删失回归模型的随机加权逼近

Raoand Zhao(1992)提出了一种用随机加权的方法去逼近线性回归模型中M-估计的渐近分布。之前，Fang and zhao(2002)把这种方法推广到设计阵是随机的删失回归模型．本文，我们把这个结果推广到设计阵是非随机的删失回归模型，并证明该随机加权方法的一些大样本性质。     

删失指标随机缺失下一类非参数函数的加权局部多项式估计及其应用

本文在右删失数据中删失指标部分随机缺失下,构造了一类非参数函数的校准加权局部多项式估计以及插值加权局部多项式估计,并建立了这些估计的渐近正态性;作为该方法的应用,导出了条件分布函数、条件密度函数以及条件分位数的加权局部线性双核估计和插值加权局部线性双核估计,并且得到了这些估计的渐近正态性;最后,在有限样本下对这些估计进行了模拟.     

删失数据下线性回归模型的参数估计

主要叙述在数据观测不完全的情况下,采用最小二乘法对线性回归模型回归系数的估计及估计量的渐进性质,并给出数据模拟．     

删失指标随机缺失下条件分位数的加权核估计

在右删失数据下,当删失指标随机缺失时,对条件分布函数分别构造了校准加权核估计,插值加权核估计以及逆概率加权核估计;然后由这些估计分别导出了条件分位数的核估计,并建立了这些估计的渐近正态性;最后,在有限样本下,对这些估计进行了数值模拟,分析了各估计的优缺点.     

右删失数据下生存函数的随机加权估计

本文利用随机加权思想提出了右删失数据下生存函数的随机加权估计,证明了所给的随机加权估计的强相合性.     

随机删失下概率密度核估计的光滑Bootstrap逼近

本文研究随机删失概率密度估计的光ｂｏｏｔｓｔｒａｐ逼近。给出了光滑ｂｏｏｔｓｔｒａｐ逼近成立的充分条件，并证明了概率密度的光滑ｂｏｏｔｓｔｒａｐ估计方差几乎处处收敛到概率密度核估计的渐近方差。     

随机删失非参数回归模型的离差度量

主要研究了随机删失非参数固定设计回归模型的离差度量.首先利用随机删失非参数回归模型的性质和生存分布的Kaplan-Meier乘积限估计,将原模型转化为非参数回归模型进行研究;然后对模型作了离差度量分析,得到了模型的离差度量序列;最后通过实例分析,验证了上述诊断方法的有效性.     

随机删失数据非线性回归模型的最小一乘估计

研究了随机删失数据非线性回归模型的最小一乘(LAD)估计问题, 证明了LAD估计量的渐近性质, 包括相合性、依概率有界性和渐近正态性等. 模拟结果显示对删失数据回归问题, LAD估计仍比最小二乘估计(LSE)稳健.     

左截断右删失数据下百分剩余寿命函数的非参数估计

在左截断右删失数据的模型中，文章讨论３了可靠性中一类重要的α－百分剩余寿命函数的非参数估计，证明了该估计的强一致相合性并获得了该仗垢弱收敛性结果。     

随机删失下回归函数最近邻估计的强收敛速度

针对随机右删失数据, 就截尾时间变量的分布已知和未知两种情况, 构造了一类非参数回归函数的最近邻估计, 在适当的条件下得到估计量的强收敛速度.     

基于带有缺失协变量的分位数回归模型的分布式优化方法研究

文章以大数据为背景, 基于带有随机缺失协变量的分位数回归模型, 采用分布式存储的思想, 将数据随机存储在不同的机器中.通过构造全局损失函数的交互有效替代损失函数, 将全局优化问题转变为局部优化问题.设计了Proximal ADMM算法对估计量进行迭代求解, 寻找最优值.文章解决了带有缺失协变量的分位数回归模型中的数据存储困难和机器之间交互复杂度高的问题.理论研究表明:在一定的正则条件下, 提出的分布式估计量具有相合性和渐近正态性.数值分析表明:在有限次主从机器之间交互次数下, 提出的分布式优化方法得到的估计误差递减并趋于全局最优Oracle方法得到的估计误差, 且比基于平均的OneShot方法和加权最小二乘回归的估计误差更小.     

Polynomial Regression with Censored Data based on Preliminary Nonparametric Estimation

Consider the polynomial regression model , where σ²(X)=Var(Y|X) is unknown, and ε is independent of X and has zero mean. Suppose that Y is subject to random right censoring. A new estimation procedure for the parameters β₀,...,β _p is proposed, which extends the classical least squares procedure to censored data. The proposed method is inspired by the method of Buckley and James (1979, Biometrika, 66, 429–436), but is, unlike the latter method, a noniterative procedure due to nonparametric preliminary estimation of the conditional regression function. The asymptotic normality of the estimators is established. Simulations are carried out for both methods and they show that the proposed estimators have usually smaller variance and smaller mean squared error than the Buckley–James estimators. The two estimation procedures are also applied to a medical and an astronomical data set.     

Empilrical likelihood for non-parametric regression models with missing responses: Multiple design case

Empirical likelihood(EL) ratio statistic on θ = g(x) is constructed based on the inverse probability weighted imputation approach in a nonparametric regression model Y = g(x) + ε(x ∈ [0,1]p) with fixed designs and missing responses,which asymptotically has χ12 distribution.This result is used to obtain a EL based confidence interval on θ.     

Regression analysis of right-censored failure time data with missing censoring indicators

This paper discusses regression analysis of right-censored failure time data when censoring indicators are missing for some subjects. Several methods have been developed for the analysis under different situations and especially, Goetghebeur and Ryan considered the situation where both the failure time and the censoring time follow the proportional hazards models marginally and developed an estimating equation approach. One limitation of their approach is that the two baseline hazard functions were assumed to be proportional to each other. We consider the same problem and present an efficient estimation procedure for regression parameters that does not require the proportionality assumption. An EM algorithm is developed and the method is evaluated by a simulation study, which indicates that the proposed methodology performs well for practical situations. An illustrative example is provided.     

Non-parametric vs parametric forecasting in time series: A computational point of view

The finite sample behaviour of non-parametric predictors is considered for time series. Among other results, it is shown by simulation arguments that such predictors compare favourably with predictors based on parametric models in the spirit of the usual Box-Jenkins approach.     

Weighted L quantile distance estimators for randomly censored data

The asymptotic properties of a family of minimum quantile distance estimators for randomly censored data sets are considered. These procedures produce an estimator of the parameter vector that minimizes a weighted L² distance measure between the Kaplan-Meier quantile function and an assumed parametric family of quantile functions. Regularity conditions are provided which insure that these estimators are consistent and asymptotically normal. An optimal weight function is derived for single parameter families, which, for location/scale families, results in censored sample analogs of estimators such as those suggested by Parzen.     

Bootstrapping the nonparametric ARCH regression model

In this paper we introduce the nonparametric AR(1)–ARCH(1) model and show weak consistency of the Nadaraya–Watson estimators for the model. We propose a residual and a wild bootstrap method and prove weak consistency of the bootstrap estimators.