查询词典 covariance function

In the third chapter, 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. We consider three problems, the first one is when there exists no risk-free asset in the

第三章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

Many researchers have determined and estimated tree transpiration by using the methods of rapid weighting, steady-state porometer, photosynthesis system, whole-tree photometer, ventilated chamber, weighting potted-plant, sap flow measurements, lysimeter, water balance, energy balance, Bowen ratio, eddy covariance, Penman-monteith Method, and remote sensing.

针对不同的植被覆盖类型，国内外许多研究通过各种手段和方法，如快速称量、稳态气孔计、光合作用测定、整树容器、风调室、盆栽称量、液流测定法、蒸渗仪、水量平衡、能量平衡、波文比、涡动相关、彭曼联合法和遥感等来估算林木蒸腾作用。

A frame image of a video frequency sequence is read into a postpositional memory zone, and staring position and size information of a tracked object is obtained in the frame, then distribution statistical information of a target signature is extracted to build a gauss mixed model as an object template, a mean vector and a covariance matrix in gauss mixed distribution are used to describe the position and the size of the object, then the next frame image of the video frequency sequence is read into the postpositional memory zone. In a new frame video frequency image, a parameter estimation method is used to obtain object gauss mized model parameters in the current frame in iterative computation and find candidate template similar to the object template, and the final model parameters obtained in iteration are used to update the tracking window for realizing self-adaption of the tracked window.

将视频序列的一帧图像读入缓存区，获得该帧中被跟踪目标的初始位置和尺寸信息，然后提取目标特征的分布统计信息建立高斯混合模型作为目标模板，用高斯混合分布的均值向量和协方差矩阵描述目标的位置和尺寸，再将视频序列下一帧图像读入缓存区，在新一帧视频图像中利用参数估计方法迭代计算当前帧中目标高斯混合模型参数找到与目标模板最相似的候选模板，利用迭代得到的最终模型参数更新跟踪窗口实现跟踪窗宽的自适应。

Because of the computation load and the implementation complexity of full rank STAP are too great to be accepted and it is really very difficult to obtain enough samples to estimate the covariance matrix.

最初提出的是使用全部空域和时域进行处理的全时空的最优算法的计算量和实现的复杂度令人们难以接受，并且难以获得估计协方差矩阵所需的足够的样本数，后来的研究重点就转移到了降维处理算法上。

The performance of a disturbance covariance matrix is degradated in space time adaptive processing when it is estimated with secondary data contaminated by targetlike signals.

针对空时自适应处理中样本协方差矩阵受干扰目标污染时检测性能下降的问题，提出了一种基于知识的空时自适应处理（knowledge aided space time adaptive processing， KASTAP）方法。

To reach the aim, this paper designs a group of proper evaluation criterions on the basis of the qualitative and quantitative criterions, which is on the basis of visual interpretation, adopting average gradient and wavelet energy for analyzing the space resolution difference between fusion image and original undegraded multi-spectral image, adopting standard variance, standard deviation and covariance matrix determinant value for analyzing the difference of information between fusion image and original undegraded multi-spectral image, adopting mean, median and normalization least variance for analyzing the maintenance degree of spectrum information.

将待融合图像降解到原来分辨率的一半，用现有的一些融合算法进行融合实验，并用定性和定量评价方法对融合图像进行质量评价，得到10种较好的融合方法。

Unlike the uniform linear array,the unform circular array is able to provide 360°azimuthal coverage,within the mode space,it has the covariance matrix of the Toeplitz-like struture while all sources are uncorrelated,with which the noise variance can be made out directly,note that will eliminate an eigendecomposition when the ESPRIT is applied,consequently reduce the computational load.

对于均匀圆形阵列，在信源都是非相干信源的情形下，由于模式变换后的协方差矩阵具有类Toeplitz的特征，因此，我们可以根据这种特殊的性质，直接求得噪声分量，因此若使用ESPRIT算法进行波达方向估计，就可以避免第一次特征分解，较大程度上减少了计算量。

Another way infixing R2 into the M-V model results in violating the restriction of the M-V models, which the covariance matrix must be positive definite matrix, and then leads the performance of the portfolio to be worse eventually.

而另一种方式权重配置方式，将R2嵌入M-V模型方式所得出的结果，则违反了M-V模型的限制条件之一，即所变化后的共变异矩阵违反了正定的限制，最后使得投组的绩效变差。

Based on the scatted data , a suitable method has been proposed in this paper , in which the least eigenvector of covariance matrix for the local data points is used as the normal vector of the data .

这里针对散乱测量数据点云，以局部数据点协方差矩的最小特征向量作为数据点的方向矢量，并根据实际测量情况，对基于二次曲面拟合的数据点曲率估算算法进行了改进。

The data was analyzed by chi-square,stepwise regression analysis and covariance statistics.

资料用卡方检验、逐步回归和协方差分析等。

When I started coding, I had problems with the ASF file writer.

当我开始编码，我曾与ASF文件作家的问题。

I know that in one of the schools the boys have risen up in the classroom and enlisted in a mass.

如果你们也和他们一样，是集体自愿的话，你们的老师将是多么地光荣啊。