Least Squares Problem
Mostrando 1-12 de 48 artigos, teses e dissertações.
-
1. Determination of Ethanol in Gel Hand Sanitizers Using Mid and Near Infrared Spectroscopy
Alcohol-based gel hand sanitizers became very popular during the COVID-19 (coronavirus disease 2019) pandemic. In Brazil, several irregular factories emerged requiring an efficient control by the police and regulatory agencies to guarantee product quality. This problem required a method to determine ethanol content, which led to the development of two method
J. Braz. Chem. Soc.. Publicado em: 2020-09
-
2. Theoretical and Experimental Heat Transfer in Solid Propellant Rocket Engine
ABSTRACT: Accurate determination of heat flux is an important task not only in the designing aspect, but also in the performance analysis of rocket engines. In this purpose, this work deals with the heat flux determination in a combustion chamber through the inverse method. In this approach, the transient heat flux is determined from the experimental tempera
J. Aerosp. Technol. Manag.. Publicado em: 26/08/2019
-
3. Simultaneous Determination of Different Phenolic Compounds Using Electrochemical Biosensor and Multivariate Calibration
Phenolic compounds are important environmental contaminants due to their high toxicity and persistence in the environment. The use of enzyme-based electrochemical biosensors is a simple, sensitive and low-cost alternative for the determination of these pollutants in contaminated waters. However, in most cases, it is impossible to detect specific compounds in
J. Braz. Chem. Soc.. Publicado em: 2018-03
-
4. MCR-ALS APLICADO NO MONITORAMENTO QUANTITATIVO DO PROCESSO DE ELETRODEGRADAÇÃO DA ATRAZINA USANDO ESPECTROS UV: RESULTADOS COMPARATIVOS COM HPLC-DAD COMO UM MÉTODO DE REFERÊNCIA
Electrodegradation of atrazine in water was performed using homemade (PA and PB) and purchased (PC) boron-doped diamond anodes. The degradation was monitored off-line by analyzing total organic carbon and high performance liquid chromatography with diode array detector (HPLC-DAD) and at-line by UV spectroscopy. The spectra were recorded every 2 min. The rank
Quím. Nova. Publicado em: 2016-02
-
5. Use of an Automatic System in the Preparation of Gas Mixtures for Multivariate Calibration: A Case Study Involving NIR Analysis of Natural Gas
This paper investigates the use of an automatic system for preparation of gas mixtures in a multivariate calibration problem involving near-infrared (NIR) spectrometric analysis of natural gas. The automatic system is used to prepare calibration mixtures according to a Brereton experimental design, in order to exploit a suitable range of gas concentrations a
J. Braz. Chem. Soc.. Publicado em: 2015-10
-
6. 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
-
7. Controle ótimo por modos deslizantes via função penalidade / Optimal sliding mode control approach penalty function
Este trabalho aborda o problema de controle ótimo por modos deslizantes via função penalidade para sistemas de tempo discreto. Para resolver este problema será desenvolvido uma estrutura matricial alternativa baseada no problema de mínimos quadrados ponderados e funções penalidade. A partir desta nova formulação é possível obter a lei de controle
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 01/07/2011
-
8. Estudo numérico da aplicação do método dos elementos finitos de Galerkin e dos mínimos quadrados na solução da equação da convecção-difusão-reação tridimensional / Numerical study of the application of Galerkin and least squares finite element methods in the solution of the tridimentional convection-diffusion-reaction equation
This paper the application of the Finite Element Method in variants Galerkin and Least Squares with auxiliary equations for the numerical solution of partial differential equation that models the convection-diffusion-reaction defined over a three-dimensional domain in steady state. In the spatial discretization were used hexahedrons elements with eight (line
Publicado em: 2011
-
9. Seismic data inversion by cross-hole tomography using geometrically uniform spatial coverage
One of the inversion schemes most employed in seismic tomography processing is least squares and derived algorithms, using as input data the vector of first arrivals. A division of the whole space between sources and receivers is performed, constructing a pixel model with its elements of the same size. Spatial coverage is defined, then, as the sum of travele
Revista Brasileira de Geofísica. Publicado em: 2010-03
-
10. Estudo teórico experimental da dinâmica de temperatura no interior de uma cavidade cilíndrica. / EXPERIMENTAL THEORETICAL STUDY OF DYNAMIC TEMPERATURE AT A CYLINDRICAL
Two methods for solving a direct heat diffusion problem inside a cylindrical enclosure are proposed, each one is applied with a linear and plus a non-linear solution. Besides, a experimental apparatus was developed for theoretical models validation purpose. Furthermore, as an application of the proposed system the inverse analysis (inverse problem) is used t
Publicado em: 2010
-
11. Diagnostic and reduction of the influence of multicollinearity in the estimation of genetic additive and non-additive effects in multibreed population of cattle (Bos taurus x Bos indicus) / Diagnóstico e redução da influência da multicolinearidade na estimação de efeitos genéticos aditivos e não-aditivos em uma população de bovinos compostos (Bos taurus x Bos indicus)
The genetic additive and heterozygosity effects are important in the genetic evaluation of multibreed populations. When there is strong linear relation between the explanatory variables, the regression coefficients have large standard errors and are sensitive to changes in the data set and to the addition or removal of explanatory variables in the model. The
Publicado em: 2009
-
12. Recursive robust regulator for discrete-time state-space systems / Regulador robusto recursivo para sistemas lineares de tempo discreto no espaço de estado
This dissertation deals with robust recursive regulators for discrete-time systems subject to parametric uncertainties. A new quadratic functional based on the combination of penalty functions and game theory is proposed to solve this class of problems. An important issue of this approach is that the recursiveness can be performed without the need of adjusti
Publicado em: 2009