Matrix Estimation
Mostrando 1-12 de 94 artigos, teses e dissertações.
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1. Sparse Estimation of the Precision Matrix and Plug-In Principle in Linear Discriminant Analysis for Hyperspectral Image Classification
ABSTRACT In this paper, a new method for supervised classification of hyperspectral images is proposed for the case in which the size of the training sample is small. It consists of replacing in the Mahalanobis distance the maximum likelihood estimator of the precision matrix by a sparse estimator. The method is compared with two other existing versions of L
Trends in Computational and Applied Mathematics. Publicado em: 2022
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2. Mathematical Analysis and Improvement of the Maximum Spatial Eigenfilter for Direction of Arrival Estimation
Abstract Maximum spatial eigenfiltering improves the accuracy of maximum likelihood direction-of-arrival estimators for closely-spaced signal sources but may interchangeably attenuate widely-spaced signal sources, producing a severe performance degradation. Although this behavior has been observed experimentally, it still lacks a mathematical explanation. In
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-03
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3. MULTILEVEL NONLINEAR MIXED-EFFECTS MODEL AND MACHINE LEARNING FOR PREDICTING THE VOLUME OF Eucalyptus SPP. TREES
ABSTRACT Volumetric equations is one of the main tools for quantifying forest stand production, and is the basis for sustainable management of forest plantations. This study aimed to assess the quality of the volumetric estimation of Eucalyptus spp. trees using a mixed-effects model, artificial neural network (ANN) and support-vector machine (SVM). The datab
CERNE. Publicado em: 2020-03
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4. Considering the impact of observation error correlation in ensemble square-root Kalman filter
Abstract Data assimilation has been developed into an effective technology that can utilize a large number of multi-source unconventional data. It cannot only provide the initial field for the ocean numerical prediction model, but also construct the ocean reanalysis datasets and provide the design basis for the ocean observation plan. In data assimilation, t
Braz. j. oceanogr.. Publicado em: 02/12/2019
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5. Elaboração e validação de uma medida para avaliar o conhecimento de médicos de atenção primária do Brasil sobre recomendação nutricional para controle da hipertensão
Resumo Introdução Médicos da Atenção Primária à Saúde têm papel primordial no aconselhamento nutricional para reduzir a morbidade e a mortalidade relacionadas à hipertensão. A literatura é escassa em instrumentos validados para o Brasil que avaliam o conhecimento com base em evidências desses profissionais. Objetivo Elaborar uma medida para av
Cad. saúde colet.. Publicado em: 25/11/2019
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6. REDUCTION OF SAMPLE SIZE IN THE ANALYSIS OF SPATIAL VARIABILITY OF NONSTATIONARY SOIL CHEMICAL ATTRIBUTES
ABSTRACT In the study of spatial variability of soil attributes, it is essential to define a sampling plan with adequate sample size. This study aimed to evaluate, through simulated data, the influence of parameters of the geostatistical model and sampling configuration on the optimization process, and resize and reduce the sample size of a sampling configur
Eng. Agríc.. Publicado em: 09/09/2019
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7. SITE INDEX FOR PROSOPIS ALBA PLANTATIONS IN THE SEMI-ARID CHACO THROUGH MIXED MODELS
ABSTRACT The classification of sites through curves of Site Index allows to predict the yield of the planted forests at a certain age of the stand and to plan cultural treatments. The goal of this research was to compare linear and non-linear models of fixed effects vs. mixed non-linear models to estimate the site index in plantations of Prosopis alba var Gr
CERNE. Publicado em: 09/09/2019
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8. Satellite Inertia Parameters Estimation Based on Extended Kalman Filter
ABSTRACT: The moment of inertia parameters play a critical role in assuring the spacecraft mission throughout its lifetime. However, determination of the moment of inertia is a key challenge in operating satellites. During satellite mission, those parameters can change in orbit for many reasons such as sloshing, fuel consumption, etc. Therefore, the inertia
J. Aerosp. Technol. Manag.. Publicado em: 28/03/2019
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9. Recurrent Algorithm for TDOA Localization in Sensor Networks
ABSTRACT: Using the mathematical apparatus of the extended Kalman Filter, the recurrent algorithm of the passive location in sensor networks - based on the Time Difference of Arrival method in case of correlated errors of measurements - is developed. The initial estimates of Radio Frequency Sources coordinates and the correlation matrix of the vector estimat
J. Aerosp. Technol. Manag.. Publicado em: 02/10/2017
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10. Method Development and Total Uncertainty Estimation for Boron, Sulfur and Phosphorus Determination in Mineral Fertilizer Using ICP OES
This study deals with B, S, and P determination in mineral fertilizer and S in commercial sulfur-formulation using inductively coupled plasma optical emission spectrometry. According to multivariate optimization using a Doehlert matrix, the analytes extraction in fertlizer can be conducted in open flask and heating on hot plate or in closed flask in microwav
J. Braz. Chem. Soc.. Publicado em: 2016-11
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11. State estimation of chemical engineering systems tending to multiple solutions
A well-evaluated state covariance matrix avoids error propagation due to divergence issues and, thereby, it is crucial for a successful state estimator design. In this paper we investigate the performance of the state covariance matrices used in three unconstrained Extended Kalman Filter (EKF) formulations and one constrained EKF formulation (CEKF). As bench
Braz. J. Chem. Eng.. Publicado em: 2014-09
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12. A maximum margin-based kernel width estimator and its application to the response to neoadjuvant chemotherapy
INTRODUCTION: Function induction problems are frequently represented by affinity measures between the elements of the inductive sample set, and kernel matrices are a well-known example of affinity measures. METHODS: The objective of the present work is to obtain information about the relations between data from a calculated kernel matrix by initially assumin
Rev. Bras. Eng. Bioméd.. Publicado em: 2014-03