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Covariance functions are the core of spatial statistics, stochastic processes, machine learning as well as many other theoretical and applied disciplines. The properties of the covariance function at small and large distances determine the…

Statistics Theory · Mathematics 2023-01-16 Alfredo Alegría , Fabián Ramírez , Emilio Porcu

This work addresses the problem of simulating Gaussian random fields that are continuously indexed over a class of metric graphs, termed graphs with Euclidean edges, being more general and flexible than linear networks. We introduce three…

Statistics Theory · Mathematics 2024-04-29 Alfredo Alegría , Xavier Emery , Tobia Filosi , Emilio Porcu

Variational approximation methods have proven to be useful for scaling Bayesian computations to large data sets and highly parametrized models. Applying variational methods involves solving an optimization problem, and recent research in…

Methodology · Statistics 2017-01-13 Victor M. -H. Ong , David J. Nott , Michael S. Smith

We study the nonparametric covariance estimation of a stationary Gaussian field X observed on a regular lattice. In the time series setting, some procedures like AIC are proved to achieve optimal model selection among autoregressive models.…

Statistics Theory · Mathematics 2009-09-02 Nicolas Verzelen

Designing a covariance function that represents the underlying correlation is a crucial step in modeling complex natural systems, such as climate models. Geospatial datasets at a global scale usually suffer from non-stationarity and…

Machine Learning · Statistics 2015-07-10 Chintan A. Dalal , Vladimir Pavlovic , Robert E. Kopp

Analyzing massive spatial datasets using Gaussian process model poses computational challenges. This is a problem prevailing heavily in applications such as environmental modeling, ecology, forestry and environmental heath. We present a…

Methodology · Statistics 2021-12-07 Suman Majumder , Yawen Guan , Brian J. Reich , Arvind K. Saibaba

We study the nonparametric covariance estimation of a stationary Gaussian field X observed on a lattice. To tackle this issue, a neighborhood selection procedure has been recently introduced. This procedure amounts to selecting a…

Statistics Theory · Mathematics 2009-09-02 Nicolas Verzelen

For multivariate spatial Gaussian process (GP) models, customary specifications of cross-covariance functions do not exploit relational inter-variable graphs to ensure process-level conditional independence among the variables. This is…

Methodology · Statistics 2021-11-19 Debangan Dey , Abhirup Datta , Sudipto Banerjee

Many applications of Gaussian random fields and Gaussian random processes are limited by the computational complexity of evaluating the probability density function, which involves inverting the relevant covariance matrix. In this work, we…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-26 Theodor Bjorkmo , M. C. David Marsh

Analysis of geospatial data has traditionally been model-based, with a mean model, customarily specified as a linear regression on the covariates, and a covariance model, encoding the spatial dependence. We relax the strong assumption of…

Machine Learning · Statistics 2024-05-28 Wentao Zhan , Abhirup Datta

Gaussian Markov random fields (GMRFs) are useful in a broad range of applications. In this paper we tackle the problem of learning a sparse GMRF in a high-dimensional space. Our approach uses the l1-norm as a regularization on the inverse…

Machine Learning · Computer Science 2012-06-18 John Duchi , Stephen Gould , Daphne Koller

Physics-based covariance models provide a systematic way to construct covariance models that are consistent with the underlying physical laws in Gaussian process analysis. The unknown parameters in the covariance models can be estimated…

Computation · Statistics 2023-03-20 Yian Chen , Mihai Anitescu

We consider the problem of estimating a high-dimensional covariance matrix from a small number of observations when covariates on pairs of variables are available and the variables can have spatial structure. This is motivated by the…

In this paper, we model the dependencies among the items that are recommended to a user in a collaborative-filtering problem via a Gaussian Markov Random Field (MRF). We build upon Besag's auto-normal parameterization and pseudo-likelihood,…

Information Retrieval · Computer Science 2019-10-23 Harald Steck

We introduce a novel class of non-stationary covariance functions for random fields on linear networks that allows both the variance and the correlation range of the random field to vary spatially. The proposed covariance functions are…

Statistics Theory · Mathematics 2026-02-23 Alfredo Alegría

In this paper, we first propose a Bayesian neighborhood selection method to estimate Gaussian Graphical Models (GGMs). We show the graph selection consistency of this method in the sense that the posterior probability of the true model…

Applications · Statistics 2015-07-08 Zhixiang Lin , Tao Wang , Can Yang , Hongyu Zhao

In the last two decades, the linear model of coregionalization (LMC) has been widely used to model multivariate spatial processes. However, it can be a challenging task to conduct likelihood-based inference for such models because of the…

Methodology · Statistics 2024-12-04 Renaud Alie , David A. Stephens , Alexandra M. Schmidt

This article presents a neural network approach for estimating the covariance function of spatial Gaussian random fields defined in a portion of the Euclidean plane. Our proposal builds upon recent contributions, expanding from the purely…

Methodology · Statistics 2024-08-21 Alejandro Villazón , Alfredo Alegría , Xavier Emery

This paper considers a multivariate spatial random field, with each component having univariate marginal distributions of the skew-Gaussian type. We assume that the field is defined spatially on the unit sphere embedded in $\mathbb{R}^3$,…

Statistics Theory · Mathematics 2017-10-05 Alfredo Alegría , Sandra Caro , Moreno Bevilacqua , Emilio Porcu , Jorge Clarke

We introduce a scalable Gaussian process (GP) framework with deep product kernels for data-driven learning of parametrized spatio-temporal fields over fixed or parameter-dependent domains. The proposed framework learns a continuous…

Machine Learning · Computer Science 2026-03-03 Srinath Dama , Prasanth B. Nair