方差比

The main contributions in this area are summarized as follows,? The closed-form formula and its asymptotic form of system outageprobability are derived, through which it is shown that the outage probability decreased by a factor ofγ~(hereγdenotes the average SNR);? The closed-form formula of outage capacity is derived, through which weshow that 1 outage capacity increases with the increases of mean value of sytem SNR, and decreases with the increase of the variance of system average SNR; 2 in order to obtain higher outage capacity, the number of transmit antenna should be no more than that of receive antennas.?

特别的，针对多用户发送天线选择／最大比合并系统，主要贡献总结如下：·理论推导出中断概率的闭式解及其近似解，通过该近似解，可以得到中断概率以γ~的形式减少(这里γ是平均信噪比SNR)·推导出平均中断容量的闭式表达式，研究表明：1中断容量随着有效平均SNR的均值的增加而增加，随着有效平均SNR的方差的增大而减小；2为了获得更高的中断容量，发送天线的数目应当不大于接收天线的数目。

When the underlying error term for tobit model is known to be normally distributed and homoskedasticity, maximum likelihood estimation is consistent and asymptotically normally distributed.

半参数估计是一种参数和非参数估计的混合，比相应的参数模型更能一致的估计参数，而且比非参数模型估计更精确，其优点是无需假定误差项分布，所以它对非正态和异方差是稳健的。

To compare the image quality of the three sequences in two groups by One-Way ANOVA and T Test. The qualitative assessment standards include clarity, artifacts, signal uniformity, the conspicuity of enhanced vein and the observable grade of intrahepatic venous branchs. The quantitative assessment standards include SNR and CNR of intrahepatic portal vein and hepatic veins. Furthermore, the anatomy and variations of the intrahepatic portal vein and hepatic veins are statistical analysed.

通过方差分析和T检验分别对A、B组三个序列的图像质量进行比较，评定标准包括清晰度、伪影、信号均匀性、静脉强化程度及肝内静脉分支显示级数等定性指标和肝内门静脉、肝静脉的SNR(Signal-Noise Ratio，信噪比)及CNR(Contrast-Noise Ratio，对比度噪声比)等定量指标。

In order to obtain the weights of WWFM, an approach named Covariance Matrix Method is proposed to estimate the SNR of sources.

为获得该算法中的信噪比权值估计，提出估计目标源信噪比的"协方差矩阵方法"，获得较好的估计效果。

In chapterⅡ, considering GLMMs data which the number of high units is different and the number of low units is small and unbalanced, we Conduct a series of simulations, the simulations show that regardless of the number of the level 2 units,the Bayesian estimate of random effects residual variance is more precise than PQL and the PQL estimation deviates from the true value seriously; In terms of the fixed effects estimates, When the number of level 2 units is 20, The mean and median of the Bayesian estimate is more precise than PQL,But With the number of level 2 units increase,the estimate of two methods is similar. Thus, in practical applications, we recommend the use of Bayesian method.

第二章针对不同高水平单位数，低水平数较小且不平衡的GLMMs数据，进行模拟研究，研究表明：无论水平2单位数的大小，贝叶斯方法随机效应残差方差估计值远比PQL法更接近真实值，PQL法严重偏离了真实值；而对固定效应参数估计值，当水平2单位数为20时，贝叶斯法各参数的均数和中位数均要较PQL法更接近真实值，而随着水平2单位数的增加，两种方法在估计固定效应参数时相差并不大，因而，在实际应用中，推荐采用贝叶斯法。

Meanwhile, result comes out that seven fossil samples are mostly evergreen Araucarioxylon, deciduous species prapably exists, but their fixed numbers of growing year are extraordinarily variant; Analysis of ariance indicates that, imposing ray cells, radial tracheid diameters-, the ratios of ray cells to radial tracheid diameters on distinguishing seven samples is doable as a whole, while not fitting for individuals.

经方差分析可以看出，利用射线直径、管胞直径和射线管胞比可以在总体上区分各标本，但对个别样本不适用；射线高度这一性状在各标本间差别很小，不能区分；结果认为：标本2和标本6的性状最相近，为相同的种类；标本1、4、7可能为同一属；对方差和CSDM曲线的综合分析认为，标本1、3、6的生长年限存在一定的区别，可能导致在方差分析上出现些许误差。

The karyotype resemblance -near coefficients among the thirteen bivalves were computed according to the relative length and arm ratio of chromosomes. their average, mean square, extreme margin and standard deviation. The kindredship of thirteen bivalves were analyzed with the method of UPGMA.

方法］根据染色体相对长度、臂比，以及它们的平均值、方差、极差、标准差等参数，计算了13种双壳贝类之间的核型似近系数，用UPGMA法对它们的亲缘关系进行了聚类分析。

The influence of thickness d of ZnO varistors on the residual voltage ratio K \-r has been experimentally studied.It is showed that K \-r also has dimensioned effect. The results show that there is a residual voltage ratio K \-r decreases propor tonally with E \- 1mA ,and increase μ as grain mean size.

实验研究了厚度d 对ZnO压敏电阻片残压比Kr 的影响规律，表明残压比同样存在几何效应；实验还表明残压比Kr 随电位梯度E1m A成反比例下降，随平均晶粒尺寸μ的增大而增大；找到了一个综合微观结构参数平均晶粒尺寸μ和晶粒尺寸方差σ2 的乘积（σ2μ），能较好地反映电性能与微观结构参数的关系。

Through analysis of variance, the best mass ratio of different coating material matching is found out: It is the best matching when the mass ratioof red clay membrane urea is 5:7,which can lengthen the eluviationing time for 11 days, reduce the nitrogen eluviationing loss by 16.12%; the amount of the clay quality has no use to lengthen the eluviationing time and the result is not obvious; when the quality ratio of urea and gypsum is 5:8,it can lengthen the eluviationing time for 8 days, reduce the nitrogen eluviationing loss by 23.86%;when the quality ratio of urea and gypsum is 5:7,it can lengthen the eluviationing time for 30 days, reduce the nitrogen eluviationing loss by 16.58% when the contrast urea N is all eluviated out ; it is the optimum matching association; When the quality ratio of the urea and the sulfur is 5:6, which is a optimum proportion ,it can l

根据对淋溶时间、经济成本等的对比，经过方差分析，找出了不同包裹材料的最佳质量比的搭配组合：红胶泥包膜尿素的质量比是5：7时最好，可以延长淋溶时间11天，减少氮素淋溶损失16.12%；粘土质量的多少对延长尿素的释放时间作用不大，效果不明显；石膏和尿素两者的最佳质量比是5：8时，可以延长淋溶时间8天，减少23.86%的氮素淋溶损失；硼砂和尿素的质量比是5：7可以延长淋溶时间30天，当对照尿素N素全部淋出时，减少16.58%的氮素淋出，是最优

From these parameters, the new findings are:(1) The ice density from investigation is lower than 2-3 tenths compared with that from NOAA Ice Chart, and the ice thickness in the summer is less than 2 m compared with the results investigated during the First Chinese National Arctic Research Expedition in 1999 (CHINARE-1999);(2) The standing deviation of ice bottom fluctuation is 3.8 times of that of the snow surface on the ice sheet and (3) the maximum speed of ice floe CHIS7 is 1300 m/h in rotation and oscillation.

这些参数指出：现场调查的海冰密集度同NOAA冰图上的密集度相比低2~3成，而厚度比1999年的中国首次北极考察结果减少2m；冰层底面起伏方差约是冰层表面积雪起伏方差的3.8倍；浮冰最快以1300m/h速度运动并伴随振荡旋转。

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。