Results 91 to 100 of about 147,262 (309)

Modeling Heterogeneity of the Level-1 Error Covariance Matrix in Multilevel Models for Single-Case Data

Methodology, 2020
Previous research applying multilevel models to single-case data has made a critical assumption that the level-1 error covariance matrix is constant across all participants.
Eunkyeng Baek, John J. M. Ferron
doaj   +1 more source

Consensus Formation and Change are Enhanced by Neutrality

Advanced Science, EarlyView.
Neutral agents are shown to enhance both the formation and overturning of consensus in collective decision‐making. A general mathematical model and experiments with locusts and humans reveal that neutrality enables robust consensus via simple interactions and accelerates consensus change by reducing effective population size.
Andrei Sontag, Janina A. Hoffmann, Tim Rogers, Christian A. Yates   +3 more
wiley   +1 more source

Honey, I shrunk the sample covariance matrix [PDF]

The central message of this paper is that nobody should be using the sample covariance matrix for the purpose of portfolio optimization. It contains estimation error of the kind most likely to perturb a mean-variance optimizer.
Michael Wolf, Olivier Ledoit
core  

In Situ X‐Ray Tomography and Acoustic Emission Monitoring of Damage Evolution in C/C‐SiC Composites Fabricated by Liquid Silicon Infiltration

Advanced Science, EarlyView.
This study investigates how the internal structure of fiber‐reinforced ceramic composites affects their resistance to damage. By combining 3D X‐ray imaging with acoustic emission monitoring during mechanical testing, it reveals how silicon distribution influences crack formation.
Yang Chen, Renato S. M. Almeida, Stefan Flauder, Guillaume Couégnat, Kamen Tushtev, Jürgen Horvath, Peter Wriggers, Kurosch Rezwan   +7 more
wiley   +1 more source

Evaluating Machine Learning Weather Models for Data Assimilation: Fundamental Limitations in Tangent Linear and Adjoint Properties

Geophysical Research Letters
Machine learning (ML) weather models like GraphCast and NeuralGCM show forecasting promise but face fundamental limitations for data assimilation (DA) integration.
Xiaoxu Tian, Daniel Holdaway, Daryl Kleist   +2 more
doaj   +1 more source

Practical aspects of providing pixel-level spectral Rrs error covariance in satellite ocean color products

Frontiers in Remote Sensing
We previously established a derivative-based approach to generate a pixel-level spectral error covariance matrix in satellite-retrieved remote sensing reflectance, ∑Rrs.
Minwei Zhang, Minwei Zhang, Amir Ibrahim, Bryan A. Franz, Andrew M. Sayer, Andrew M. Sayer, P. Jeremy Werdell, Lachlan I. McKinna, Lachlan I. McKinna   +8 more
doaj   +1 more source

Estimation for the Multivariate Errors-in-Variables Model with Estimated Error Covariance Matrix

The Annals of Statistics, 1984
The authors consider the estimation problem of multivariate errors-in- variables models. Let \(r\times 1\) row vectors \(y_ i\) and \(k\times 1\) row vectors \(x_ i\) satisfy \(y_ i=\beta_ 0+x_ i\beta\), \(i=1,2,...,n\), where \(\beta_ 0\) and \(\beta\) are 1\(\times r\) and \(k\times r\) matrices of parameters, respectively.
Amemiya, Yasuo, Fuller, Wayne A.
openaire   +3 more sources

Solid Harmonic Wavelet Bispectrum for Image Analysis

Advanced Science, EarlyView.
The Solid Harmonic Wavelet Bispectrum (SHWB), a rotation‐ and translation‐invariant descriptor that captures higher‐order (phase) correlations in signals, is introduced. Combining wavelet scattering, bispectral analysis, and group theory, SHWB achieves interpretable, data‐efficient representations and demonstrates competitive performance across texture,
Alex Brown, Mathilda Avirett‐Mackenzie, Carolin Villforth, Georgios Exarchakis   +3 more
wiley   +1 more source

Optimal Sensor and Relay Nodes Power Scheduling for Remote State Estimation with Energy Constraint

Sensors, 2020
We study the sensor and relay nodes’ power scheduling problem for the remote state estimation in a Wireless Sensor Network (WSN) with relay nodes over a finite period of time given limited communication energy.
Yufei Han, Mengqi Cui, Shaojun Liu
doaj   +1 more source

Microscale Mapping of Fiber Strain and Damage in Composite Wrinkled Laminates Using Computed Tomography Assisted Wide‐Angle X‐Ray Scattering

Advanced Science, EarlyView.
This study combines full‐field tomography with diffraction mapping to quantify radial (ε002$\varepsilon _{002}$) and axial (ε100$\varepsilon _{100}$) lattice strain in wrinkled carbon‐fiber specimens for the first time. Radial microstrain gradients (−14.5 µεMPa$\varepsilon \mathrm{MPa}$−1) are found to signal damage‐prone zones ahead of failure, which ...
Hoang Minh Luong, James Trevarthen, Igor Dolbnya, Wadwan Singhapong, Nicholas Pilato, Richard Butler, Jiraphant Srisuriyachot, Alexander J. G. Lunt   +7 more
wiley   +1 more source