Hazard Rate Regression Using Ordinary Nonparametric Regression Smoothers

Abstract

This article proposes a method for nonparametric estimation of hazard rates as a function of time and possibly multiple covariates. The method is based on dividing the time axis into intervals, and calculating number of event and follow-up time contributions from the different intervals. The number of event and follow-up time data are then separately smoothed on time and the covariates, and the hazard rate estimators obtained by taking the ratio. Pointwise consistency and asymptotic normality are shown for the hazard rate estimators for a certain class of smoothers, which includes some standard approaches to locally weighted regression and kernel regression. It is shown through simulation that a variance estimator based on this asymptotic distribution is reasonably reliable in practice. The problem of how to select the smoothing parameter is considered, but a satisfactory resolution to this problem has not been identified. The method is illustrated using data from several breast cancer clinical trials.     

Hazard Rate Estimation in Nonparametric Regression with Censored Data

Consider a regression model in which the responses are subject to random right censoring. In this model, Beran studied the nonparametric estimation of the conditional cumulative hazard function and the corresponding cumulative distribution function. The main idea is to use smoothing in the covariates. Here we study asymptotic properties of the corresponding hazard function estimator obtained by convolution smoothing of Beran's cumulative hazard estimator. We establish asymptotic expressions for the bias and the variance of the estimator, which together with an asymptotic representation lead to a weak convergence result. Also, the uniform strong consistency of the estimator is obtained.     

Nonparametric Estimation for Semi-Markov Processes Based on its Hazard Rate Functions

The problem of estimating the Markov renewal matrix and the semi-Markov transition matrix based on a history of a finite semi-Markov process censored at time T (fixed) is addressed for the first time. Their asymptotic properties are studied. We begin by the definition of the transition rate of this process and propose a maximum likelihood estimator for the hazard rate functions and then we show that this estimator is uniformly strongly consistent and converges weakly to a normal random variable. We construct a new estimator for an absolute continous semi-Markov kernel and give detailed derivation of uniform strong consistency and weak convergence of this estimator as the censored time tends to infinity. This revised version was published online in June 2006 with corrections to the Cover Date.     

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.     

双边删失场合生存函数的非参数Bayes估计的弱收敛性

本文针对双边删失数据讨论了生存函数的非参数Bayes估计问题,运用Fred-holm积分的一些经典结果,文中证明了该估计弱收敛的一个Gaussian过程。     

中国银行间拆借利率扩散模型的极大拟似然估计

本文用极大拟似然估计法估计了中国银行间市场七天拆借利率扩散模型的参数。并用自助法对众多不同的模型进行了广义拟似然比检验。结论表明:中国货币市场利率具有均值回复效应:利率敏感系数γ值为1.421265,对利率水平具有较高敏感性。     

NA样本下回归函数导数估计的收敛速度

本文对NA样本,在一定条件下,研究了非参数回归函数导数核估计逐点强相合及一致强相合的收敛速度.     

纵向数据下非参数带测量误差的部分线性变系数模型的估计

本文研究纵向数据下非参数部分带有测量误差的部分线性变系数模型的估计.利用B样条函数近似模型中的变系数函数,构造偏差修正的二次推断函数,得到模型中未知参数和变系数函数的估计.证明变系数函数估计量的相合性和参数估计量的渐近正态性.数值模拟和实例分析结果表明所提估计方法在有限样本下的有效性.     

Modified estimators for the change point in hazard function

We propose the consistent estimators for the change point in hazard function by improving the estimators in [A.P. Basu, J.K. Ghosh, S.N. Joshi, On estimating change point in a failure rate, in: S.S. Gupta, J.O. Berger (Eds.), Statistical Decision Theory and Related Topics IV, vol. 2, Springer-Verlag, 1988, pp. 239–252] and [H.T. Nguyen, G.S. Rogers, E.A. Walker, Estimation in change point hazard rate model, Biometrika 71 (1984) 299–304]. By a simulation study, we show that the proposed estimators are more efficient than the original estimators in many cases.     

失效率的综合E-Bayes估计

该文提出了可靠性参数的一种新估计方法综合E-Bayes估计法.在无失效数据情形下给出了失效率的E-Bayes估计的定义,并给出了失效率的E-Bayes估计。在引进失效信息后，给出了失效率的E-Bayes估计，并在此基础上给出了失效率和其它参数的综合E-Bayes估计。最后，结合实际问题进行计算，结果表明该文提出的方法可行且便于应用。     

下一个失效时刻的非参数估计

本文研究下一个失效时刻的非参数估计问题.文中所给出的估计量在一定条件下a.s.收敛,同时也讨论了估计量的渐近正态性.     

右删失长度偏差数据分位数差的非参数估计

利用长度偏差数据所特有的辅助信息,对带右删失的长度偏差数据的分位数差提出了一种新的非参数估计.该方法提高了估计的有效性,所得的估计量形式简洁,便于计算.同时,本文用经验过程理论建立了该分位数差估计的相合性及渐近正态性,并给出方差估计的重抽样方法.本文还通过数值模拟考察了该估计量在有限样本下的表现,并将其应用到一个关于老年痴呆的实际数据中.     

无失效数据情形失效率的估计及其应用

该文对指数分布的无失效数据,在失效率　的先验密度的核为　ａ－１时,给出了失效率　的Ｂａｙｅｓ估计和多层Ｂａｙｅｓ估计．并对某液压电动机,在寿命眼从指数分布时,给出了该液压电动机无失效数据情形可靠度的估计．     

利用区间删失数据的分布函数估计及其收敛速度

讨论任意m点均匀分布(m≥3)的情况,用m点均匀分布的累积分布函数去逼近连续总体的分布函数,在适当的条件下,证明了用区间删失数据估计分布函数具有收敛速度D(n)-2/9.     

Nonparametric Estimation of the Measurement Error Model Using Multiple Indicators

This paper considers the nonparametric estimation of the densities of the latent variable and the error term in the standard measurement error model when two or more measurements are available. Using an identification result due to Kotlarski we propose a two-step nonparametric procedure for estimating both densities based on their empirical characteristic functions. We distinguish four cases according to whether the underlying characteristic functions are ordinary smooth or supersmooth. Using the loglog Law and von Mises differentials we show that our nonparametric density estimators are uniformly convergent. We also characterize the rate of uniform convergence in each of the four cases.     

区间截断情况下, 分布函数估计及其收敛速度

首先将文[11]的结论推广到任意$k$点均匀分布(k≥3), 然后用k点均匀分布的累积分布函数去逼近连续总体的分布函数, 在适当的条件下, 证明了用区间数据估计出的分布函数收敛速度为O(n)^{^-2/9}.     

无失效数据情形失效率的综合E-Bayes估计

给出了无失效数据情形失效率的E-Bayes估计和引进失效信息后的E-Bayes估计,并在此基础上给出了失效率和可靠度的综合E-Bayes估计。最后,结合实际问题进行了计算,对估计结果进行了分析,并将它们与未假定先验信息时的非Bayes置信限进行比较,结果表明该方法是合理的。     

N-A样本下单边截断型分布族位置参数函数E·B估计的收敛速度

§ 1.　IntroductionandtheMainResult　　Asfarasweknown ,theissuesofEmpirialBayes(E·B)statisticsmainlyincludedE·Bes timationsandE·Btests ,whichwereconsideredandstudiedformerlyunderi.i.d .samples.However,insteadofgetingi.i.d .samplesinsomefieldssuchasreliabletheory ,penetratedtheoryandsomemultivariateanalysis,etc .,weoftengetsomeassociatedsamplessuchasposi tivelyassociationandnegativelyassociation .Recently ,professorWEI [3],XU [4],andLING [5 ]consideredrespectivelytheissuesofE·Btesta…     

非参数回归函数核估计的Lp收敛速度

在p≥1和适当的条件下，给出了回归函数m(x)＝E（Y|X＝x）的核估计的若干种Lp收敛速度，改进并推广了韦来生（1984）的结果。     

Functional inference in semiparametric models using the piggyback bootstrap

This paper introduces the “piggyback bootstrap.” Like the weighted bootstrap, this bootstrap procedure can be used to generate random draws that approximate the joint sampling distribution of the parametric and nonparametric maximum likelihood estimators in various semiparametric models, but the dimension of the maximization problem for each bootstrapped likelihood is smaller. This reduction results in significant computational savings in comparison to the weighted bootstrap. The procedure can be stated quite simply. First obtain a valid random draw for the parametric component of the model. Then take the draw for the nonparametric component to be the maximizer of the weighted bootstrap likelihood with the parametric component fixed at the parametric draw. We prove the procedure is valid for a class of semiparametric models that includes frailty regression models airsing in survival analysis and biased sampling models that have application to vaccine efficacy trials. Bootstrap confidence sets from the piggyback, and weighted bootstraps are compared for biased sampling data from simulated vaccine efficacy trials.