Results 21 to 30 of about 250,897 (267)

Adaptive covariance matrix estimation through block thresholding [PDF]

, 2012
Estimation of large covariance matrices has drawn considerable recent attention, and the theoretical focus so far has mainly been on developing a minimax theory over a fixed parameter space.
Cai, T. Tony, Yuan, Ming
core   +3 more sources

Adaptive Thresholding for Sparse Covariance Matrix Estimation [PDF]

, 2011
In this paper we consider estimation of sparse covariance matrices and propose a thresholding procedure which is adaptive to the variability of individual entries.
Hawkins D. L., Tony Cai, Weidong Liu
core   +4 more sources

Shoreline Delineation from Synthetic Aperture Radar (SAR) Imagery for High and Low Tidal States in Data-Deficient Niger Delta Region

Journal of Marine Science and Engineering, 2023
Satellite image analysis is a potentially powerful tool for monitoring coastal shoreline positions. This study explores the use of multi-temporal, dual-polarised Sentinel-1 GRD synthetic aperture radar (SAR) imagery with a spatial resolution of 10 m for ...
Emmanuel Chigozie Dike, Abiodun Kolawole Oyetunji, Chiemela Victor Amaechi   +2 more
doaj   +1 more source

Large Covariance Estimation by Thresholding Principal Orthogonal Complements [PDF]

, 2013
This paper deals with the estimation of a high-dimensional covariance with a conditional sparsity structure and fast-diverging eigenvalues. By assuming sparse error covariance matrix in an approximate factor model, we allow for the presence of some cross-
Fan, Jianqing, Liao, Yuan, Mincheva, Martina   +2 more
core   +2 more sources

Anomaly Detection in Multichannel Data Using Sparse Representation in RADWT Frames

Mathematics, 2021
We introduce a new methodology for anomaly detection (AD) in multichannel fast oscillating signals based on nonparametric penalized regression. Assuming the signals share similar shapes and characteristics, the estimation procedures are based on the use ...
Daniela De Canditiis, Italia De Feis
doaj   +1 more source

Matrix Recipes for Hard Thresholding Methods

, 2013
In this paper, we present and analyze a new set of low-rank recovery algorithms for linear inverse problems within the class of hard thresholding methods.
Anastasios Kyrillidis, Hard Thresholding Methods, Volkan Cevher   +2 more
core   +2 more sources

IoT-Based Information System for Healthcare Application: Design Methodology Approach

Applied Sciences, 2017
Over the last few decades, life expectancy has increased significantly. However, elderly people who live on their own often need assistance due to mobility difficulties, symptoms of dementia or other health problems.
Damian Dziak, Bartosz Jachimczyk, Wlodek J. Kulesza   +2 more
doaj   +1 more source

Cross-calibration of multiple optical instruments for the measurement of particle size distributions in water

Frontiers in Marine Science
Particle size spectra, describing particle abundance as a function of size, are essential for understanding marine ecosystem structure and biogeochemical processes. The slopes of size spectra provide insights into ecosystem characteristics.
Marika Takeuchi, Zonghua Liu, Zonghua Liu, Will Major, Yéssica Vanessa Contreras-Pacheco, Thangavel Thevar, Jack Rees Williams, Sarah Lou Carolin Giering   +7 more
doaj   +1 more source

Locally Adaptive Tree-Based Thresholding Using the treethresh Package in R

Journal of Statistical Software, 2017
This paper introduces the treethresh package offering accurate estimation, via thresholding, of potentially sparse heterogeneous signals and the denoising of images using wavelets.
Ludger Evers, Tim Heaton
doaj   +1 more source

Order thresholding

, 2010
A new thresholding method, based on L-statistics and called order thresholding, is proposed as a technique for improving the power when testing against high-dimensional alternatives.
Akritas, Michael G., Kim, Min Hee
core   +1 more source