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We propose a group sparse optimization model for inpainting of a square-integrable isotropic random field on the unit sphere, where the field is represented by spherical harmonics with random complex coefficients. In the proposed…

Optimization and Control · Mathematics 2022-05-10 Chao Li , Xiaojun Chen

The use of a finite mixture of normal distributions in model-based clustering allows to capture non-Gaussian data clusters. However, identifying the clusters from the normal components is challenging and in general either achieved by…

Methodology · Statistics 2016-06-21 Gertraud Malsiner-Walli , Sylvia Frühwirth-Schnatter , Bettina Grün

Estimating physical parameters from data is a crucial application of machine learning (ML) in the physical sciences. However, systematic uncertainties, such as detector miscalibration, induce data distribution distortions that can erode…

Data Analysis, Statistics and Probability · Physics 2025-05-14 Ibrahim Elsharkawy , Yonatan Kahn

Data assimilation methods aim at estimating the state of a system by combining observations with a physical model. When sequential data assimilation is considered, the joint distribution of the latent state and the observations is described…

Methodology · Statistics 2018-04-23 Thi Tuyet Trang Chau , Pierre Ailliot , Valérie Monbet , Pierre Tandeo

We demonstrate how the mixed dynamic form factor (MDFF) can be interpreted as a quadratic form. This makes it possible to use matrix diagonalization methods to reduce the number of terms that need to be taken into account when calculating…

Materials Science · Physics 2017-02-16 Stefan Löffler , Viktoria Motsch , Peter Schattschneider

In this paper, different strands of literature are combined in order to obtain algorithms for semi-parametric estimation of discrete choice models that include the modelling of unobserved heterogeneity by using mixing distributions for the…

Methodology · Statistics 2022-12-12 Dietmar Bauer , Sebastian Büscher , Manuel Batram

We apply a recently developed framework for analyzing the convergence of stochastic algorithms to the general problem of large-scale nonconvex composite optimization more generally, and nonconvex likelihood maximization in particular. Our…

Optimization and Control · Mathematics 2024-01-25 D. Russell Luke , Steffen Schultze , Helmut Grubmüller

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

Invariance to nuisance transformations is one of the desirable properties of effective representations. We consider transformations that form a \emph{group} and propose an approach based on kernel methods to derive local group invariant…

Machine Learning · Computer Science 2017-05-25 Anant Raj , Abhishek Kumar , Youssef Mroueh , P. Thomas Fletcher , Bernhard Schölkopf

Approximating a probability distribution using a set of particles is a fundamental problem in machine learning and statistics, with applications including clustering and quantization. Formally, we seek a weighted mixture of Dirac measures…

Machine Learning · Statistics 2026-04-24 Ayoub Belhadji , Daniel Sharp , Youssef Marzouk

Normalizing flows are objects used for modeling complicated probability density functions, and have attracted considerable interest in recent years. Many flexible families of normalizing flows have been developed. However, the focus to date…

Methodology · Statistics 2023-01-18 Tin Lok James Ng , Andrew Zammit-Mangion

Recent advances in image clustering typically focus on learning better deep representations. In contrast, we present an orthogonal approach that does not rely on abstract features but instead learns to predict image transformations and…

Computer Vision and Pattern Recognition · Computer Science 2020-10-29 Tom Monnier , Thibault Groueix , Mathieu Aubry

We rigorously quantify the improvement in the sample complexity of variational divergence estimations for group-invariant distributions. In the cases of the Wasserstein-1 metric and the Lipschitz-regularized $\alpha$-divergences, the…

Statistics Theory · Mathematics 2024-11-26 Ziyu Chen , Markos A. Katsoulakis , Luc Rey-Bellet , Wei Zhu

The stochastic block model (SBM) is a mixture model used for the clustering of nodes in networks. It has now been employed for more than a decade to analyze very different types of networks in many scientific fields such as Biology and…

Methodology · Statistics 2014-05-12 E. Côme , P. Latouche

Mixture modelling using elliptical distributions promises enhanced robustness, flexibility and stability over the widely employed Gaussian mixture model (GMM). However, existing studies based on the elliptical mixture model (EMM) are…

Machine Learning · Computer Science 2020-09-30 Shengxi Li , Zeyang Yu , Danilo Mandic

Finite mixtures of regressions with fixed covariates are a commonly used model-based clustering methodology to deal with regression data. However, they assume assignment independence, i.e. the allocation of data points to the clusters is…

Methodology · Statistics 2021-04-27 Salvatore D. Tomarchio , Paul D. McNicholas , Antonio Punzo

It is often of interest to perform clustering on longitudinal data, yet it is difficult to formulate an intuitive model for which estimation is computationally feasible. We propose a model-based clustering method for clustering objects that…

Methodology · Statistics 2020-05-19 Daniel K. Sewell , Yuguo Chen , William Bernhard , Tracy Sulkin

We consider in this paper the semiparametric mixture of two distributions equal up to a shift parameter. The model is said to be semiparametric in the sense that the mixed distribution is not supposed to belong to a parametric family. In…

Statistics Theory · Mathematics 2011-11-10 Cristina Butucea , Pierre Vandekerkhove

The Expectation-Maximization (EM) algorithm for mixture models often results in slow or invalid convergence. The popular convergence proof affirms that the likelihood increases with Q; Q is increasing in the M -step and non-decreasing in…

Machine Learning · Computer Science 2018-10-29 Chenguang Lu

Although various clustering methods have been successfully applied to polarimetric synthetic aperture radar (PolSAR) image clustering tasks, most of the available approaches fail to realize automatic determination of cluster number, nor…

Image and Video Processing · Electrical Eng. & Systems 2021-04-06 Shijie Ren , Feng Zhou , Changlong Wang
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