Results 51 to 60 of about 924,331 (302)

Covariance Matrix Reconstruction of GRACE Monthly Solutions Using Common Factors and Individual Formal Errors

open access: yesIEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Accurate error covariance is crucial for postprocessing gravity recovery and climate experiment (GRACE) gravity field solutions in terms of spherical harmonic coefficients (SHCs).
Lin Zhang   +3 more
doaj   +1 more source

Patch-Based Principal Covariance Discriminative Learning for Image Set Classification

open access: yesIEEE Access, 2017
Image set classification has attracted increasing attention with respect to the use of significant amounts of within-set information. The covariance matrix is a natural and effective descriptor for describing image sets. Non-singular covariance matrices,
Hengliang Tan, Ying Gao
doaj   +1 more source

Physical properties of the Schur complement of local covariance matrices [PDF]

open access: yes, 2007
General properties of global covariance matrices representing bipartite Gaussian states can be decomposed into properties of local covariance matrices and their Schur complements. We demonstrate that given a bipartite Gaussian state $\rho_{12}$ described
Eisert J Wolf M M   +7 more
core   +2 more sources

Comparing approximate methods for mock catalogues and covariance matrices II: power spectrum multipoles [PDF]

open access: yesMonthly notices of the Royal Astronomical Society, 2018
We study the accuracy of several approximate methods for gravitational dynamics in terms of halo power spectrum multipoles and their estimated covariance matrix.
Linda Blot   +21 more
semanticscholar   +1 more source

Estimating Covariance Matrices

open access: yesThe Annals of Statistics, 1991
Let \(S_ 1\sim W_ p(\Sigma_ 1,n_ 1)\) and \(S_ 2\sim W_ p(\Sigma_ 2,n_ 2)\) be two independent \(p\times p\) Wishart matrices. It is desired to consider the minimax estimation of \((\Sigma_ 1,\Sigma_ 2)\) under the loss function \[ \sum_{i=1}^ 2\{\hbox {tr}(\Sigma_ i^{-1}\hat\Sigma_ i-\log| \Sigma_ i^{- 1}\hat\Sigma_ i|-p\}, \] extending known results ...
openaire   +2 more sources

A Robust Adaptive Unscented Kalman Filter for Nonlinear Estimation with Uncertain Noise Covariance

open access: yesSensors, 2018
The Unscented Kalman filter (UKF) may suffer from performance degradation and even divergence while mismatch between the noise distribution assumed as a priori by users and the actual ones in a real nonlinear system.
Binqi Zheng   +3 more
doaj   +1 more source

Limiting Spectral Distribution of Large-Dimensional Sample Covariance Matrices Generated by the Periodic Autoregressive Model

open access: yesJournal of Mathematics, 2021
The explicit representation for the limiting spectral moments of sample covariance matrices generated by the periodic autoregressive model (PAR) is established.
Jin Zou, Dong Han
doaj   +1 more source

Estimation for the Linear Model with Uncertain Covariance Matrices

open access: yes, 2014
We derive a maximum a posteriori estimator for the linear observation model, where the signal and noise covariance matrices are both uncertain. The uncertainties are treated probabilistically by modeling the covariance matrices with prior inverse-Wishart
Bengtsson, Mats   +4 more
core   +1 more source

Two sample tests for high-dimensional covariance matrices [PDF]

open access: yes, 2012
We propose two tests for the equality of covariance matrices between two high-dimensional populations. One test is on the whole variance--covariance matrices, and the other is on off-diagonal sub-matrices, which define the covariance between two ...
Chen, Song Xi, Li, Jun
core   +3 more sources

Performance of internal Covariance Estimators for Cosmic Shear Correlation Functions [PDF]

open access: yes, 2015
Data re-sampling methods such as the delete-one jackknife are a common tool for estimating the covariance of large scale structure probes. In this paper we investigate the concepts of internal covariance estimation in the context of cosmic shear two ...
Eifler, T. F.   +3 more
core   +2 more sources

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