方差比

In functional optical imaging,the very low SNR makes the sample covariance matrix have singularity,which brings the whitening the operation of the ICA denoising method to reduce the dimensionality,so the ICA denoising method will lost the signal detection ability.

在光学功能成像中，极低信噪比会使得样本协方差矩阵具有奇异性，因此导致Emir等人提出的ICA去噪方法在白化预处理过程会出现降维现象，最终使得该方法无法检测出信号。

A new approach-two dimensional principal component analysis(2DPCA) is developed for face recognition. 2DPCA approach dont need to transform the image matrix into feature vector. It directly uses the image matrix to construct the sample covariance matrix.

5研究了二维主成分分析(2DPCA)方法，2DPCA方法不需要先将图像矩阵展开成一维向量，而是直接利用图像矩阵来构建样本协方差矩阵，所以2DPCA比PCA的识别时间更短，识别更高。

Also, a traditional test method is proposed by the Bartletts decomposition of sample covariance matrices and the sample mean vectors.

另外本文还利用样本协方差矩阵的Bartlett分解和样本均值，给出了检验共同均值的一种传统方法，这种检验犯第一类错误的概率比标称的检验水平略低。

The algorithm transforms the complex covariance matrix into a real matrix using an unitary transformation and then the real matrix is inversed and eigen-decomposed for adaptive beamforming so it has a low computation complexity in comparison with the ESB adaptive beamforming algorithm.

该算法利用酉变换将复协方差矩阵转换为实矩阵，然后对其求逆和特征分解进行自适应波束形成，因此其运算量比ESB自适应波束形成算法小得多。

Intra-/inter-specific spatial pattern: Four distribution measurements (variance/mean ratio, chi-square test, Clark-Evans index and Haberman residual analysis) were used.

分布格局分析采用四种方法：方差均值比、x〓检验、Clark-Evans指数和Haberman剩余分析，前2种属样方法，后2种属无样地法。

Consequently, there are many literatures on futures market searching the minimum variance hedge ratio.

相应的，有大量的关于期货市场的文献来寻找最小方差套期保值比。

With the consideration of the spatial variation of physical parameters of soft clay, the probabilistic characteristics of the one-dimensional average degree of consolidation of soft clay was studied and its sensitivity of variance to permeability, void ratio and compression coefficient of soil was also analyzed.

在考虑岩土参数空间变异性的情况下，对软粘土地基一维固结平均固结度的概率特征进行了研究，分析了平均固结度的概率特征对渗透系数、孔隙比和压缩系数三参数变异性的敏感性，进行了岩土参数分布类型对平均固结度影响的正交试验，并根据试验结果进行了方差分析，为进一步开展多层地基固结的可靠性分析打下了基础。

Results show that system performance is better than that without imitation, and system variance decreases with increasing imitational agent number N0 for small memory size m, which exhibits the validity of imitation.

研究发现，当记忆容量m较小时，系统表现比原始的少数者博弈模型要好。随着可参与模仿的经纪人人数N0的增加，系统方差呈下降趋势，体现出引入模仿的有效性。

MethodsFrom the biceps brachii, tibialis anterior and vastus medialis muscles,the duration, amplitude, area and the ratio of area to amplitude of the MUPs were obtained by use of the spike-wave triggered average technique in 10 patients with myopathic disease, 13 patients with neurogenic disease and 22 healthy adults.

选取 10例肌肉病变患者、13例神经病变患者和 2 2例正常人，采用棘波触发平均技术，获取肱二头肌、胫前肌和股内侧肌MUP的时限、波幅、面积和面积/波幅比 4项参数，通过SPSS10 。0软件进行方差分析和判别分析。

With the seeds from nine natural Cyclocarya paliurus populations as test materials, their phenotypic traits, including 1000-seed weight, seed size, seed diameter, seed thickness, and seed diameter/thickness ratio, were investigated, and the phenotypic diversity among and within the populations were studied by the methods of ANOVA analysis, hierarchical cluster analysis, and correlation analysis.

以青钱柳分布区内的9个天然群体种子为试材，对种子千粒重、体积、直径、厚度和径厚比5个表型性状进行了系统的比较分析，采用方差分析、相关分析及聚类分析等方法对群体间和群体内的表型多样性进行探讨。

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。