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This article introduces a non parametric warping model for functional data. When the outcome of an experiment is a sample of curves, data can be seen as realizations of a stochastic process, which takes into account the small variations…

Statistics Theory · Mathematics 2008-12-18 Jean-François Dupuy , Jean-Michel Loubes , Elie Maza

We address the challenge of estimation in the context of constant linear effect models with dense functional responses. In this framework, the conditional expectation of the response curve is represented by a linear combination of…

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

We aim to explain whether a stress memory task has a significant impact on tonal coarticulation. We contribute a novel approach to analyse tonal coarticulation in phonetics, where several f0 contours are compared with respect to their…

Applications · Statistics 2024-09-10 Valentina Masarotto , Yiya Chen

We study the distributional properties of the linear discriminant function under the assumption of normality by comparing two groups with the same covariance matrix but different mean vectors. A stochastic representation for the…

Statistics Theory · Mathematics 2017-05-09 Taras Bodnar , Stepan Mazur , Edward Ngailo , Nestor Parolya

Estimation and inference with modern longitudinal data from wearable devices, which consist of biological signals at high-frequency time points, is burdened by massive computational costs. We propose a distributed estimation and inference…

Methodology · Statistics 2023-09-13 Cole Manschot , Emily C. Hector

Our research proposes a novel method for reducing the dimensionality of functional data, specifically for the case where the response is a scalar and the predictor is a random function. Our method utilizes distance covariance, and has…

Statistics Theory · Mathematics 2023-09-26 Xing Yang , Jianjun Xu

The relative performance of competing point forecasts is usually measured in terms of loss or scoring functions. It is widely accepted that these scoring function should be strictly consistent in the sense that the expected score is…

Statistics Theory · Mathematics 2019-04-08 Tobias Fissler , Johanna F. Ziegel

We consider regression models with parametric (linear or nonlinear) regression function and allow responses to be ``missing at random.'' We assume that the errors have mean zero and are independent of the covariates. In order to estimate…

Statistics Theory · Mathematics 2009-08-24 Ursula U. Müller

Delineating the associations between images and a vector of covariates is of central interest in medical imaging studies. To tackle this problem of image response regression, we propose a novel nonparametric approach in the framework of…

Machine Learning · Statistics 2022-03-04 Daiwei Zhang , Lexin Li , Chandra Sripada , Jian Kang

This paper studies sparse covariance operator estimation for nonstationary processes with sharply varying marginal variance and small correlation lengthscale. We introduce a covariance operator estimator that adaptively thresholds the…

Statistics Theory · Mathematics 2025-06-23 Omar Al-Ghattas , Daniel Sanz-Alonso

We consider inference for the mean and covariance functions of covariate adjusted functional data using Local Linear Kernel (LLK) estimators. By means of a double asymptotic, we differentiate between sparse and dense covariate adjusted…

Methodology · Statistics 2018-02-28 Dominik Liebl

Multivariate spatial field data are increasingly common and whose modeling typically relies on building cross-covariance functions to describe cross-process relationships. An alternative viewpoint is to model the matrix of spectral…

Statistics Theory · Mathematics 2015-05-07 William Kleiber

For some estimations and predictions, we solve minimization problems with asymmetric loss functions. Usually, we estimate the coefficient of regression for these problems. In this paper, we do not make such the estimation, but rather give a…

Statistics Theory · Mathematics 2023-03-03 Naoya Yamaguchi , Yuka Yamaguchi , Ryuei Nishii

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

For covariance test in functional data analysis, existing methods are developed only for fully observed curves, whereas in practice, trajectories are typically observed discretely and with noise. To bridge this gap, we employ a…

Methodology · Statistics 2026-04-20 Yang Zhou , Jin Yang , Fang Yao

We propose an estimation approach to analyse correlated functional data which are observed on unequal grids or even sparsely. The model we use is a functional linear mixed model, a functional analogue of the linear mixed model. Estimation…

Methodology · Statistics 2015-08-10 Jona Cederbaum , Marianne Pouplier , Phil Hoole , Sonja Greven

Second-order characteristics including covariance and spectral density functions are fundamentally important for both statistical applications and theoretical analysis in functional time series. In the high-dimensional setting where the…

Statistics Theory · Mathematics 2025-12-16 Bufan Li , Xinghao Qiao , Weichi Wu , Holger Dette

We present a general principle for estimating a regression function nonparametrically, allowing for a wide variety of data filtering, for example, repeated left truncation and right censoring. Both the mean and the median regression cases…

Statistics Theory · Mathematics 2011-02-10 Oliver Linton , Enno Mammen , Jens Perch Nielsen , Ingrid Van Keilegom

This paper addresses the fundamental task of estimating covariance matrix functions for high-dimensional functional data/functional time series. We consider two functional factor structures encompassing either functional factors with scalar…

Methodology · Statistics 2025-10-28 Dong Li , Xinghao Qiao , Zihan Wang

Difference-in-differences (DiD) is a cornerstone of causal inference, yet extending it to functional outcomes is not a routine scalar generalization; rather, it entails three fundamental challenges in identification, inference, and…

Methodology · Statistics 2026-05-29 Junzhu Nie , Chengxiu Ling , Mengfei Ran