Summary. The paper is concerned with inference based on the mean function of a functional time series. We develop a normal approximation for the functional sample mean and then focus on the estimation of the asymptotic variance kernel. Using these results, we develop and asymptotically justify testing procedures for the equality of means in two functional samples exhibiting temporal dependence. Evaluated by means of a simulation study and application to a real data set, these two-sample procedures enjoy good size and power in finite samples.

Estimation of the mean of functional time series and a two-sample problem

Functional regression allows for a scalar response to be dependent on a functional predictor; however, not much work has been done when response variables are dependence spatial variables. In this paper, we introduce a new partial functional linear spatial autoregressive model which explores the relationship between a scalar dependence spatial response variable and explanatory variables containing both multiple real-valued scalar variables and a function-valued random variable. By means of functional principal components analysis and the instrumental variable estimation method, we obtain the estimators of the parametric component and slope function of the model. Under some regularity conditions, we establish the asymptotic normality for the parametric component and the convergence rate for slope function. At last, we illustrate the finite sample performance of our proposed methods with some simulation studies.

https://www.mdpi.com/2227-7390/8/10/1680/pdf

Estimation in Partial Functional Linear Spatial Autoregressive Model

In this article, we consider a new robust estimation procedure for the partial functional linear model (PFLM) with the slope function approximated by spline basis functions. This robust estimation procedure applies a modified Huber’s function with tail function replaced by the exponential squared loss (ESL) to achieve robustness against outliers. A data-driven procedure is presented for selecting the tuning parameters of the new estimation method, which enables us to reach better robustness and efficiency than other methods in the presence of outliers or non-normal errors. We construct robust estimators of both parametric coefficients and function coefficient in the PFLM. Moreover, some asymptotic properties of the resulting estimators are established. The finite sample performance of our proposed method is studied through simulations and illustrated with a data example.

Robust estimation with a modified Huber’s loss for partial functional linear models based on splines

We consider the estimation and hypothesis test for single-index model by proposing a profile mean squares relative error estimation method, coupling with a leave-one-component-out method. The asymp...

Single-index relative error regression models

Functional regression with dependent error and missing observation in reproducing kernel Hilbert spaces

Skew-normal partial functional linear model and homogeneity test

Estimation in functional single-index varying coefficient model

This paper proposes tests for the null of sphericity and identity matrix for nonparametric time-varying coefficient panel data models with fixed effects. Firstly, based on the local linear smoothing technique, the estimators of the unknown coefficient functions and model residuals are obtained. Secondly, proper test statistics are proposed aiming at tests for sphericity or identity matrix with a large number of cross-sectional units and time series observations. In addition, the limiting distributions of the proposed test statistics are derived based on random matrix theory. At last, some simulation studies are conducted to examine the finite sample performance for the proposed test statistics and a real data example is analyzed.

Yuping Hu

Papers

Skew-normal partial functional linear model and homogeneity test

Estimation in functional single-index varying coefficient model

Test for the covariance matrix in time-varying coefficients panel data models with fixed effects

Statistical inference of varying-coefficient partial functional spatial autoregressive model