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We present a method for converting a time record of turbulent velocity measured at a point in a flow to a spatial velocity record consisting of consecutive convection elements. The spatial record allows computation of dynamic statistical…

Fluid Dynamics · Physics 2019-06-18 Preben Buchhave , Clara M. Velte

In this note we show that the locally stationary wavelet process can be decomposed into a sum of signals, each of which following a moving average process with time-varying parameters. We then show that such moving average processes are…

Methodology · Statistics 2009-01-27 K. Triantafyllopoulos , G. P. Nason

Max-stable processes are natural models for spatial extremes because they provide suitable asymptotic approximations to the distribution of maxima of random fields. In the recent past, several parametric families of stationary max-stable…

Methodology · Statistics 2016-02-22 Raphael Huser , Marc G. Genton

We propose a variational method to solve all three estimation problems for nonlinear stochastic dynamical systems: prediction, filtering, and smoothing. Our new approach is based upon a proper choice of cost function, termed the {\it…

Data Analysis, Statistics and Probability · Physics 2007-05-23 Gregory L. Eyink

The importance of modelling temperature fields goes beyond the need to understand a region's climate and serves too as a starting point for understanding their socioeconomic, and health consequences. The topography of the study region…

Applications · Statistics 2016-04-05 Camila M. Casquilho-Resende , Nhu D. Le , James V. Zidek

This paper introduces a data-driven time embedding method for modeling long-range seasonal dependencies in spatiotemporal forecasting tasks. The proposed approach employs Dynamic Mode Decomposition (DMD) to extract temporal modes directly…

Machine Learning · Computer Science 2025-08-05 Menglin Kong , Vincent Zhihao Zheng , Xudong Wang , Lijun Sun

This article presents an original methodology for the prediction of steady turbulent aerodynamic fields. Due to the important computational cost of high-fidelity aerodynamic simulations, a surrogate model is employed to cope with the…

Fluid Dynamics · Physics 2019-12-05 Romain Dupuis , Jean-Christophe Jouhaud , Pierre Sagaut

In this paper, modulating functions-based method is proposed for estimating space-time dependent unknowns in one-dimensional partial differential equations. The proposed method simplified the problem into a system of algebraic equations…

Numerical Analysis · Mathematics 2016-01-13 Sharefa Asiri , Taous-Meriem Laleg-Kirati

We present a variational method which uses a quartic exponential function as a trial wave-function to describe time-dependent quantum mechanical systems. We introduce a new physical variable $y$ which is appropriate to describe the shape of…

High Energy Physics - Theory · Physics 2009-11-07 Hyeong-Chan Kim , Jae Hyung Yee

Multivariate locally stationary functional time series provide a flexible framework for modeling complex data structures exhibiting both temporal and spatial dependencies while allowing for time-varying data generating mechanism. In this…

Methodology · Statistics 2025-01-15 Lujia Bai , Holger Dette , Weichi Wu

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 develop a timescale synthesis-based probabilistic approach for the modeling of locally stationary signals. Inspired by our previous work, the model involves zero-mean, complex Gaussian wavelet coefficients, whose distribution varies as a…

Statistics Theory · Mathematics 2020-02-10 Adrien Meynard , Bruno Torrésani

We propose a spatio-temporal data-fusion framework for point data and gridded data with variables observed on different spatial supports. A latent Gaussian field with a Mat\'ern-SPDE prior provides a continuous space representation, while…

Methodology · Statistics 2025-11-19 Weiyue Zheng , Andrew Elliott , Claire Miller , Marian Scott

Electromagnetic waves in a system with a space and time dependent boundary experience both diffraction and Doppler-like frequency conversion. In order to analyse such situations, conventional methods call for either the eigenmodes or the…

Optics · Physics 2021-07-14 Daigo Oue , Kun Ding , J. B. Pendry

In this paper we propose a nonparametric procedure for validating the assumption of stationarity in multivariate locally stationary time series models. We develop a bootstrap assisted test based on a Kolmogorov-Smirnov type statistic, which…

Statistics Theory · Mathematics 2013-12-06 Ruprecht Puchstein , Philip Preuß

Nonlinear regression is a useful statistical tool, relating observed data and a nonlinear function of unknown parameters. When the parameter-dependent nonlinear function is computationally intensive, a straightforward regression analysis by…

Applications · Statistics 2009-01-26 Dorin Drignei , Chris E. Forest , Doug Nychka

Spatial concurrent linear models, in which the model coefficients are spatial processes varying at a local level, are flexible and useful tools for analyzing spatial data. One approach places stationary Gaussian process priors on the…

Applications · Statistics 2012-02-03 Zuofeng Shang , Murray K. Clayton

Studying sample path behaviour of stochastic fields/processes is a classical research topic in probability theory and related areas such as fractal geometry. To this end, many methods have been developed since a long time in Gaussian…

Probability · Mathematics 2016-06-13 Antoine Ayache , Geoffrey Boutard

Based on a novel dynamic Whittle likelihood approximation for locally stationary processes, a Bayesian nonparametric approach to estimating the time-varying spectral density is proposed. This dynamic frequency-domain based likelihood…

Methodology · Statistics 2023-03-22 Yifu Tang , Claudia Kirch , Jeong Eun Lee , Renate Meyer

In this work we present full Bayesian inference for a new flexible nonseparable class of cross-covariance functions for multivariate spatial data. A Bayesian test is proposed for separability of covariance functions which is much more…

Methodology · Statistics 2017-07-24 Rafael S. Erbisti , Thais C. O. Fonseca , Mariane B. Alves