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This work proposes a general framework for capturing noise-driven transitions in spatially extended non-equilibrium systems and explains the emergence of coherent patterns beyond the instability onset. The framework relies on stochastic…

Dynamical Systems · Mathematics 2024-12-16 Mickaël D. Chekroun , Honghu Liu , James C. McWilliams

Anisotropy in granular materials arises from both the internal fabric and the directionality of the stress state, yet separating these effects experimentally remains challenging. This study develops a first-order linearisation of the…

Soft Condensed Matter · Physics 2026-04-09 Mehdi Pouragha , Gertraud Medicus , Selvarajah Premnath , Siva Sivathayalan

An unbiased estimator for the ellipticity of an object in a noisy image is given in terms of the image moments. Three assumptions are made: i) the pixel noise is normally distributed, although with arbitrary covariance matrix, ii) the image…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-09 Nicolas Tessore

Many trials are designed to collect outcomes at or around pre-specified times after randomization. If there is variability in the times when participants are actually assessed, this can pose a challenge to learning the effect of treatment,…

We address the problem of simultaneously estimating arc travel times in a network \emph{and} parameters of route choice models for strategic and tactical network planning purposes. Hitherto, these interdependent tasks have been approached…

Methodology · Statistics 2025-11-13 Sobhan Mohammadpour , Emma Frejinger

Homogeneity is a crucial, but poorly tested, assumption in cosmology. We introduce a new approach which allows us to place limits on the presence of localized structures within essentially our entire observable volume, using cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-15 James. P. Zibin , Adam Moss

Strict stationarity is a common assumption used in the time series literature in order to derive asymptotic distributional results for second-order statistics, like sample autocovariances and sample autocorrelations. Focusing on weak…

Statistics Theory · Mathematics 2023-02-28 Yunyi Zhang , Efstathios Paparoditis , Dimitris N. Politis

We present a new method for calculating linear cosmic microwave background (CMB) anisotropy spectra based on integration over sources along the photon past light cone. In this approach the temperature anisotropy is written as a time…

Astrophysics · Physics 2008-11-26 Uros Seljak , Matias Zaldarriaga

This paper analyzes the use of variable speed limits to optimize travel time reliability for commuters. The investigation focuses on a traffic corridor with a bottleneck subject to the capacity drop phenomenon. The optimization criterion is…

Optimization and Control · Mathematics 2025-09-16 Alexander Hammerl , Ravi Seshadri , Thomas Kjær Rasmussen , Otto Anker Nielsen

Collecting real-world mobility data is challenging. It is often fraught with privacy concerns, logistical difficulties, and inherent biases. Moreover, accurately annotating anomalies in large-scale data is nearly impossible, as it demands…

Implicit sampling is a weighted sampling method that is used in data assimilation, where one sequentially updates estimates of the state of a stochastic model based on a stream of noisy or incomplete data. Here we describe how to use…

Numerical Analysis · Mathematics 2016-01-20 Matthias Morzfeld , Xuemin Tu , Jon Wilkening , Alexandre J. Chorin

A nonparametric procedure to estimate the conditional probability that a nonstationary geostatistical process exceeds a certain threshold value is proposed. The method consists of a bootstrap algorithm that combines conditional simulation…

The statistical problem of parameter estimation in partially observed hypoelliptic diffusion processes is naturally occurring in many applications. However, due to the noise structure, where the noise components of the different coordinates…

Methodology · Statistics 2018-11-13 Susanne Ditlevsen , Adeline Samson

Transfer entropy is capable of capturing nonlinear source-destination relations between multi-variate time series. It is a measure of association between source data that are transformed into destination data via a set of linear…

Information Theory · Computer Science 2019-05-28 David Sigtermans

Existing gradient-based optimization methods update parameters locally, in a direction that minimizes the loss function. We study a different approach, symmetry teleportation, that allows parameters to travel a large distance on the loss…

Machine Learning · Computer Science 2023-01-06 Bo Zhao , Nima Dehmamy , Robin Walters , Rose Yu

The simple entropic method to statistical reconstructing of heterogeneous three-dimensional media from a single two-dimensional image is briefly reported. We apply the entropic descriptor quantifying spatial inhomogeneity that depends on…

Statistical Mechanics · Physics 2015-11-18 D. Frączek , W. Olchawa , R. Piasecki , R. Wiśniowski

The majority of present efforts to constrain cosmological parameters with cosmic microwave background (CMB) anisotropy data employ approximate likelihood functions, the time consuming nature of a complete analysis being a major obstacle. We…

Astrophysics · Physics 2007-05-23 M. Douspis , J. G. Bartlett , A. Blanchard , M. Le Dour

We present precise anisotropic interpolation error estimates for smooth functions using a new geometric parameter and derive inverse inequalities on anisotropic meshes. In our theory, the interpolation error is bounded in terms of the…

Numerical Analysis · Mathematics 2022-08-03 Hiroki Ishizaka , Kenta Kobayashi , Takuya Tsuchiya

Considering 3D heterogeneous anisotropic media, in Part III of this study we obtain the finite-element solution for the stationary ray path between two fixed endpoints using the finite element approach. It involves computation of the global…

Geophysics · Physics 2020-03-24 Igor Ravve , Zvi Koren

Weakly collisional space plasmas are rarely in local thermal equilibrium and often exhibit non-Maxwellian electron and ion velocity distributions that lead to the growth of microinstabilities, that is, enhanced electric and magnetic fields…