查询词典 covariance function

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。

The situation after the first M step is shown in plot, in which the mean of the blue Gaussian has moved to the mean of the data set, weighted by the probabilities of each data point belonging to the blue cluster, in other words it has moved to the centre of mass of the blue ink. Similarly, the covariance of the blue Gaussian is set equal to the covariance of the blue ink.

图显示了初始的 E 步骤，用红色表示用红色 component 产生的后验概率，蓝色也是同样的情况，还有一些不太确定的点是用紫色显示的，在图中蓝色的高斯的均值已经移到了蓝色数据集的中心上，类似的，蓝色高斯的协方差设为蓝色点的协方差。

This thesis has mainly contributed two results in theory: one is that the covariance matrix is not positive definitive if the number of sampling is least than the number of variables, the other is that the covariance matrix of discrete sample is positive definitive if and only if the sum of every random column vector of data matrix is non I-linear combination.

本论文在理论上，主要得出两个新的结果：ⅰ抽样调查中，若样本的个数少于变量的个数则样本协方差矩阵恒为非正定；ⅱ离散型样本协方差矩阵正定的充要条件是样本资料阵的各随机列向量是非I-线性组合。

On the basis of theoretical analysis of target diffusion in range-velocity resolution cell, the array signal covariance matrix and noise covariance matrix are estimated from some different cells respectively. The processing results from experimental data in onshore HFSWR with Minimum Variance Distortionless Respose, MUltiple SIgnal Classification and pre-whiten MUSIC respectively show that super-resolution methods can provide better resolution than CBF.

鉴于 HFSWR 工作波长较长、常规波束形成角分辨力较差的缺点，基于目标在距离—多普勒平面分布的理论分析，本文利用相邻距离、多普勒频率单元信号估计阵列协方差阵，并分别利用 MVDR 、 MUSIC 、预白化 MUSIC 方法进行超分辩处理，实测的合作飞机目标数据处理结果表明超分辩方法能明显提高阵列角度分辨力。

Unlike the previous method, however, the proposed algorithm obtains the new transformed matrix by taking the conjugate operation to the forward and backward spatial smoothing covariance matrix of the received data, so that the modified covariance differencing matrix which is a Hermitian matrix of zero real part can lower the computation load effectively during the eigenvalue decomposition.

不同于以前的算法，提出的算法通过对接收数据的前后向空间平滑协方差矩阵进行共轭运算得到新的变换矩阵，因此修正后的协方差差分矩阵是个实部为零的厄米特矩阵，从而有效地降低了特征分解过程的计算量。

Course contents include the analysis of variance and covariance, multivariate analysis of variance and covariance, principle component, factor analysis, cluster analysis, discriminant analysis, canonical correlation analysis, multidimensional scaling, discrete choice model, and LISREL.

其主要内容包括变异数与共变异数分析、多变量变异数分析、主成份分析、因素分析、集群分析、区别分析、规则相关分析、多元尺度法、二元质量选择模型、及 LISREL 模型。

Since the size of image covariance matrices is same as that of images and the within-class image covariance matrix is usual nonsingular, thus, the difficulty resulting from high dimensionality and singular case are artfully avoided.

该文提出了一种基于复向量进行特征表不的并行融合新策略，建立了复线性投影分析的理论，给出了复特征空间内进行线性特征抽取方法，事实上，经典的线性投影分析理论与方法只是本文理论与方法的一个特例。

For these important and practical problems,sample covariance matrix is an important statistic because many important statistics are functionals of it.When we make statistical inferences,such as estimations and/or hypothesis tests,the sample covariance matrices must be investigated.

以上诸多方面在做估计和假设检验过程中，无不用到大维随机矩阵的处理，尤其是大维样本协方差矩阵的相关性质，因为多元分析中许多重要的统计量都可以表示成样本协方差矩阵的函数。

For the case where the sample covariance matrix is unknown or the sample support is not sufficient to form the sample covariance matrix, we carry out the spatially smoothed CSA-MSWF to quickly find the signal subspace and the noise subspace.

如果阵列协方差矩阵是未知的，我们采用空间平滑的CSA-MSWF快速计算信号子空间和噪声子空间的基矢量。

First we construct a covariance matrix from sample images, then compute the eigenvalues and corresponding eigenvectors of the covariance matrix, construct a feature matrix with the eigenvectors. Then every images in database can be projected into the feature matrix and gain a projection vector, so does the input image. Then we can judge the resemblance between input image with each image in database by computing the distance between their projection vectors.

我们首先根据采集的样本图像构造一个协方差矩阵，然后求取该矩阵的特征值，以这些矩阵特征值对应的特征向量构造出一个特征空间，然后将输入图像向该特征空间映射，将获取的映射系数与样本库中图像的映射系数进行距离计算，根据计算出的距离判定输入图像与样本图像间的匹配程度。

In the days of sailing vessels the crew were afraid they would be becalmed on the ocean.

在使用帆船的时代，船员们担心他们会因为无风而无法在海洋上航行。

As long as foreign donors pay the PA's salary bill, few expect a new intifada.

只要外国继续为巴权力机构的薪水买单，希望发动新暴动的人便寥寥无几。