方差比

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。

Especially, the combined ratio estimator of domain total is investigated under stratified complemental sampling when auxiliary information can be used.

及该方案在分层抽样下的推广，在有辅助信息可用时构造域总量的分层联合比估计，并给出其方差和方差估计公式，同时我们给出了模拟结果，从模拟结果可以看出，给出的方差估计是估计量方差的近似无偏估计。

In this case, the received carrier is modulated by unknown Doppler frequency and frequency rate. The estimation techniques as maximum likelihood estimator and extended Kalman filter are described and compared in our dissertation by tracking a common simulated highdynamic trajectory.

文中详细推导了任意信噪比情况下，时延和多普勒频率估计的方差下限表达式：在信噪比高于门限信噪比的情况下，具体推导了估计方差的Cramer-Rao限；在信噪比低于门限信噪比时，估计的方差下限还与失锁概率有关。

For the problem that the suppression of co-channel interference and suppression of noise can't be balanced in signal-to-jamming and noise ratio maximization method for the linear precoding of multiuser multiple-input multiple-output downlink systems, an improved scheme that the term of noise variance is modified as a piecewise linear function is proposed, in which the balance between suppression of co-channel interference and suppression of noise can still be maintained even when the noise variance is a small value through piecewise modifying the term of noise variance, and thus the bit error rate and capacity of the systems are further improved.

针对多用户多输入多输出系统下行链路线性预编码的信干噪比最大化方法中，共信道干扰抑制和噪声抑制不能有效平衡的问题，提出将其中的噪声方差项修正为以噪声方差为变量的分段线性函数的改进方案。该方案通过对噪声方差项的分段修正，在噪声方差的值较小时依然能够保持共信道干扰抑制和噪声抑制间的平衡，从而使系统的误比特率性能和容量得到进一步提高。

R2 The adjusted R2 is 1 minus the ratio of sample variance of the OLS residuals (after correcting the degrees of freedom) to the sample variance of y.

调整过的R2是1减去OLS残差的样本方差与y的样本方差之比。

Based on Wilcoxon rank sum test, variance ratio test and Fama-MacBeth regression method, this study finds that Chinese listed companies tend to issue new equity after information disclosure. The two regular corporate financial reports around its issuing announcement are all informative, but the one before the issuing announcement does not transfer better information to the market.

基于Wilcoxon秩和检验、方差比检验以及Fama-MacBeth回归方法的实证结果表明：我国上市公司倾向于在信息披露之后公告新股发行；我国上市公司发行公告前后两个定期报告皆具有信息含量，但发行公告之前的定期报告没有向市场传递更好的信息。

We can found that China stock market is not completely weak effective by auto-correlation test, runs test, unit root test and variance ratio test. The TT-kyle model is derived from kyle model by adding weak effectiveness and irrational factor. This chapter describes impact of weak effectiveness and irrational factor on the trading volume and price. The fifth part analyses the relationship between the transaction duration and insider trading.

第四部分研究了市场有效性与内幕交易的关系，运用自相关性检验、游程检验、单位根检验、方差比检验等方法对我国证券市场的弱有效性进行验证，得出我国证券市场不完全弱有效的结论，在Kyle模型中加入弱有效性和非理性因素，提出了TT-kyle模型，分析弱有效性和非理性因素对内幕交易者的交易量和价格的影响，并提出了提高我国证券市场效率的相关对策建议。

With the methods of unit root and variance ratio ,the closing prices of nature rubber futures contract No.

以上海期货交易所天然橡胶7月合约的每日收盘价为研究对象，采用的方法是单位根检验和方差比检验相结合，通过检验期货价格序列是否服从随机步游过程，来判断市场是否具有弱式有效性。

Then, separately through the variance ratio method and the cointegeration approach, tests the efficiency and the unbiasbility of price discovery function, thereby identifies the realization degree of China's grain futures market price discovery function.

然后，分别用方差比检验法和协整关系检验法实证检验了我国粮食期货市场价格发现功能的有效性和无偏性，从而检验我国粮食期货市场价格发现功能的实现程度。

At first, setting up the arith relation between the signal input and the signal output of the generalized multi-carrier system of the Discrete Fourier Test spread-spectrum; then setting equilibria parameters of the frequency field equilibria subcarrier of the generalized multi-carrier system of the DFT spread-spectrum according to channel frequency response, channel noise variance and equilibria method; then calculating average power of useful signal, interferential average power between signals as well as noise variance of the generalized multi-carrier system receiving terminal of the DFT spread-spectrum according to the arith relation as well as the frequency field equilibria parameter, and recomputing available signal information noise ratio, so as to calculate the available signal information noise ratio of the generalized multi-carrier transmission system accurately, the method for estimating the available signal information noise ratio can be used for link self-adapting transmission solution of the generalized multi-carrier system based on Discrete Fourier Test spread-spectrum and radio material management.

一种DFT扩频的广义多载波系统的SINR估计方法，其通过首先建立所述离散傅立叶变换扩频的广义多载波传输系统的信号输入输出之间的数学关系，然后根据信道频率响应、信道噪声方差和均衡方法，设定所述DFT扩频的广义多载波传输系统的频域均衡子载波的均衡系数，再根据所述数学关系及所述频域均衡系数分别计算所述DFT扩频的广义多载波传输系统接收端有用信号的平均功率、信号间干扰的平均功率以及噪声方差，再计算有效信干噪比，如此以实现对广义多载波传输系统的有效信干噪比的准确计算，该有效信干噪比估计方法可用于基于离散傅立叶变换扩频的广义多载波传输系统的链路自适应传输方案和无线资源管理方面。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。