查询词典 estimator

And then some ellipses that AUGR estimator is better than the OLS estimator and AUGL estimator is better than the OLS estimator are given, respectively.Second, the definition of the almost unbiased unified biased estimator is proposed. This definition includes the familiar almost unbiased estimators in literatures, and it is the unified expression of the familiar almost unbiased estimators. Followed the biased and variance are compared of AUUB estimator and the unified biased estimator, respectively. AUUB estimator has smaller bias than UB estimator and the variance of AUUB estimator is between the variance of UB estimator and 4 times of the variance of UB estimator. Finally the properties of AUUB estimator are discussed. The conclusion is gained that there are parameters made AUUB estimator is better than OLS estimator in terms of their mean square error. The sufficient and necessary condition that AUUB estimator is admissible is given. The ellipse is given that AUUB estimator is

然后给出了几乎无偏统一有偏估计的定义，该定义包括了文献中常见的几乎无偏估计，实现了常见几乎无偏估计的统一表达式；接下来我们比较了几乎无偏统一有偏估计与统一有偏估计的偏度与方差，得出了几乎无偏统一有偏估计比统一有偏估计有较小的偏度，几乎无偏统一有偏估计的方差介于统一有偏估计的方差与统一有偏估计的方差的四倍之间的结论；最后我们对统一有偏估计的主要性质作了讨论，证明了存在参数K，S使得几乎无偏统一有偏估计在均方误差意义下优于最小二乘估计的结论，给出了几乎无偏统一有偏估计为可容许估计的充要条件，还给出了在均方误差阵意义下几乎无偏统一有偏估计优于最小二乘估计的椭球。

We first state general linear model, ridge-type estimator and general ridge-type estimator, and the constraint biased estimator. And then, we introduce some basic theory about matrix and some conclusion about the admissibility of estimator in Gauss-Markov model. In the third chapter, we discussion several equivalent characterization of the best linear unbiased estimation, we proved that admissible characterization of admissible of linear estimation is as conditional general ridge-type estimation in general linear model. A necessary and sufficient condition that homogeneous linear estimator is admissible estimator is obtained.

本文首先概述了一般线性模型，岭估计及约束岭估计的发展历史和研究现状，在第二章介绍了矩阵的一些基本知识和可容许性的一些基本结论，第三章讨论了一般线性模型最佳线性无偏估计的几个等价条件，以及线性估计的可容许性特征，得到了一般线性模型的可容许线性估计均具有条件广义岭估计的形式，给出了一个齐次线性估计为可容许估计的充分必要条件。

Though the almost unbiased estimator was still a biased estimator, it has smaller bias than corresponding biased estimator.In this paper, we first study the properties of the almost unbiased generalized ridge estimator and the almost unbiased generalized Liu estimator.

但有偏估计毕竟偏离参数的真值，因此学者们又提出了几乎无偏估计的概念，虽然几乎无偏估计仍然是有偏估计，但是它比相应的有偏估计有更小的偏度。

Four new relative efficiencies of the best linear unbiased estimator to the covariance improvement estimator for the unknown parameter vector are given, and three new relative efficiencies of the least square estimator to the covariance improvement estimator for the unknow parameter vector are given.

本文考虑相依模型，对其未知参数向量给出了其最佳线性无偏估计相对于协方差改进估计的四种相对效率，同时，还给出了最小二乘估计相对于协方差改进估计的三种相对效率，在不同条件下，分别给出了相对效率的上界与下界。

As to seemingly unrelated regression system,a new biased contracting estimator of the parameters is put forward,which is the combination of generalized ridge covariance-improved estimator and Stein estimator,and the good features of this estimator in mean square error is discussed.

对于一类相依回归系统，结合广义岭型协方差改进估计与Ste in估计，提出了一种新的有偏压缩估计，，并讨论了该估计在均方误差下的优良性质

In this paper we discuss the influence problem of Ridge Estimator in general linear regression model, study the influence analysis on Ridge Estimator with covariance matrix disturbance and data deletion, define Cook distance of Rideg Estimator based on biased estimator.

讨论一般线性回归模型岭估计的影响+分析问题，研究了协方差阵扰动和数据删除对岭估计的影响，给出了岭估计基于有偏估计的Cook距离。

To overcome this problem, many authors proposed some biased estimators to alternate the least squared estimator. In some sense, these estimators improved the least squared estimator.However, the biased estimator was apart from the true value of parameter, so some statisticians proposed the notation of the almost unbiased estimator.

人们发现设计阵的"病态"是导致Stein现象的根源，为了克服共线性性，人们在文献中相继提出了许多有偏估计来替代最小二乘估计，这些估计从某种意义上讲，都改进了最小二乘估计。

The convergence of them is proved, i.e if the parameters estimation is consistent, then self-tuning fusion estimator will converge to the optimal fusion estimator with known model parameters and noise statistics, and the accuracy of self-tuning fusion estimator is higher than that of each local self-tuning estimator.

证明了它们的收敛性，即若ARMA新息模型的参数估计是一致的，则自校正信息融合Wiener估值器将收敛于当模型参数和噪声方差己知时的最优信息融合Wiener估值器，且自校正信息融合Wiener估值器的精度高于每个局部自校正Wiener估值器。

In the fourth chapter, we discussion the characterization of admissible in the general linear model under equality constraint and inequality constraint, we give the necessary and sufficient condition that homogeneous linear estimator is admissible estimator, and by using the relationship between homogeneous and inhomogeneous linear estimator, we obtain the characterization of admissible inhomogeneous linear estimator.

第四章分别在带等式约束条件以及不等式约束条件下，讨论了一般线性模型线性估计的可容许性特征，给出了在约束条件下齐次线性估计为可容许估计的充分必要条件，同时利用齐次线性估计与非齐次线性估计之间的关系，把齐次线性估计的可容许性特征推广到了非齐次线性估计的可容许性特征。

The alternative estimators used in this paper include least squares estimator, stratified weighted least squares estimator, probability weighted least squares estimator, and Quasi-Aitken weighted least squares estimator.

中文摘要抽样调查设计随著资讯需求的增加日益复杂，然若参数的估计方法无法配合所使用的抽样调查设计，则统计推论结果将难以达到预期的精确度。

Although translator has turned from being a crystal ball by which the original culture can unrestrainedly penetrate to another crystal ball by which the target culture can freely traverse, the translator's personal embodiment, in the process of cognitive act, are still absent in translation studies. Translators are still subjects without body or simply disembodied subjects.

译者虽然由原语文化可以自由穿透的玻璃球变成了译语文化可以自由穿越的玻璃球，但译者认知过程中的个体体验在翻译研究中依然缺席，译者依然仅仅是一个没有躯体体验的主体。

Chillingly, he claimed our technology is 'not nearly as sophisticated' as theirs and "had they been hostile", he warned 'we would be been gone by now'.

令人毛骨悚然的，他声称我们的技术是'并不那么复杂，像他们一样，和"如果他们敌意"，他警告说，'我们将现在已经过去了。