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In multivariate functional data analysis, different functional covariates often exhibit homogeneity. The covariates with pronounced homogeneity can be analyzed jointly within the same group, offering a parsimonious approach to modeling…

Methodology · Statistics 2024-10-24 Shuhao Jiao , Ngai-Hang Chan

We consider nonparametric estimation of the mean and covariance functions for functional/longitudinal data. Strong uniform convergence rates are developed for estimators that are local-linear smoothers. Our results are obtained in a unified…

Statistics Theory · Mathematics 2012-11-12 Yehua Li , Tailen Hsing

Correlated random fields are a common way to model dependence struc- tures in high-dimensional data, especially for data collected in imaging. One important parameter characterizing the degree of dependence is the asymp- totic variance…

Statistics Theory · Mathematics 2018-03-20 Annabel Prause , Ansgar Steland

The RV coefficient measures the similarity between two multivariate configurations, and its significance testing has attracted various proposals in the last decades. We present a new approach, the invariant orthogonal integration,…

Statistics Theory · Mathematics 2022-10-04 François Bavaud

In this paper, we consider the problem of estimating the covariance kernel and its eigenvalues and eigenfunctions from sparse, irregularly observed, noise corrupted and (possibly) correlated functional data. We present a method based on…

Methodology · Statistics 2008-07-09 Debashis Paul , Jie Peng

Getting tools that allow simple representations and comparisons of a set of categorical trajectories is of major interest for statisticians. Without loosing any information, we associate to each state a binary random indicator function,…

Methodology · Statistics 2026-05-05 Hervé Cardot , Caroline Peltier

In this paper, we develop a multi-step estimation procedure to simultaneously estimate the varying-coefficient functions using a local-linear generalized method of moments (GMM) based on continuous moment conditions. To incorporate spatial…

Methodology · Statistics 2024-10-07 Pratim Guha Niyogi , Ping-Shou Zhong , Xiaohong Joe Zhou

Moving from univariate to bivariate jointly dependent long-memory time series introduces a phase parameter $(\gamma)$, at the frequency of principal interest, zero; for short-memory series $\gamma=0$ automatically. The latter case has also…

Statistics Theory · Mathematics 2008-11-07 P. M. Robinson

We consider nonparametric estimation of a covariance function on the unit square, given a sample of discretely observed fragments of functional data. When each sample path is only observed on a subinterval of length $\delta<1$, one has no…

Methodology · Statistics 2018-10-05 Marie-Hélène Descary , Victor M. Panaretos

We propose generalized additive partial linear models for complex data which allow one to capture nonlinear patterns of some covariates, in the presence of linear components. The proposed method improves estimation efficiency and increases…

Statistics Theory · Mathematics 2014-05-26 Li Wang , Lan Xue , Annie Qu , Hua Liang

Registration of multivariate functional data involves handling of both cross-component and cross-observation phase variations. Allowing for the two phase variations to be modelled as general diffeomorphic time warpings, in this work we…

Methodology · Statistics 2022-07-25 Xiaohan Guo , Sebastian Kurtek , Karthik Bharath

A nonparametric regression setting is considered with a real-valued covariate and responses from a metric space. One may approach this setting via Fr\'echet regression, where the value of the regression function at each point is estimated…

Statistics Theory · Mathematics 2022-05-17 Christof Schötz

We propose a new nonparametric procedure for the detection and estimation of multiple structural breaks in the autocovariance function of a multivariate (second- order) piecewise stationary process, which also identifies the components of…

Statistics Theory · Mathematics 2013-09-06 Philip Preuß , Ruprecht Puchstein , Holger Dette

It is common in machine learning and statistics to use symmetries derived from expert knowledge to simplify problems or improve performance, using methods like data augmentation or penalties. In this paper we consider the unsupervised and…

Machine Learning · Computer Science 2022-04-05 Colin Hagemeyer

We study the problem of change point localisation and inference for sequentially collected fragmented functional data, where each curve is observed only over discrete grids randomly sampled over a short fragment. The sequence of underlying…

Methodology · Statistics 2024-05-10 Gengyu Xue , Haotian Xu , Yi Yu

Flexible modelling of the autocovariance function (ACF) is central to time-series, spatial, and spatio-temporal analysis. Modern applications often demand flexibility beyond classical parametric models, motivating non-parametric…

Methodology · Statistics 2025-06-30 Lachlan Astfalck

Functional linear regression analysis aims to model regression relations which include a functional predictor. The analog of the regression parameter vector or matrix in conventional multivariate or multiple-response linear regression…

Statistics Theory · Mathematics 2011-02-28 Yichao Wu , Jianqing Fan , Hans-Georg Müller

Metric-affine theories of gravity provide an interesting alternative to General Relativity: in such an approach, the metric and the affine (not necessarily symmetric) connection are independent quantities. Furthermore, the action should…

General Relativity and Quantum Cosmology · Physics 2012-11-08 Vincenzo Vitagliano , Thomas P. Sotiriou , Stefano Liberati

We propose an independence test for random variables valued into metric spaces by using a test statistic obtained from appropriately centering and rescaling the squared Hilbert-Schmidt norm of the usual empirical estimator of normalized…

Statistics Theory · Mathematics 2022-11-11 Terence Kevin Manfoumbi Djonguet , Guy Martial Nkiet

Modern recording techniques enable neuroscientists to simultaneously study neural activity across large populations of neurons, with capturing predictor-dependent correlations being a fundamental challenge in neuroscience. Moreover, the…

Applications · Statistics 2025-02-04 Ganchao Wei