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The Gaussian process (GP) is a powerful tool for nonparametric modeling, but its sensitivity to outliers limits its applicability to data distributions with heavy-tails. Studentt processes offer a robust alternative for heavy tail modeling,…

Machine Learning · Computer Science 2026-03-11 Jian Xu , Delu Zeng , John Paisley

This paper describes a new Bayesian interpretation of a class of skew--Student $t$ distributions. We consider a hierarchical normal model with unknown covariance matrix and show that by imposing different restrictions on the parameter…

Methodology · Statistics 2018-05-25 Abdolnasser Sadeghkhani

We study the correlations of the shear signal between triplets of sources in the Canada-France-Hawaii Lensing Survey (CFHTLenS) to probe cosmological parameters via the matter bispectrum. In contrast to previous studies, we adopted a…

We consider the shape of the posterior distribution to be used when fitting cosmological models to power spectra measured from galaxy surveys. At very large scales, Gaussian posterior distributions in the power do not approximate the…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-25 Benedict Bahr-Kalus , Will J. Percival , Lado Samushia

Radio interferometric gain calibration can be biased by incomplete sky models and radio frequency interference, resulting in calibration artefacts that can restrict the dynamic range of the resulting images. It has been suggested that…

Instrumentation and Methods for Astrophysics · Physics 2019-10-21 Ulrich Armel Mbou Sob , Hertzog Landman Bester , Oleg Smirnov , Jonathan Kenyon , Trienko Grobler

Naive estimates of the statistics of large scale structure and weak lensing power spectrum measurements that include only Gaussian errors exaggerate their scientific impact. Non-linear evolution and finite volume effects are both…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-24 Emmanuel Schaan , Masahiro Takada , David N. Spergel

This paper considers the robust and efficient implementation of Gaussian process regression with a Student-t observation model. The challenge with the Student-t model is the analytically intractable inference which is why several…

Machine Learning · Statistics 2012-06-28 Pasi Jylänki , Jarno Vanhatalo , Aki Vehtari

The theory of Bayesian learning incorporates the use of Student-t Processes to model heavy-tailed distributions and datasets with outliers. However, despite Student-t Processes having a similar computational complexity as Gaussian…

Machine Learning · Computer Science 2025-08-12 Jian Xu , Delu Zeng

The Heckman selection model is widely used in econometric analysis and other social sciences to address sample selection bias in data modeling. A common assumption in Heckman selection models is that the error terms follow an independent…

Methodology · Statistics 2026-02-09 Heeju Lim , Victor E. Lachos , Victor H. Lachos

In a traditional Gaussian graphical model, data homogeneity is routinely assumed with no extra variables affecting the conditional independence. In modern genomic datasets, there is an abundance of auxiliary information, which often gets…

Methodology · Statistics 2023-08-16 Yabo Niu , Yang Ni , Debdeep Pati , Bani K. Mallick

We present general, analytic methods for Cosmological likelihood analysis and solve the "many-parameters" problem in Cosmology. Maxima are found by Newton's Method, while marginalization over nuisance parameters, and parameter errors and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 A. N. Taylor , T. D. Kitching

We propose a novel generalisation to the Student-t Probabilistic Principal Component methodology which: (1) accounts for an asymmetric distribution of the observation data; (2) is a framework for grouped and generalised…

Methodology · Statistics 2020-09-25 Dorota Toczydlowska , Gareth W. Peters , Pavel V. Shevchenko

A composite likelihood is an inference function derived by multiplying a set of likelihood components. This approach provides a flexible framework for drawing inference when the likelihood function of a statistical model is computationally…

Methodology · Statistics 2024-12-10 Giuseppe Alfonzetti , Ruggero Bellio , Yunxiao Chen , Irini Moustaki

Making inferences about physical properties of the Universe requires knowledge of the data likelihood. A Gaussian distribution is commonly assumed for the uncertainties with a covariance matrix estimated from a set of simulations. The noise…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-09 Jed Homer , Oliver Friedrich , Daniel Gruen

Standard present day large-scale structure (LSS) analyses make a major assumption in their Bayesian parameter inference --- that the likelihood has a Gaussian form. For summary statistics currently used in LSS, this assumption, even if the…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-06 ChangHoon Hahn , Florian Beutler , Manodeep Sinha , Andreas Berlind , Shirley Ho , David W. Hogg

We present a method to transform multivariate unimodal non-Gaussian posterior probability densities into approximately Gaussian ones via non-linear mappings, such as Box--Cox transformations and generalisations thereof. This permits an…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-14 Robert L. Schuhmann , Benjamin Joachimi , Hiranya V. Peiris

Weak gravitational lensing surveys are rapidly becoming important tools to probe directly the mass density fluctuations in the universe and its background dynamics. Earlier studies have shown that it is possible to model the statistics of…

Astrophysics · Physics 2009-11-07 Patrick Valageas , Andrew J. Barber , Dipak Munshi

We study parameter estimation in linear Gaussian covariance models, which are $p$-dimensional Gaussian models with linear constraints on the covariance matrix. Maximum likelihood estimation for this class of models leads to a non-convex…

Statistics Theory · Mathematics 2016-04-19 Piotr Zwiernik , Caroline Uhler , Donald Richards

When fitting cosmological models to data, a Bayesian framework is commonly used, requiring assumptions on the form of the likelihood and model prior. In light of current tensions between different data, it is interesting to investigate the…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-31 Jordan Krywonos , Simone Paradiso , Alex Krolewski , Shahab Joudaki , Will Percival

In Hamiltonian Monte Carlo sampling, the shape of the potential and the choice of the momentum distribution jointly give rise to the Hamiltonian dynamics of the sampler. An efficient sampler propagates quickly in all regions of the…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-28 Javier Silva Lafaurie , Lorne Whiteway , Elena Sellentin , Kutay Nazli , Andrew H. Jaffe , Alan F. Heavens , Arthur Loureiro