查询词典 covariance

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。

Owing to the possible measurement error of variance and covariance for Markowitz's M-V model, in the present study, it employs two static models and two dynamic models, which are the sample covariance model, implicit factor mode!, implicit factor GARCH model and full-factor multivariate GARCH model.

基於Markowitz(1952)提出的M-V投资组合模型可能造成变异数及共变异数衡量的偏误，因此，本文以样本共变异数模型、内含因素模型等两我种静态模型，并参酌Alexander and Leigh(1997)的内含因子GARCH模型与Vrontos et al。

Pass to proceed the covariance to the unqualified article in quantity in product in factory rate first, analysis, find out to design the useful data to this, apply the in common use method that quantity manage completely, then adoption arrange the diagram proceeds the covariance to the unqualified article, making sure to cause unqualified and main reason in product, apply cause and effect analysis the diagram method finds out the main factor that affect the quantity, then make use of the scatter diagram, keeping the square diagram, controling the diagram to the main influence the factor proceed the analysis, evaluation, certain improvement counterplan, find out the best project, then proceed the technique economic evaluation.

首先通过对工厂产品质量不合格品率进行统计、分析，找到对本设计有用的资料，应用全面质量管理的常用方法，即采用排列图对不合格品进行统计，确定导致产品不合格的主要原因，应用因果分析图法找出影响质量的主要因素，然后利用散布图、直方图、控制图对主要影响因素进行分析、评价，确定改进对策，找出最佳方案，然后进行技术经济评价。

On the ground that the covariance between the disturbing gravity field elements is not isotropic, the covariance matrix has a complicated structure (its submatrix being not repetitive Toeplitz matrix) and thus its degree cannot be degraded with transformation matrix method, so it cannot be put into practice. So far, the application of least squares collocation to the modeling and data processing of the horizontal disturbing gravity field observations has not been found in literature.

由于水平扰动场元之间的协方差并非各向同性，导致协方差矩阵结构复杂(子矩阵不是 Toeplitz 循环阵)，不能利用变换矩阵将其降阶，无法付诸实践，迄今尚无最小二乘配置理论应用于水平扰动场元观测量的模型化公式和数据处理方法。

The algorithms of MUSIC and ESPRIT are introduced, which are the most important algorithms in array signal processing. A method is proposed to make the estimation of the covariance matrix become Toeplitz matrix using the Toeplitz characteristic of covariance matrix.

第2章建立了阵列信号的模型，主要分析了两种无方向模糊的阵列：阵元数大于6的均匀圆阵和非均匀L形线性阵列，并讨论了非均匀L形线性阵列无模糊设计的方法；然后介绍了在阵列信号处理中，两种最主要的算法：MUSIC算法和ESPRIT算法。

After studying this phenomenon, the author finds that, the covariance matrix of the complex expressions of horizontal gradients of the disturbing gravity field elements has a structure of blockwise repetitive Toeplitz matrix, though the covariance within the disturbing gravity field elements is still anisotropic. Therefore, the collocation problem of the complex combination of horizontal components is similar to that of gravity anomaly, which makes the degradation be able to be completed by FFT transformation matrix.

作者研究发现，利用水平梯度的复组合，即复数表示后，扰动重力场元复组合之间的协方差函数尽管还是各向异性，但它们对应的协方差矩阵却具有分块 Toeplitz 循环阵的结构，因而水平分量复组合的配置问题与重力异常的配置问题相似，可以利用傅立叶变换矩阵进行降阶处理。

In this paper we assume the expected returns of the risky and risk-free assets as well as the covariance matrix of the risky assets are not exactly known, but defined by some known elements, which form the vertices of this polytope. Robust optimal portfolio problems are proposed in the market with and without risk-free asset. And the analytical solutions are given out when the covariance matrix of the risky assets are exactly known.

本文假设风险资产和无风险资产的收益以及风险资产的协方差矩阵不是完全确定的，其相关参数属于某个已知的凸多面体，分别在市场不存在和存在无风险资产的情况下定义了稳健最优投资组合问题，并在协方差矩阵确定的情况下给出了问题的解析解。

Objective To investigate the effects of interleukin-1 β converting enzyme gene on the biologic characteristics of ovarian cancer cells.

目的 探讨白细胞介素-1 β转换酶的表达，对卵巢癌细胞生物学特性的影响。

Campylobacter: This illness is the most commonly identified cause of diarrheal illness in the world.

弯曲：这种病是最常见的原因查明腹泻病，在世界上。