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Identifying an appropriate covariance function is one of the primary interests in spatial and spatio-temporal statistics because it allows researchers to analyze the dependence structure of the random process. For this purpose, spatial…

Methodology · Statistics 2025-02-04 Jongwook Kim , Chunfeng Huang , Nicholas Bussberg

This paper proposes stochastic models for the analysis of ocean surface trajectories obtained from freely-drifting satellite-tracked instruments. The proposed time series models are used to summarise large multivariate datasets and infer…

Applications · Statistics 2017-03-16 Adam M. Sykulski , Sofia C. Olhede , Jonathan M. Lilly , Eric Danioux

Self-supervised learning has garnered increasing attention in time series analysis for benefiting various downstream tasks and reducing reliance on labeled data. Despite its effectiveness, existing methods often struggle to comprehensively…

Machine Learning · Computer Science 2025-06-12 Daoyu Wang , Mingyue Cheng , Zhiding Liu , Qi Liu

Multivariate spatial-statistical models are often used when modeling environmental and socio-demographic processes. The most commonly used models for multivariate spatial covariances assume both stationarity and symmetry for the…

Methodology · Statistics 2021-05-11 Quan Vu , Andrew Zammit-Mangion , Noel Cressie

In this paper, we consider the coefficient-based regularized distribution regression which aims to regress from probability measures to real-valued responses over a reproducing kernel Hilbert space (RKHS), where the regularization is put on…

Machine Learning · Statistics 2022-08-29 Yuan Mao , Lei Shi , Zheng-Chu Guo

We introduce a new numerical method for solving time-harmonic acoustic scattering problems. The main focus is on plane waves scattered by smoothly varying material inhomogeneities. The proposed method works for any frequency $\omega$, but…

Numerical Analysis · Mathematics 2022-01-14 Anton Arnold , Sjoerd Geevers , Ilaria Perugia , Dmitry Ponomarev

Hierarchical forecasting is a key problem in many practical multivariate forecasting applications - the goal is to simultaneously predict a large number of correlated time series that are arranged in a pre-specified aggregation hierarchy.…

Machine Learning · Computer Science 2021-10-13 Biswajit Paria , Rajat Sen , Amr Ahmed , Abhimanyu Das

We observe two sequences of curve which are connected via an integral operator. Our model includes linear models as well as autoregressive models in Hilbert spaces. We wish to test the null hypothesis that the operator did not change during…

Statistics Theory · Mathematics 2012-02-07 Lajos Horvath , Ron Reeder

Context: Helioseismic analysis of large-scale flows and structural inhomogeneities in the Sun requires the computation of sensitivity kernels that account for the spherical geometry of the Sun, as well as systematic effects such as…

Solar and Stellar Astrophysics · Physics 2021-12-28 Jishnu Bhattacharya

In this paper we employ methods from Statistical Mechanics to model temporal correlations in time series. We put forward a methodology based on the Maximum Entropy principle to generate ensembles of time series constrained to preserve part…

Statistical Mechanics · Physics 2020-07-15 Riccardo Marcaccioli , Giacomo Livan

This work is concerned with the study of the adaptivity properties of nonparametric regression estimators over the $d$-dimensional sphere within the global thresholding framework. The estimators are constructed by means of a form of…

Statistics Theory · Mathematics 2016-07-27 Claudio Durastanti

New spherical scalar modes on the expanding part of Sitter spacetime, eigenfunctions of a conserved Hamiltonian-like operator are found by solving the Klein-Gordon equation in the appropriate coordinate chart, with the help of a time…

General Relativity and Quantum Cosmology · Physics 2012-09-24 Gabriel Pascu

In this work, we propose \texttt{TimeGrad}, an autoregressive model for multivariate probabilistic time series forecasting which samples from the data distribution at each time step by estimating its gradient. To this end, we use diffusion…

Machine Learning · Computer Science 2021-07-09 Kashif Rasul , Calvin Seward , Ingmar Schuster , Roland Vollgraf

A significantly low cost and tractable progressive learning approach is proposed and discussed for efficient spatiotemporal monitoring of a completely unknown, two dimensional correlated signal distribution in localized wireless sensor…

Signal Processing · Electrical Eng. & Systems 2020-01-08 Hadi Alasti

Autoregressive surrogate models (or \textit{emulators}) of spatiotemporal systems provide an avenue for fast, approximate predictions, with broad applications across science and engineering. At inference time, however, these models are…

Machine Learning · Computer Science 2025-07-10 Chris Pedersen , Laure Zanna , Joan Bruna

Time series modeling is a well-established problem, which often requires that methods (1) expressively represent complicated dependencies, (2) forecast long horizons, and (3) efficiently train over long sequences. State-space models (SSMs)…

Machine Learning · Computer Science 2023-03-17 Michael Zhang , Khaled K. Saab , Michael Poli , Tri Dao , Karan Goel , Christopher Ré

The forecast on a time scale of 1 or 2 hours is crucial for all kind of new generation facilities (ELTs) instrumentation supported by the adaptive optics that will be mainly operated in Service Mode. In a recent study (Masciadri et al.…

Instrumentation and Methods for Astrophysics · Physics 2023-08-08 Elena Masciadri , Alessio Turchi , Luca Fini

Multivariate time series forecasting with hierarchical structure is pervasive in real-world applications, demanding not only predicting each level of the hierarchy, but also reconciling all forecasts to ensure coherency, i.e., the forecasts…

Machine Learning · Computer Science 2025-03-04 Shiyu Wang , Fan Zhou , Yinbo Sun , Lintao Ma , James Zhang , Yangfei Zheng

Spatially distributed functional data are prevalent in many statistical applications such as meteorology, energy forecasting, census data, disease mapping, and neurological studies. Given their complex and high-dimensional nature,…

Statistics Theory · Mathematics 2024-02-06 Suneel Babu Chatla , Ruiqi Liu

We develop a skew-adaptive extension of split conformal prediction for regression. The method starts from an asymmetric interval family centered at a point prediction and uses the gauge approach to deduce the conformity score induced by…

Machine Learning · Statistics 2026-05-18 Paulo C. Marques F. , Helton Graziadei