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This work is focused on constructing space-time covariance functions through a hierarchical mixture approach that can serve as building blocks for capturing complex dependency structures. This hierarchical mixture approach provides a…

统计方法学 · 统计学 2025-11-14 Pulong Ma

Rayleigh-L\'evy flights are simplified cosmological tools which capture certain essential statistical properties of the cosmic density field, including hierarchical structures in higher-order correlations, making them a valuable reference…

宇宙学与河外天体物理 · 物理学 2026-01-14 Reginald Christian Bernardo , Stephen Appleby , Francis Bernardeau , Christophe Pichon

This paper is the first in a set that analyses the covariance matrices of clustering statistics obtained from several approximate methods for gravitational structure formation. We focus here on the covariance matrices of anisotropic…

This paper presents a study of power series distributions (PSD) with prescribed covariance characteristics. Such distributions constitute a fundamental class in probability theory and mathematical statistics, as they generalize a wide range…

统计理论 · 数学 2025-12-23 Oleksandr Volkov , Yurii Volkov , Nataliia Voinalovych

We analyse the covariance of the one-dimensional mass power spectrum along lines of sight. The covariance reveals the correlation between different modes of fluctuations in the cosmic density field and gives the sample variance error for…

天体物理学 · 物理学 2009-11-10 Hu Zhan , Daniel Eisenstein

Covariance functions are the core of spatial statistics, stochastic processes, machine learning as well as many other theoretical and applied disciplines. The properties of the covariance function at small and large distances determine the…

统计理论 · 数学 2023-01-16 Alfredo Alegría , Fabián Ramírez , Emilio Porcu

Mathematical models based on probability density functions (PDF) have been extensively used in hydrology and subsurface flow problems, to describe the uncertainty in porous media properties (e.g., permeability modelled as random field).…

流体动力学 · 物理学 2020-06-01 Matteo Icardi , Marco Dentz

We develop a diagrammatic technique to represent the multi-point cumulative probability density function (CPDF) of mass fluctuations in terms of the statistical properties of individual collapsed objects and relate this to other statistical…

天体物理学 · 物理学 2009-10-31 Dipak Munshi , Peter Coles , Adrian L. Melott

The problem of detecting changes in covariance for a single pair of features has been studied in some detail, but may be limited in importance or general applicability. In contrast, testing equality of covariance matrices of a {\it set} of…

统计方法学 · 统计学 2017-12-12 Yi-Hui Zhou

We calculate the one-point probability distribution function (PDF) for cosmic density in non-linear regime of the gravitational evolution. Under the local approximation that the evolution of cosmic fluid fields can be characterized by the…

天体物理学 · 物理学 2009-11-10 Yasuhiro Ohta , Issha Kayo , Atsushi Taruya

We investigate the bias and error in estimates of the cosmological parameter covariance matrix, due to sampling or modelling the data covariance matrix, for likelihood width and peak scatter estimators. We show that these estimators do not…

宇宙学与河外天体物理 · 物理学 2015-06-18 Andy Taylor , Benjamin Joachimi

This paper presents a general formalism that allows the derivation of the cumulant generating function and one-point Probability Distribution Function (PDF) of the aperture mass ($\hat{M}_{ap}$), a common observable for cosmic shear…

宇宙学与河外天体物理 · 物理学 2018-01-31 Paulo Reimberg , Francis Bernardeau

Very often, in the course of uncertainty quantification tasks or data analysis, one has to deal with high-dimensional random variables (RVs). A high-dimensional RV can be described by its probability density (pdf) and/or by the…

Distributional approximations of (bi--) linear functions of sample variance-covariance matrices play a critical role to analyze vector time series, as they are needed for various purposes, especially to draw inference on the dependence…

概率论 · 数学 2018-03-20 Ansgar Steland , Rainer von Sachs

Turbulence is essential for understanding the structure and dynamics of molecular clouds and star-forming regions. There is a need for adequate tools to describe and characterize the properties of turbulent flows. One-point probability…

天体物理学 · 物理学 2008-11-26 Ralf S. Klessen

Counts-in-cells (CIC) measurements contain a wealth of cosmological information yet are seldom used to constrain theories. Although we can predict the shape of the distribution for a given cosmology, to fit a model to the observed CIC…

宇宙学与河外天体物理 · 物理学 2020-12-02 Andrew Repp , István Szapudi

Our article considers a Gaussian variational approximation of the posterior density in a high-dimensional state space model. The variational parameters to be optimized are the mean vector and the covariance matrix of the approximation. The…

统计方法学 · 统计学 2020-02-20 Matias Quiroz , David J. Nott , Robert Kohn

For Poisson-Delaunay triangulations in $d$-dimensional Euclidean space $\mathbb{R}^{d}$, a structured and computationally efficient form of the probability density function (PDF) of the volume of a typical cell is analytically derived in…

信息论 · 计算机科学 2018-05-11 Minghua Xia , Sonia Aïssa

Using a suite of self-similar cosmological simulations, we measure the probability distribution functions (PDFs) of real-space density, redshift-space density, and their geometric mean. We find that the real-space density PDF is…

宇宙学与河外天体物理 · 物理学 2022-04-27 Huanqing Chen , Nickolay Y. Gnedin , Philip Mansfield

Pairwise likelihood is a useful approximation to the full likelihood function for covariance estimation in high-dimensional context. It simplifies high-dimensional dependencies by combining marginal bivariate likelihood objects, thus making…

统计方法学 · 统计学 2024-07-25 Alessandro Casa , Davide Ferrari , Zhendong Huang