连续时间下非参数回归模型的误差密度估计

本文研究连续时间下非参数回归的误差密度估计问题，给出误差密度的一个核估计量，利用回归函数的核估计在紧区间上一致均收敛的结论证明了该统计量渐近无偏差，均方相合法，并说明了该核估计中窗宽选取的办法。     

Spline Multiscale Smoothing to Control FDR for Exploring Features of Regression Curves

SiZer (significant zero crossing of the derivatives) is a multiscale smoothing method for exploring trends, maxima, and minima in data. In this article, a regression spline version of SiZer is proposed in a nonparametric regression setting by the fiducial method. The number of knots for spline interpolation is used as the scale parameter of the new SiZer, which controls the smoothness of estimate. In the construction of the new SiZer, multiple testing adjustment is made to control the row-wise false discovery rate (FDR) of SiZer. This adjustment is appealing for exploratory data analysis and has potential to increase the power. A special map is also produced on a continuous scale using p-values to assess the significance of features. Simulations and a real data application are carried out to investigate the performance of the proposed SiZer, in which several comparisons with other existing SiZers are presented. Supplementary materials for this article are available online.     

Coverage Accuracy of Confidence Intervals in Nonparametric Regression

Point-wise confidence intervals for a nonparametric regression function with random design points are considered. The confidence intervals are those based on the traditional normal approximation and the empirical likelihood. Their coverage accuracy is assessed by developing the Edgeworth expansions for the coverage probabilities. It is shown that the empirical likelihood confidence intervals are Bartlett correctable.     

一类非参数回归函数估计的性质

设Z_(11),z_(12),…,Z_是在固定点(x_i,y_1),1≤≤n_1,1≤j≤n_2,的n_1n_2个观察值,适合模型 Z_(ij)=g(x_i,y_j)+ε_(ij),1≤i≤n_1,1≤j≤n_2。(1) 本文给出了g的一种估计并讨论了估计的性质。     

基于变系数模型的自适应分位回归方法

提出了变系数模型条件分位估计的一种新方法.变系数模型已经成为经济学、流行病学、纵向数据和医学领域处理高维数据的有力工具.该模型有助于探测数据的动态特征、降低模型偏差、避免高维灾难,同时便于解释.尽管关于变系数模型条件均值的估计已经有很多文章,但关于变系数模型条件分位的估计方面的文章相对较少.文中提出了一种有效的适应性分位回归方法来诊断出齐性邻域,进行局部自适应窗宽选择和局部线性逼近,同时给出了估计量的风险界和最优窗宽的自动选择准则.模拟研究说明了所提出估计方法的效果.     

回归系数的广义根方估计及其模拟

文献[1,2]中提出了回归系数的根方估计~(k),当回归自变量间存在复共线关系时,~(k)较回归系数的最小二乘估计有所改善,本文将根方估计作一拓广,得出了回归系数的广义根方估计~(K),其中K为对角阵,文中证明了广义根方估计~(K)较~(k)能更有效地改善最小二乘估计,并给出了广义根方估计的显式解,在此基础上,提出了广义根方估计的显式解和一种确定k_i的方法。     

误差分布未知下时空模型的自适应非参数估计

极大似然估计作为参数估计中较为有效的一种估计方法,在误差分布未知下无法进行,另一方面,时空数据经常含有奇异点或来自重尾分布,此时基于最小二乘的估计方法效果欠佳.考虑时空异质性和相关性,针对误差分布未知的时空模型,本文提出基于核密度估计的自适应非参数估计方法.在较弱的条件下证明了该估计量和已知误差分布下的局部极大似然估计...     

A Nonparametric Procedure to Detect Jumps in Regression Surfaces

This article proposes a local smoothing procedure for detecting jump location curves of regression surfaces. This procedure simplifies the computation of some existing jump detectors in the statistical literature. It also generalizes the Sobel edge detector in the image processing literature such that more observations can be used to smooth away random noise in the data. The problem to evaluate the performance of jump detectors is discussed and a new measurement of jump detection performance is suggested.     

A Test for Additivity in Nonparametric Regression

A simple consistent test of additivity in a multiple nonparametric regression model is proposed, where data are observed on a lattice. The new test is based on an estimator of the L ²-distance between the (unknown) nonparametric regression function and its best approximation by an additive nonparametric regression model. The corresponding test-statistic is the difference of a classical ANOVA style statistic in a two-way layout with one observation per cell and a variance estimator in a homoscedastic nonparametric regression model. Under the null hypothesis of additivity asymptotic normality is established with a limiting variance which involves only the variance of the error of measurements. The results are extended to models with an approximate lattice structure, a heteroscedastic error structure and the finite sample behaviour of the proposed procedure is investigated by means of a simulation study.     

On Confidence Intervals in Nonparametric Binary Regression via Edgeworth Expansions

Local confidence intervals for regression function with binary response variable are constructed. These intervals are based on both theoretical and “plug-in” normal asymptotic distribution of a usual statistic. In the plug-in approach, two ways of estimating bias are proposed; for them we obtain the mean squared error and deduce an expression of an optimal bandwidth. The rate of convergence of theoretical distributions to their limits is obtained by means of Edgeworth expansions. Likewise, these expansions allow us to deduce properties about the coverage probability of the confidence intervals. Theoretic approximations to that probability are compared in a simulation study with the corresponding coverage rates.     

截尾数据非参数回归函数加权核估计

在截尾数据下研究非参数回归函数加权核估计的相合性,对强相合性给出一些较弱的充分条件,这些结论较大程度地改进了现有的结论．     

误差为鞅差序列的非参数回归模型的完全相合性

在误差为鞅差序列的条件下,利用截尾方法及鞅差序列的指数不等式,研究了非参数回归模型P-C估计量的完全收敛性,且得到了完全收敛的收敛速度.     

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??For \rho-mixing samples, we discuss thestrong consistency of the nonparametric kernel regression estimator proposed by Gasser and Muller. Under more weaker conditions, its strong consistency and uniformly strong consistency are proved.     

Asymptotic Properties of Nonparametric Kernel Regression Estimator for \rho-Mixing Samples

For \rho-mixing samples, we discuss thestrong consistency of the nonparametric kernel regression estimator proposed by Gasser and Muller. Under more weaker conditions, its strong consistency and uniformly strong consistency are proved.     

Estimation and Bootstrap with Censored Data in Fixed Design Nonparametric Regression

We study Beran's extension of the Kaplan-Meier estimator for thesituation of right censored observations at fixed covariate values. Thisestimator for the conditional distribution function at a given value of thecovariate involves smoothing with Gasser-Müller weights. We establishan almost sure asymptotic representation which provides a key tool forobtaining central limit results. To avoid complicated estimation ofasymptotic bias and variance parameters, we propose a resampling methodwhich takes the covariate information into account. An asymptoticrepresentation for the bootstrapped estimator is proved and the strongconsistency of the bootstrap approximation to the conditional distributionfunction is obtained.     

NA样本非参数回归权函数估计的强相合性

在 NA样本下 ,讨论了非参数回归模型中权函数估计的强相合性及强一致相合性 ,并把这个结果应用于 Gasser- Muller估计和 Priestley and Chao估计 .     

随机右删失非参数回归模型的影响分析

将随机删失非参数固定设计回归模型转化为非参数回归模型进行研究;然后对此模型作了局部影响分析,得到计算影响矩阵及最大影响曲率方向的简洁公式;最后通过实例分析,验证了分析方法的有效性.     

Asymptotic Properties of a Nonparametric Regression Function Estimator with Randomly Truncated Data

In this paper, we define a new kernel estimator of the regression function under a left truncation model. We establish the pointwise and uniform strong consistency over a compact set and give a rate of convergence of the estimate. The pointwise asymptotic normality of the estimate is also given. Some simulations are given to show the asymptotic behavior of the estimate in different cases. The distribution function and the covariable’s density are also estimated.     

相依样本下非参数回归函数递推型核估计的渐近分布

设（Ｘｉ，Ｙｉ）１≤ｉ≤ｎ为来自二元总体（Ｘ，Ｙ）的平稳，φ－混合样本，记ｍ（ｘ）△Ｅ（Ｙ│Ｘ＝ｘ），ｍ（ｘ）的一种递推型核估计为ｍｎ（ｘ）＝ｎ∑ｉ＝１ｈｉ＾－１Ｙｉｋ（（ｘ－Ｘｉ）／ｈｉ）／ｎ∑ｊ＝１ｈ＾－１ｊｋ（ｘ－Ｘｊ）／ｈｊ）。本文在一定的条件下证明了（ｎ／（ｎ∑ｊ＝１ｈ＾－１ｊ）＾１／２）（ｍｎ（ｘ１）－ｍ（ｘ１），ｍｎ（ｘ２）－ｍ（ｘ２），．．．ｍｎ（ｘｒ０）－ｍ（ｘｒ０））′依分布收     

基于协变量缺失的Horvitz-Thompson加权分位回归估计方法

含有协变量缺失的数据缺失问题是现代统计分析中的热点之一.当缺失数据中同时存在厚尾,偏斜和异方差问题时则更加难以处理.为此,本文提出一种逆概率加权分位回归估计来研究响应和协变量之间的关系.与经典估计方法相比具有明显优势,一方面,该估计量使用了所有可用的数据,并且允许缺失的协变量与响应高度相关;另一方面,该估计量在所有分位数水平上满足一致性和渐近正态性.通过模拟验证了该方法的在有限样本下的有效性,进一步将该方法推广到线性多元回归模型和非参数回归模型.