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The increase in the observed volume in cosmological surveys imposes various challenges on simulation preparations. Firstly, the volume of the simulations required increases proportionally to the observations. However, large-volume…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-01 Daniel Forero-Sánchez , Chia-Hsun Chuang , Sergio Rodríguez-Torres , Gustavo Yepes , Stefan Gottlöber , Cheng Zhao

Szapudi et al (2001) introduced the method of estimating angular power spectrum of the CMB sky via heuristically weighted correlation functions. Part of the new technique is that all (co)variances are evaluated by massive Monte Carlo…

Astrophysics · Physics 2007-05-23 I. Szapudi , S. Prunet , S. Colombi

Weak lensing experiments are a powerful probe of cosmology through their measurement of the mass distribution of the universe. A challenge for this technique is to control systematic errors that occur when measuring the shapes of distant…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Alexandre Refregier , Tomasz Kacprzak , Adam Amara , Sarah Bridle , Barnaby Rowe

We have investigated the statistical clustering properties of galaxies by calculating the 2-point galaxy correlation function from the Durham/UKST Galaxy Redshift Survey. This survey is magnitude limited to bj = 17, contains 2500 galaxies…

Astrophysics · Physics 2009-10-30 A. Ratcliffe , T. Shanks , Q. A. Parker , R. Fong , .

A novel stochastic technique combining a dilute source grid of $\mathbb{Z}_3$ noise with iterative momentum-smearing is used to study the proton correlation function at rest and in boosted frames on two lattice volumes. The technique makes…

High Energy Physics - Lattice · Physics 2018-12-05 J. -J. Wu , W. Kamleh , D. ~B. Leinweber , R. D. Young , J. M. Zanotti

We propose new methods for multivariate linear regression when the regression coefficient matrix is sparse and the error covariance matrix is dense. We assume that the error covariance matrix has equicorrelation across the response…

Methodology · Statistics 2025-08-13 Daeyoung Ham , Bradley S. Price , Adam J. Rothman

Covariance matrices are essential cosmological probes of fundamental physics, providing information on numerous fundamental physical parameters and varying with any change in the underlying cosmology. However, this cosmology dependence,…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-21 Theodore Steele , Robert Smith , Roisin O'Connor

The covariance matrix $\boldsymbol{\Sigma}$ of non-linear clustering statistics that are measured in current and upcoming surveys is of fundamental interest for comparing cosmological theory and data and a crucial ingredient for the…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-13 Nicolas Chartier , Benjamin D. Wandelt

We propose a new estimator for the spot covariance matrix of a multi-dimensional continuous semi-martingale log asset price process which is subject to noise and non-synchronous observations. The estimator is constructed based on a local…

Statistics Theory · Mathematics 2017-07-11 Markus Bibinger , Nikolaus Hautsch , Peter Malec , Markus Reiß

Smoothing of noisy sample covariances is an important component in functional data analysis. We propose a novel covariance smoothing method based on penalized splines and associated software. The proposed method is a bivariate spline…

Methodology · Statistics 2017-04-07 Luo Xiao , Cai Li , William Checkley , Ciprian M. Crainiceanu

The evaluation of abstractive summarization models typically uses test data that is identically distributed as training data. In real-world practice, documents to be summarized may contain input noise caused by text extraction artifacts or…

Computation and Language · Computer Science 2023-12-05 Kundan Krishna , Yao Zhao , Jie Ren , Balaji Lakshminarayanan , Jiaming Luo , Mohammad Saleh , Peter J. Liu

Recent studies inspired by results from random matrix theory [1,2,3] found that covariance matrices determined from empirical financial time series appear to contain such a high amount of noise that their structure can essentially be…

Statistical Mechanics · Physics 2009-11-07 Szilard Pafka , Imre Kondor

Two-point correlation functions (2PCF) are widely used to characterize how points cluster in space. In this work, we study the problem of measuring the 2PCF over a large set of points, restricted to a subset satisfying a property of…

Computer Vision and Pattern Recognition · Computer Science 2026-04-08 Max Hamilton , Daniel Sheldon , Subhransu Maji

If properly calibrated, the shapes of galaxy clusters can be used to investigate many physical processes: from feedback and quenching of star formation, to the nature of dark matter. Theorists frequently measure shapes using moments of…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-11 David Harvey , Andrew Robertson , Sut-Ieng Tam , Mathilde Jauzac , Richard Massey , Jason Rhodes , Ian G. McCarthy

We compare the measurements of the bispectrum and the estimate of its covariance obtained from a set of different methods for the efficient generation of approximate dark matter halo catalogs to the same quantities obtained from full N-body…

This paper deals with model order selection in context of correlated noise. More precisely, one considers sources embedded in an additive Complex Elliptically Symmetric (CES) noise, with unknown parameters. The main difficultly for…

Methodology · Statistics 2017-10-19 Eugénie Terreaux , Jean-Philippe Ovarlez , Frédéric Pascal

(abridged) The clustering properties of galaxies belonging to different luminosity ranges or having different morphological types are different. These characteristics or `marks' permit to understand the galaxy catalogs that carry all this…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-14 Vicent J. Martinez , Pablo Arnalte-Mur , Dietrich Stoyan

We propose a novel Metropolis-Hastings algorithm to sample uniformly from the space of correlation matrices. Existing methods in the literature are based on elaborated representations of a correlation matrix, or on complex parametrizations…

Computation · Statistics 2019-10-18 Irene Córdoba , Gherardo Varando , Concha Bielza , Pedro Larrañaga

Lowering the noise level of short pulse lasers has been a long-standing effort for decades. Modeling the noise performance plays a crucial role in isolating the noise sources and reducing them. Modeling to date has either used analytical or…

Applied Physics · Physics 2018-10-17 Shaokang Wang , Thomas F. Carruthers , Curtis R. Menyuk