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Leveraging prior knowledge on intraclass variance due to transformations is a powerful method to improve the sample complexity of deep neural networks. This makes them applicable to practically important use-cases where training data is…

Machine Learning · Computer Science 2022-02-09 Matthias Rath , Alexandru Paul Condurache

The paper proposes a new covariance estimator for large covariance matrices when the variables have a natural ordering. Using the Cholesky decomposition of the inverse, we impose a banded structure on the Cholesky factor, and select the…

Applications · Statistics 2008-12-18 Elizaveta Levina , Adam Rothman , Ji Zhu

In unconstrained maximum a posteriori (MAP) and maximum likelihood estimation, the inverse of minus the merit-function Hessian matrix is an approximation of the estimate covariance matrix. In the Bayesian context of MAP estimation, it is…

Methodology · Statistics 2020-03-17 Dimas Abreu Archanjo Dutra

We present initial results on the use of Mixture Models for density estimation in large astronomical databases. We provide herein both the theoretical and experimental background for using a mixture model of Gaussians based on the…

Astrophysics · Physics 2007-05-23 R. C. Nichol , A. J. Connolly , A. W. Moore , J. Schneider , C. Genovese , L. Wasserman

The requirement to generate robust robotic platforms is a critical enabling step to allow such platforms to permeate safety-critical applications (i.e., the localization of autonomous platforms in urban environments). One of the primary…

Signal Processing · Electrical Eng. & Systems 2019-08-14 Ryan M. Watson , Jason N. Gross , Clark N. Taylor , Robert C. Leishman

We propose a general framework for nonasymptotic covariance matrix estimation making use of concentration inequality-based confidence sets. We specify this framework for the estimation of large sparse covariance matrices through…

Methodology · Statistics 2020-12-17 Adam B Kashlak , Linglong Kong

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…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Andy Taylor , Benjamin Joachimi

Covariance matrix estimation is a fundamental statistical task in many applications, but the sample covariance matrix is sub-optimal when the sample size is comparable to or less than the number of features. Such high-dimensional settings…

Methodology · Statistics 2022-06-06 Huiqin Xin , Sihai Dave Zhao

When analyzing galaxy clustering in multi-band imaging surveys, there is a trade-off between selecting the largest galaxy samples (to minimize the shot noise) and selecting samples with the best photometric redshift (photo-z) precision,…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-07 Dimitrios Tanoglidis , Chihway Chang , Joshua Frieman

Measurement-critical ultrasound tasks often depend on a small anatomical region, making global reconstruction metrics an unreliable proxy for clinical fidelity. We propose an ROI-aware representation learning framework and instantiate it…

Computer Vision and Pattern Recognition · Computer Science 2026-04-28 Ines Abbes , Mahmood Alzubaidi , Mowafa Househ , Khalid Alyafei , Marco Agus , Samir Brahim Belhaouari

Relying on recent advances in statistical estimation of covariance distances based on random matrix theory, this article proposes an improved covariance and precision matrix estimation for a wide family of metrics. The method is shown to…

Machine Learning · Statistics 2021-02-03 Malik Tiomoko , Florent Bouchard , Guillaume Ginholac , Romain Couillet

Covariance matrices are among the most difficult pieces of end-to-end cosmological analyses. In principle, for two-point functions, each component involves a four-point function, and the resulting covariance often has hundreds of thousands…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-20 Tassia Ferreira , Tianqing Zhang , Nianyi Chen , Scott Dodelson

Third-order weak lensing statistics are a promising tool for cosmological analyses since they extract cosmological information in the non-Gaussianity of the cosmic large-scale structure. However, such analyses require precise and accurate…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-26 Laila Linke , Sven Heydenreich , Pierre A. Burger , Peter Schneider

We introduce a new method for estimating the covariance matrix for the galaxy correlation function in surveys of large-scale structure. Our method combines simple theoretical results with a realistic characterization of the survey to…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-31 Ross O'Connell , Daniel Eisenstein , Mariana Vargas , Shirley Ho , Nikhil Padmanabhan

We consider the closely related problems of sampling from a distribution known up to a normalizing constant, and estimating said normalizing constant. We show how variational autoencoders (VAEs) can be applied to this task. In their…

Machine Learning · Computer Science 2022-09-22 George T. Cantwell

Covariance estimation for matrix-valued data has received an increasing interest in applications. Unlike previous works that rely heavily on matrix normal distribution assumption and the requirement of fixed matrix size, we propose a class…

Methodology · Statistics 2022-04-20 Yichi Zhang , Weining Shen , Dehan Kong

We derive an efficient method to perform clustering of nodes in Gaussian graphical models directly from sample data. Nodes are clustered based on the similarity of their network neighborhoods, with edge weights defined by partial…

Machine Learning · Computer Science 2019-10-08 Keith Dillon

We present correction terms that allow delete-one Jackknife and Bootstrap methods to be used to recover unbiased estimates of the data covariance matrix of the two-point correlation function $\xi\left(\mathbf{r}\right)$. We demonstrate the…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-14 Faizan G. Mohammad , Will J. Percival

Repeated measurements are common in many fields, where random variables are observed repeatedly across different subjects. Such data have an underlying hierarchical structure, and it is of interest to learn covariance/correlation at…

Methodology · Statistics 2023-06-13 Sunpeng Duan , Guo Yu , Juntao Duan , Yuedong Wang

Constraints on the validity of the hierarchical gravitational instability theory and the evolution of biasing are presented based upon measurements of higher order clustering statistics in the Deeprange Survey, a catalog of $\sim710,000$…

Astrophysics · Physics 2009-10-31 István Szapudi , Marc Postman , Tod R. Lauer , William Oegerle