随机右截断情形下连续过程生存函数的估计及其性质

截断数据是生存分析的重要研究内容，而以往关于截断数据的讨论仅限于离散场合．本文将截断数据的问题推广到连续场合，对右截断下连续过程的生存函数的估计进行了讨论，并进一步证明了估计量的强相合性．     

二阶抽样总体比率的估计

本文研究二阶抽样下总体比率的估计问题, 就若干种情形给出总体比率的几种可行的估计量,讨论了它们的统计性质.     

初始值外生给定下动态空间面板数据模型的拟极大似然估计

基于初始值外生性假定,本文构建的动态空间面板数据固定效应模型内含空间自相关和空间误差两种结构,并采用拟极大似然方法推导模型参数具有渐近性质和渐近分布的估计量;进一步,蒙特卡洛模拟实验结果显示,本文所推导的拟极大似然估计量呈现的统计特征与理论结论一致,即具有随样本容量的增加而不断改进的渐近性质;分别讨论模型中存在的时间和空间两类维度的变化影响发现,参数估计量的渐近表现对时间维度的变化较为敏感,在空间维度难以增加情形下,时间维度的有效增加能够有效地提高参数估计量性质。     

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。     

扩散模型中扩散系数的非参数组合估计

为了提高扩散系数估计的准确度, 我们利用动态组合时间域与状态域信息提出一个新的组合估计量. 我们发现所提组合估计量能有效估计扩散模型的扩散系数, 正如在本文中模拟所示. 在一定的条件下, 建立了估计量的渐进正态性, 并证明了时间域估计量与状态域估计量是渐进独立的. 大量的模拟展示了所提组合估计量优于单域估计量, 也优于本文所提估计量.     

人口总数估计:基于三系统估计量与比率估计量的组合方法

受多种因素影响,人口普查结果不可避免地偏离真实人口总数,如何构造一个统计性质优良,适用范围广的人口总数估计量,精准把握人口变动趋势是政府统计工作的重要议题.本文解读了英国统计局普查年人口总数估计的经验方法,据此提出三系统估计量与比率估计量组合的人口总数估计方法.模拟研究结果表明,在人口总体合理分层的基础上,新方法能较好...     

裂区设计连续调查的条件影响及重抽样核实调整

条件的影响是有匹配样本的连续调查特有的计量误差来源。本文在变异计量误差模型之下，研究了未调整时条件影响对两期裂区设计连续调查中采用的组合差估计量的统计影响，同时提出了重抽样核实调查方法，得到了调整后的无偏估计量，计算了调整后估计量的方差。讨论了调整后估计量准确度比未调整估计量准确度高的条件。     

裂区设计连续调查的条件影响及重抽样核实调整

条件的影响是有匹配样本的连续调查特有的计量误差来源。本文在变异计量误差模型之下，研究了未调整时条件影响对两期裂区设计连续调查中采用的组合差估计量的统计影响，同时提出了得抽样核实调整方法，得到了调整后的无偏估计量，计算了调整后估计量的方差，讨论了调整后 估计量准确度比未调整估计量准确度高的条件。     

单参数指数分布参数比率统计推断的研究

本文在产品寿命服从单参数指数分布的无替换定数截尾寿命试验场合下,提出两独立产品的平均寿命比率的两个估计量并研究了它们的均值、方差、方差的估计、大截尾数性质、置信区间及最优截尾数的确定问题.然后进行了数据模拟,进一步验证了所提估计量的有效性.     

利用加权对称估计量对季节性时间序列的单位根检验

本文提出对季节性时间序列利用加权对称估计量的单位根检验,导出相应统计量的极限分布。用MonteCarlo方法计算经验百分位数及检验势,并对最小平方估计量,简单对称估计量和加权对称估计量的经验检验势作了比较。     

Evaluations of Parameters for the Optimization of S.S.O.R. and A.D.I. Preconditioning

The main goal of this paper is to give two ways to estimate the needed parameters in order to obtain the condition number of S.S.O.R. preconditioned matrices, namely, the algebraic matricial formulation of convexity Riesz theorem and the tridiagonal Fourier analysis. The improvement with respect to Axelsson's approach is explicitly given. Estimations of the condition number in the case of A.D.I. preconditioning is also considered.     

Optimization of the Relaxation Parameter for S.S.O.R. and A.D.I. Preconditioning

We present and compare several approaches for the optimization of the relaxation parameter both for A.D.I. and S.S.O.R. basic iteration and preconditioning conjugate gradient method. For each kind of preconditioning a detailed link between estimates of the spectral radius of the iteration matrix and of the condition number resulting from preconditioning is proposed. It allows to choose the best approach in order to obtain the optimal relaxation parameter and the corresponding optimal estimates either of the spectral radius of the iteration matrix and of the resulting condition mumber of the S.S.O.R. and A.D.I. preconditioning.     

There is No Low Maximal D.C.E. Degree

We show that for any computably enumerable (c.e.) set A and any set L, if L is low and , then there is a c.e. splitting such that . In Particular, if L is low and n‐c.e., then is n‐c.e. and hence there is no low maximal n‐c.e. degree.     

D.c. sets,d.c. functions and nonlinear equations

Ad.c. set is a set which is the difference of two convex sets. We show that any set can be viewed as the image of a d.c. set under an appropriate linear mapping. Using this universality we can convert any problem of finding an element of a given compact set in ⁿ into one of finding an element of a d.c. set. On the basis of this approach a method is developed for solving a system of nonlinear equations—inequations. Unlike Newton-type methods, our method does not require either convexity, differentiability assumptions or an initial approximate solution.The revision of this paper was produced during the author's stay supported by a Sophia lecturing-research grant at Sophia University (Tokyo, Japan).     

S.A.G.B.I. bases for rings of formal modular seminvariants

We use the theory of S.A.G.B.I. bases to construct a generating set for the ring of invariants for the four and five dimensional indecomposable modular representations of a cyclic group of prime order. We observe that for the four dimensional representation the ring of invariants is generated in degrees less than or equal to 2p–3, and for the five dimensional representation the ring of invariants is generated in degrees less than or equal to 2p–2. Received: January 22, 1997     

On Weakly P.P. Rings

We introduce, in this paper, the right weakly p.p. rings as the generalization of right p.p. rings. It is shown that many properties of the right p.p. rings can be extended onto the right weakly p.p. rings. Relative examples are constructed. As applications, we also characterize the regular rings and the semisimple rings in terms of the right weakly p.p. rings.     

Projective normality of G.I.T. quotient varieties modulo finite groups

We prove that for any finite dimensional representation V of a finite group G of order n the quotient variety G??(V) is projectively normal with respect to descent of 𝒪(1)^?l where l = lcm{1,2,3,4,…,n}. We also prove that for the tautological representation V of the alternating group A_n the projective variety A_n??(V) is projectively normal with respect to the descent of the above line bundle.     

I.I.D.随机变量序列矩完全收敛的精确渐近性

{X,Xn;n≥1}为独立同分布的随机变量序列, EX=0,01 p/2满足E|X|r<∞,且E|X|3<∞,那么其中Z服从均值为0,方差为σ2的正态分布.     

There is no low maximal d. c. e. degree – Corrigendum

We give a corrected proof of an extension of the Robinson Splitting Theorem for the d. c. e. degrees. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Complete moment convergence for i.i.d. random variables

In the paper, the complete moment convergence is obtained for i.i.d. random variables such that all moments exist, but the moment generating function does not exist. The main results extend the related known works due to Gut and Stadtmüller.