Modelos de regressão PLS com erros heteroscedásticos
Two problems related to Partial Least Squares method are considered in this work. Heteroscedastic errors and an asymmetrical error distribution. In the _rst part of this work a methodology is developed which allows, based in PLS methods, to estimate the model parameters in the presence of non-constant error variance. This technique is compared with the usual
Publicado em: 2010