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During the past few years, nonextensive statistics has been successfully applied to explain many different kinds of systems. Through these studies some interpretations of the entropic parameter q, which has major role in this statistics, in…

Statistical Mechanics · Physics 2011-07-01 D. O. Soares-Pinto , M. S. Reis , R. S. Sarthour , I. S. Oliveira

Anisotropic light transport is extremely common among scattering materials, yet a comprehensive picture of how macroscopic diffusion is determined by microscopic tensor scattering coefficients is not fully established yet. In this work, we…

Tracer tests in natural porous media sometimes show abnormalities that suggest considering a fractional variant of the Advection Diffusion Equation supplemented by a time derivative of non-integer order. We are describing an inverse method…

Classical Physics · Physics 2017-06-30 Boris Maryshev , Alain Cartalade , Christelle Latrille , Marie-Christine Néel

Tyler's and Maronna's M-estimators, as well as their regularized variants, are popular robust methods to estimate the scatter or covariance matrix of a multivariate distribution. In this work, we study the non-asymptotic behavior of these…

Statistics Theory · Mathematics 2023-06-21 Elad Romanov , Gil Kur , Boaz Nadler

We consider statistical inference in factor analysis for ergodic and non-ergodic diffusion processes from discrete observations. Factor model based on high frequency time series data has been mainly discussed in the field of high…

Statistics Theory · Mathematics 2022-02-04 Shogo Kusano , Masayuki Uchida

A generalized covariant method of analysis applicable to frames for which time is not orthogonal to space, such as spacetime around a star possessing angular momentum or on a rotating disk, is presented. Important aspects of such an…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Robert D. Klauber

We analyze the well-posedness of an anisotropic, nonlocal diffusion equation. Establishing an equivalence between weighted and unweighted anisotropic nonlocal diffusion operators in the vein of unified nonlocal vector calculus, we apply our…

Analysis of PDEs · Mathematics 2021-01-13 Marta D'Elia , Mamikon Gulian

It has been proposed that complex populations, such as those that arise in genomics studies, may exhibit dependencies among observations as well as among variables. This gives rise to the challenging problem of analyzing unreplicated…

Machine Learning · Statistics 2018-06-08 Michael Hornstein , Roger Fan , Kerby Shedden , Shuheng Zhou

Echocardiography plays a fundamental role in the extraction of important clinical parameters (e.g. left ventricular volume and ejection fraction) required to determine the presence and severity of heart-related conditions. When deploying…

Computer Vision and Pattern Recognition · Computer Science 2025-02-19 Thierry Judge , Olivier Bernard , Woo-Jin Cho Kim , Alberto Gomez , Arian Beqiri , Agisilaos Chartsias , Pierre-Marc Jodoin

We consider the inverse problem of reconstructing an effective model for a prototypical diffusion process in strongly heterogeneous media based on coarse measurements. The approach is motivated by quasi-local numerical effective forward…

Numerical Analysis · Mathematics 2020-05-05 Alfonso Caiazzo , Roland Maier , Daniel Peterseim

This paper develops a new statistical inference theory for the precision matrix of high-frequency data in a high-dimensional setting. The focus is not only on point estimation but also on interval estimation and hypothesis testing for…

Statistics Theory · Mathematics 2020-05-20 Yuta Koike

The purpose of this work is to extend the formalism of stochastic calculus to the case of spaces with local anisotropy (modeled as vector bundles with compatible nonlinear and distinguished connections and metric structures and containing…

General Relativity and Quantum Cosmology · Physics 2008-02-03 Sergiu I. Vacaru

Modern developments in microscopy and image processing are revolutionising areas of physics, chemistry, and biology as nanoscale objects can be tracked with unprecedented accuracy. However, the price paid for having a direct visualisation…

Statistical Mechanics · Physics 2013-03-19 Denis Boyer , David S. Dean , Carlos Mejía-Monasterio , Gleb Oshanin

In complex systems, crucial parameters are often subject to unpredictable changes in time. Climate, biological evolution and networks provide numerous examples for such non-stationarities. In many cases, improved statistical models are…

Statistical Finance · Quantitative Finance 2015-12-09 Frederik Meudt , Martin Theissen , Rudi Schäfer , Thomas Guhr

The determination of the covariance matrix and its inverse, the precision matrix, is critical in the statistical analysis of cosmological measurements. The covariance matrix is typically estimated with a limited number of simulations at…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-22 Marnix J. Looijmans , Mike Shengbo Wang , Florian Beutler

Multivariate elliptically-contoured distributions are widely used for modeling correlated and non-Gaussian data. In this work, we study the kurtosis of the elliptical model, which is an important parameter in many statistical analysis.…

Statistics Theory · Mathematics 2024-08-23 Bowen Zhou , Peirong Xu , Cheng Wang

Self-diffusion coefficients, $D^*$, are routinely estimated from molecular dynamics simulations by fitting a linear model to the observed mean-squared displacements (MSDs) of mobile species. MSDs derived from simulation exhibit statistical…

Statistical Mechanics · Physics 2026-01-05 Andrew R. McCluskey , Samuel W. Coles , Benjamin J. Morgan

We introduce a \textit{non-modal} analysis technique that characterizes the diffusion properties of spectral element methods for linear convection-diffusion systems. While strictly speaking only valid for linear problems, the analysis is…

Computational Physics · Physics 2019-01-30 Pablo Fernandez , Rodrigo Moura , Gianmarco Mengaldo , Jaime Peraire

The non-parametric estimation of covariance lies at the heart of functional data analysis, whether for curve or surface-valued data. The case of a two-dimensional domain poses both statistical and computational challenges, which are…

Statistics Theory · Mathematics 2022-01-19 Tomas Masak , Soham Sarkar , Victor M. Panaretos

Diffusion-weighted magnetic resonance imaging (dMRI) is widely used to assess the brain white matter. One of the most common computations in dMRI involves cross-subject tract-specific analysis, whereby dMRI-derived biomarkers are compared…

Image and Video Processing · Electrical Eng. & Systems 2023-07-12 Davood Karimi , Hamza Kebiri , Ali Gholipour