Results 91 to 100 of about 285,691 (282)

Testing Proportionality of Covariance Matrices

The Annals of Mathematical Statistics, 1951
The problem of comparing the proportionality of covariance matrices often arises in genetic experiments. Knowledge of nonproportionality of covariance matrices is useful in selection work and in genetic interpretations. In developing a test of significance for this contrast, the likelihood ratio criterion was used.
openaire   +2 more sources

Sleep Alters the Velocity of Physiological Brain Pulsations in Humans

Advanced Science, EarlyView.
Sleep alters I/CSF oscillatory flow, driven by increased respiratory (29%) and vasomotor pulsation (21%) velocities, while cardiovascular pulsations decreased by (22%). Velocity is quantified using optical flow analysis of MREG data. Spectral power increases alongside these pulsations (spatial correlation, r = 0.35 and r = 0.39, respectively ...
Ahmed Elabasy, Heta Helakari, Tommi Väyrynen, Zalán Rajna, Niko Huotari, Lauri Raitamaa, Ville Isokoski, Matti Järvelä, Mika Kaakinen, Johanna Piispala, Mika Kallio, Vesa Korhonen, Tapio Seppänen, Vesa Kiviniemi   +13 more
wiley   +1 more source

Machine‐Learning Decomposition Identifies a Big Two Structure in Human Personality with Distinct Neurocognitive Profiles

Advanced Science, EarlyView.
Using machine learning on a mega‐scale global dataset (n = 1,336,840) reveals a robust personality trait architecture beyond the Big Five. A Big Two model, broadly capturing social engagement and internal mentation, defines a geometric space that links personality to neurocognitive profiles.
Kaixiang Zhuang, Ji Chen, Jinfeng Han, Wei Cheng, Jiang Qiu, Jianfeng Feng, Simon Eickhoff, Deniz Vatansever   +7 more
wiley   +1 more source

Heuristically Adaptive Diffusion‐Model Evolutionary Strategy

Advanced Science, EarlyView.
Building on the mathematical equivalence between diffusion models and evolutionary algorithms, researchers demonstrate unprecedented control over evolutionary optimization through conditional diffusion. By training diffusion models to associate parameters with specific traits, they can guide evolution toward solutions exhibiting desired behaviors ...
Benedikt Hartl, Yanbo Zhang, Hananel Hazan, Michael Levin   +3 more
wiley   +1 more source

Interpolation and Extrapolation of Toeplitz Matrices via Optimal Mass Transport

, 2018
In this work, we propose a novel method for quantifying distances between Toeplitz structured covariance matrices. By exploiting the spectral representation of Toeplitz matrices, the proposed distance measure is defined based on an optimal mass transport
Elvander, Filip, Jakobsson, Andreas, Karlsson, Johan   +2 more
core   +1 more source

Covariance Characterization by Partial Autocorrelation Matrices

The Annals of Statistics, 1978
It is known that the autocorrelation function of a stationary discrete-time scalar process can be uniquely characterized by the so-called partial autocorrelation function, which is a sequence of numbers less or equal to one in magnitude. We show here that the matrix covariance function of a multivariate stationary process can be characterized by a ...
Morf, M., Vieira, A., Kailath, T.
openaire   +2 more sources

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

Characteristic Polynomials of Sample Covariance Matrices [PDF]

Journal of Theoretical Probability, 2010
We investigate the second-order correlation function of the characteristic polynomial of a sample covariance matrix. Starting from an explicit formula for the generating function, we re-obtain several well-known kernels from random matrix theory.
openaire   +3 more sources

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

Linearizing and Forecasting: A Reservoir Computing Route to Digital Twins of the Brain

Advanced Science, EarlyView.
A new approach uses simple neural networks to create digital twins of brain activity, capturing how different patterns unfold over time. The method generates and recovers key dynamics even from noisy data. When applied to fMRI, it predicts brain signals and reveals distinctive activity patterns across regions and individuals, opening possibilities for ...
Gabriele Di Antonio, Tommaso Gili, Andrea Gabrielli, Maurizio Mattia   +3 more
wiley   +1 more source