Results 71 to 80 of about 444,093 (258)

Unified Pressure and Field Response Across Distinct Charge‐Order Regimes in Ti‐Doped CsV3Sb5

open access: yesAdvanced Functional Materials, EarlyView.
We microscopically investigate the interplay between charge order and superconductivity in a kagome superconductor across regimes of long‐ and short‐range charge order. Hydrostatic‐pressure and magnetic‐field μSR$\mu{\rm SR}$ measurements reveal remarkably similar superconducting and normal‐state time‐reversal‐symmetry‐breaking responses in both ...
P. Kral   +12 more
wiley   +1 more source

The affine equivariant sign covariance matrix: asymptotic behavior and efficiencies. [PDF]

open access: yes
We consider the affine equivariant sign covariance matrix (SCM) introduced by Visuri et al. (J. Statist. Plann. Inference 91 (2000) 557). The population SCM is shown to be proportional to the inverse of the regular covariance matrix. The eigenvectors and
Croux, Christophe, Ollila, E, Oja, H
core  

Beyond Presumptions: Toward Mechanistic Clarity in Metal‐Free Carbon Catalysts for Electrochemical H2O2 Production via Data Science

open access: yesAdvanced Materials, EarlyView.
Metal‐free carbon catalysts enable the sustainable synthesis of hydrogen peroxide via two‐electron oxygen reduction; however, active site complexity continues to hinder reliable interpretation. This review critiques correlation‐based approaches and highlights the importance of orthogonal experimental designs, standardized catalyst passports ...
Dayu Zhu   +3 more
wiley   +1 more source

Estimating High Dimensional Covariance Matrices and its Applications [PDF]

open access: yes
Estimating covariance matrices is an important part of portfolio selection, risk management, and asset pricing. This paper reviews the recent development in estimating high dimensional covariance matrices, where the number of variables can be greater ...
Jushan Bai, Shuzhong Shi
core  

Automatic positive semidefinate HAC covariance matrix and GMM estimation [PDF]

open access: yes, 2005
This paper proposes a new class of heteroskedastic and autocorrelation consistent (HAC) covariance matrix estimators. The standard HAC estimation method reweights estimators of the autocovariances.
Smith, Richard J.
core   +1 more source

Large‐Scale Determination of Frontier Orbital Energies of Disordered Small‐Molecule Organic Semiconductors Using Exciplex Emission Spectra

open access: yesAdvanced Materials, EarlyView.
ABSTRACT Accurately knowing the frontier orbital energies of the structurally disordered small‐molecule organic semiconductors that are used in optoelectronic devices such as organic light‐emitting diodes is required to rationally improve their performance. Here, we show that these energies can be deduced with a large accuracy from the peak energies of
Christian B. McDonald   +7 more
wiley   +1 more source

Using routine hydrographic sections for estimating the parameters needed for Optimal Statistical Interpolation. Application to the northern Alboran Sea

open access: yesScientia Marina, 2005
Optimal Statistical Interpolation is widely applied in the analysis of oceanographic data. This technique requires knowing some statistics of the analysed fields such as the covariance function and the noise to signal ratio.
Manuel Vargas-Yáñez   +3 more
doaj   +1 more source

Flame Detection Method In Video Using Covariance Descriptors [PDF]

open access: yes, 2011
Video fire detection system which uses a spatio-temporal covariance matrix of video data is proposed. This system divides the video into spatio-temporal blocks and computes covariance features extracted from these blocks to detect fire.
Osman Gunay   +7 more
core   +1 more source

Descriptors to Dynamics: A Materials and Device Perspective on in‐Materio Physical Reservoir Computing for Neuromorphic Edge Intelligence

open access: yesAdvanced Materials, EarlyView.
Intrinsic material dynamics are harnessed as computational resources for neuromorphic in‐materio physical reservoir computing. Defects, ionic motion, interfaces, percolation, geometry, and biasing shape transient states that provide fading memory, nonlinearity, and high‐dimensional projection for simple readout. A descriptor‐to‐dynamics framework links
Kshitij RB Singh   +5 more
wiley   +1 more source

Covariance matrix estimation methods for constrained portfolio optimization in a South African setting [PDF]

open access: yes, 2010
One of the major topics of concern in Modern Portfolio Theory is portfolio optimization which is centred on the mean-variance framework. In order for this framework to be implemented, esti- mated parameters (covariance matrix for the constrained portfo ...
Madume, Jaison Pezisai
core   +1 more source

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