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Gaussian processes (GPs) are frequently used in machine learning and statistics to construct powerful models. However, when employing GPs in practice, important considerations must be made, regarding the high computational burden,…

Computation · Statistics 2021-03-08 Karla Monterrubio-Gómez , Sara Wade

Covariance matrix estimation is an important problem in multivariate data analysis, both from theoretical as well as applied points of view. Many simple and popular covariance matrix estimators are known to be severely affected by model…

Methodology · Statistics 2025-11-21 Soumya Chakraborty , Ayanendranath Basu , Abhik Ghosh

We investigate the problem of estimating the structure factor, or spectra, of stationary spatial point processes. In the first part, we establish a minimax lower bound for this estimation problem, using an approach tailored to second-order…

Statistics Theory · Mathematics 2025-11-19 Gabriel Mastrilli

The existing contrastive learning methods mainly focus on single-grained representation learning, e.g., part-level, object-level or scene-level ones, thus inevitably neglecting the transferability of representations on other granularity…

Computer Vision and Pattern Recognition · Computer Science 2024-07-03 Chengchao Shen , Jianzhong Chen , Jianxin Wang

Point pattern data often exhibit features such as abrupt changes, hotspots and spatially varying dependence in local intensity. Under a Poisson process framework, these correspond to discontinuities and nonstationarity in the underlying…

Methodology · Statistics 2025-07-24 Izabel Nolau , Flávio B. Gonçalves , Dani Gamerman

We proposed a semi-parametric estimation procedure in order to estimate the parameters of a max-mixture model and also of a max-stable model (inverse max-stable model) as an alternative to composite likelihood. A good estimation by the…

Statistics Theory · Mathematics 2017-12-06 M. Ahmed , V Maume-Deschamps , P. Ribereau , C. Vial

In this paper we propose simple multiscale basis functions with constraint energy minimization to solve elliptic problems with high contrast medium. Our methodology is based on the recently developed non-local multicontinuum method (NLMC).…

Numerical Analysis · Mathematics 2019-04-26 Lina Zhao , Eric T. Chung

We develop a multi-level restricted Gaussian maximum likelihood method for estimating the covariance function parameters and computing the best unbiased predictor. Our approach produces a new set of multi-level contrasts where the…

Computation · Statistics 2016-03-29 Julio E. Castrillon-Candas , Marc G. Genton , Rio Yokota

In various practical situations, we encounter data from stochastic processes which can be efficiently modelled by an appropriate parametric model for subsequent statistical analyses. Unfortunately, the most common estimation and inference…

Methodology · Statistics 2022-04-12 Rohan Hore , Abhik Ghosh

The Minimum Covariance Determinant (MCD) approach robustly estimates the location and scatter matrix using the subset of given size with lowest sample covariance determinant. Its main drawback is that it cannot be applied when the dimension…

Methodology · Statistics 2021-01-13 Kris Boudt , Peter J. Rousseeuw , Steven Vanduffel , Tim Verdonck

We introduce a new micro-macro Markov chain Monte Carlo method (mM-MCMC) to sample invariant distributions of molecular dynamics systems that exhibit a time-scale separation between the microscopic (fast) dynamics, and the macroscopic…

Numerical Analysis · Mathematics 2020-02-24 Hannes Vandecasteele , Giovanni Samaey

We propose a mini-batching scheme for improving the theoretical complexity and practical performance of semi-stochastic gradient descent applied to the problem of minimizing a strongly convex composite function represented as the sum of an…

Machine Learning · Computer Science 2014-10-20 Jakub Konečný , Jie Liu , Peter Richtárik , Martin Takáč

We develop a method to combine Markov chain Monte Carlo (MCMC) and variational inference (VI), leveraging the advantages of both inference approaches. Specifically, we improve the variational distribution by running a few MCMC steps. To…

Machine Learning · Statistics 2019-05-29 Francisco J. R. Ruiz , Michalis K. Titsias

Statistical inference methods are fundamentally important in machine learning. Most state-of-the-art inference algorithms are variants of Markov chain Monte Carlo (MCMC) or variational inference (VI). However, both methods struggle with…

Machine Learning · Computer Science 2019-10-17 Yichuan Zhang , José Miguel Hernández-Lobato

Learning-based multi-view stereo (MVS) methods have made impressive progress and surpassed traditional methods in recent years. However, their accuracy and completeness are still struggling. In this paper, we propose a new method to enhance…

Computer Vision and Pattern Recognition · Computer Science 2022-06-22 Yikang Ding , Zhenyang Li , Dihe Huang , Zhiheng Li , Kai Zhang

Gaussian Process (GP) models are a powerful and flexible tool for non-parametric regression and classification. Computation for GP models is intensive, since computing the posterior density, $\pi$, for covariance function parameters…

Computation · Statistics 2013-05-13 Chunyi Wang , Radford M. Neal

The Minimum Covariance Determinant (MCD) method is a highly robust estimator of multivariate location and scatter, for which a fast algorithm is available. Since estimating the covariance matrix is the cornerstone of many multivariate…

Methodology · Statistics 2021-01-13 Mia Hubert , Michiel Debruyne , Peter J. Rousseeuw

The aim of this paper is to approximate a finite-state Markov process by another process with fewer states, called herein the approximating process. The approximation problem is formulated using two different methods. The first method,…

We propose a new stochastic coordinate descent method for minimizing the sum of convex functions each of which depends on a small number of coordinates only. Our method (APPROX) is simultaneously Accelerated, Parallel and PROXimal; this is…

Optimization and Control · Mathematics 2014-03-04 Olivier Fercoq , Peter Richtárik

Standard contrastive learning approaches usually require a large number of negatives for effective unsupervised learning and often exhibit slow convergence. We suspect this behavior is due to the suboptimal selection of negatives used for…

Machine Learning · Computer Science 2021-12-22 Anshul Shah , Suvrit Sra , Rama Chellappa , Anoop Cherian