Results 51 to 60 of about 615,565 (289)

An estimate of the inflation factor and analysis sensitivity in the ensemble Kalman filter [PDF]

open access: yesNonlinear Processes in Geophysics, 2017
The ensemble Kalman filter (EnKF) is a widely used ensemble-based assimilation method, which estimates the forecast error covariance matrix using a Monte Carlo approach that involves an ensemble of short-term forecasts.
G. Wu, G. Wu, X. Zheng
doaj   +1 more source

DOA-Estimation Method Based on Improved Spatial-Smoothing Technique

open access: yesMathematics, 2023
To improve the data utilization of the sensor array and direction-of-arrival-(DOA)-estimation performance for coherent signals, a DOA-estimation method with a modified spatial-smoothing technique is proposed. The covariance matrix of the received data of
Yujun Hou   +4 more
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

Normal‐Appearing White Matter Injury Mediates Chronic Deep Venous Hypoxia and Disease Progression in Multiple Sclerosis

open access: yesAnnals of Clinical and Translational Neurology, EarlyView.
ABSTRACT Objective To explore how cerebral hypoxia and Normal‐Appearing White Matter (NAWM) integrity affect MS lesion burden and clinical course. Methods Seventy‐nine MS patients, including 13 clinically isolated syndrome (CIS) patients and 66 relapsing–remitting multiple sclerosis (RRMS) patients, and 44 healthy controls (HCs) were recruited from ...
Xinli Wang   +8 more
wiley   +1 more source

Channel covariance matrix based secret key generation for low‐power terminals in frequency division duplex systems

open access: yesElectronics Letters, 2021
The existing secret key generation (SKG) techniques are not applicable for frequency division duplex (FDD) Internet of Things networks due to the low power constraints and limited computing resources.
Zheng Wan   +3 more
doaj   +1 more source

Moments of minors of Wishart matrices

open access: yes, 2008
For a random matrix following a Wishart distribution, we derive formulas for the expectation and the covariance matrix of compound matrices. The compound matrix of order $m$ is populated by all $m\times m$-minors of the Wishart matrix.
Drton, Mathias   +2 more
core   +2 more sources

An unbiased estimator for the ellipticity from image moments [PDF]

open access: yes, 2017
An unbiased estimator for the ellipticity of an object in a noisy image is given in terms of the image moments. Three assumptions are made: i) the pixel noise is normally distributed, although with arbitrary covariance matrix, ii) the image moments are ...
Tessore, Nicolas
core   +2 more sources

Memory and Resting‐State Connectivity in Acute Transient Global Amnesia: A Case–Control fMRI Study

open access: yesAnnals of Clinical and Translational Neurology, EarlyView.
ABSTRACT Background and Objectives Transient global amnesia (TGA) is a striking model of isolated amnesia. While hippocampal lesions are well described, the network‐level mechanisms and the precise neuropsychological profile remain debated. Our objective was thus to characterize functional and neuropsychological correlates of acute TGA and their ...
Elias El Otmani   +10 more
wiley   +1 more source

Cholesky-based model averaging for covariance matrix estimation

open access: yesStatistical Theory and Related Fields, 2017
Estimation of large covariance matrices is of great importance in multivariate analysis. The modified Cholesky decomposition is a commonly used technique in covariance matrix estimation given a specific order of variables.
Hao Zheng   +3 more
doaj   +1 more source

A Robust Capon Beamforming Approach for Sparse Array Based on Importance Resampling Compressive Covariance Sensing

open access: yesIEEE Access, 2019
Reconstructing the interference-plus-noise covariance matrix instead of searching for the optimal diagonal loading factor for the sample covariance matrix is a good method for calculating the adaptive beamforming coefficients.
Yuguan Hou   +5 more
doaj   +1 more source

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