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Regression analysis with missing data is a long-standing and challenging problem, particularly when there are many missing variables with arbitrary missing patterns. Likelihood-based methods, although theoretically appealing, are often…

Methodology · Statistics 2024-10-16 Ngok Sang Kwok , Kin Yau Wong

When facing multivariate covariates, general semiparametric regression techniques come at hand to propose flexible models that are unexposed to the curse of dimensionality. In this work a semiparametric copula-based estimator for…

Methodology · Statistics 2016-03-25 Mickael De Backer , Anouar El Ghouch , Ingrid Van Keilegom

In this paper, we observe a sparse mean vector through Gaussian noise and we aim at estimating some additive functional of the mean in the minimax sense. More precisely, we generalize the results of (Collier et al., 2017, 2019) to a very…

Statistics Theory · Mathematics 2019-08-30 Olivier Collier , Laëtitia Comminges

We study the covariate shift problem in the context of nonparametric regression over a reproducing kernel Hilbert space (RKHS). We focus on two natural families of covariate shift problems defined using the likelihood ratios between the…

Statistics Theory · Mathematics 2023-06-07 Cong Ma , Reese Pathak , Martin J. Wainwright

Cox's proportional hazards model is one of the most popular statistical models to evaluate associations of exposure with a censored failure time outcome. When confounding factors are not fully observed, the exposure hazard ratio estimated…

Methodology · Statistics 2022-01-04 Linbo Wang , Eric Tchetgen Tchetgen , Torben Martinussen , Stijn Vansteelandt

In this paper, we consider the problem of estimating the eigenvalues and eigenfunctions of the covariance kernel (i.e., the functional principal components) from sparse and irregularly observed longitudinal data. We approach this problem…

Methodology · Statistics 2007-10-30 Jie Peng , Debashis Paul

The present article is devoted to the semi-parametric estimation of multivariate expectiles for extreme levels. The considered multivariate risk measures also include the possible conditioning with respect to a functional covariate,…

Statistics Theory · Mathematics 2023-03-30 Elena Di Bernardino , Thomas Laloë , Cambyse Pakzad

The Cox proportional hazards model is ubiquitous in the analysis of time-to-event data. However, when the data dimension p is comparable to the sample size $N$, maximum likelihood estimates for its regression parameters are known to be…

Methodology · Statistics 2020-01-08 M Sheikh , A. C. C. Coolen

We study the asymptotic behaviour of the Regularized Maximum Partial Likelihood Estimator (RMPLE) in the proportional limit, considering an arbitrary convex regularizer and assuming that the covariates $\mathbf{X}_i\in\mathbb{R}^{p}$ follow…

Statistics Theory · Mathematics 2025-02-07 Emanuele Massa , Anthony Coolen

We consider covariance parameter estimation for Gaussian processes with functional inputs. From an increasing-domain asymptotics perspective, we prove the asymptotic consistency and normality of the maximum likelihood estimator. We extend…

Statistics Theory · Mathematics 2024-05-16 Lucas Reding , Andrés F. López-Lopera , François Bachoc

We consider the estimation of the value of a linear functional of the slope parameter in functional linear regression, where scalar responses are modeled in dependence of random functions. In Johannes and Schenk [2010] it has been shown…

Statistics Theory · Mathematics 2011-12-14 Jan Johannes , Rudolf Schenk

We study the minimax estimation of covariance eigenfunctions and eigenvalues in functional principal component analysis when $n$ trajectories are observed at $p$ common grid points with additive noise. We consider covariance kernels with…

Statistics Theory · Mathematics 2026-05-08 Nassim Bourarach , Franck Picard , Vincent Rivoirard , Angelina Roche

This work is concerned with the estimation of multidimensional regression and the asymptotic behaviour of the test involved in selecting models. The main problem with such models is that we need to know the covariance matrix of the noise to…

Statistics Theory · Mathematics 2008-02-20 Joseph Rynkiewicz

The asymptotic variance of the maximum likelihood estimate is proved to decrease when the maximization is restricted to a subspace that contains the true parameter value. Maximum likelihood estimation allows a systematic fitting of…

Statistics Theory · Mathematics 2018-01-31 Marie Turčičová , Jan Mandel , Kryštof Eben

We consider a class of semiparametric regression models which are one-parameter extensions of the Cox [J. Roy. Statist. Soc. Ser. B 34 (1972) 187-220] model for right-censored univariate failure times. These models assume that the hazard…

Statistics Theory · Mathematics 2007-06-13 Michael R. Kosorok , Bee Leng Lee , Jason P. Fine

We consider functional linear regression models where functional outcomes are associated with scalar predictors by coefficient functions with shape constraints, such as monotonicity and convexity, that apply to sub-domains of interest. To…

Methodology · Statistics 2025-05-09 Kyunghee Han , Yeonjoo Park , Soo-Young Kim

In the common partially linear single-index model we establish a Bahadur representation for a smoothing spline estimator of all model parameters and use this result to prove the joint weak convergence of the estimator of the index link…

Statistics Theory · Mathematics 2024-07-03 Jiajun Tang , Holger Dette

We consider estimation of a sparse parameter vector that determines the covariance matrix of a Gaussian random vector via a sparse expansion into known "basis matrices". Using the theory of reproducing kernel Hilbert spaces, we derive lower…

Information Theory · Computer Science 2011-01-21 Alexander Jung , Sebastian Schmutzhard , Franz Hlawatsch , Alfred O. Hero

In Huntington's disease research, a current goal is to understand how symptoms change prior to a clinical diagnosis. Statistically, this entails modeling symptom severity as a function of the covariate 'time until diagnosis', which is often…

Methodology · Statistics 2024-09-19 Seong-ho Lee , Brian D. Richardson , Yanyuan Ma , Karen S. Marder , Tanya P. Garcia

Robust estimation has played an important role in statistical and machine learning. However, its applications to functional linear regression are still under-developed. In this paper, we focus on Huber's loss with a diverging robustness…

Statistics Theory · Mathematics 2024-09-18 Ling Peng , Xiaohui Liu , Heng Lian