查询词典 least squares

Firstly, the approach formulates a cost functional to turn the inverse problem into a constrained minimization problem according to least squares criterion, then the resulting constrained minimization problem is transformed into an unconstrained minimization problem by using a penalty function technique, and then the closed Fr chet derivatives of the Lagrange function with respect to the properties are derived based on the calculus of variations, finally, one can solve the resulting problem by using any gradient-based algorithm and the finite-difference time-domain method.

该方法首先以最小二乘准则构造目标函数，将逆问题表示为约束最小化问题；接着应用罚函数法转化为无约束最小化问题；然后基于变分计算导出闭式的拉格朗日函数关于特征参数的Fr chet导数；最后借助梯度算法和时域有限差分法迭代反演德拜模型参数。

Making use of the continuity of the shape function of moving least squares methods, this scheme can obtain fine fitting results and achieve multi-level continuous range image surface fitting, which are convenient for calculating surface characteristics of range image.

该方法充分利用最小二乘法形函数多阶连续的特点，能够保持在较高拟合精度的前提下获得深度图像曲面多阶连续的拟合结果，这种拟合结果为计算深度图像的曲面特性提供了便利。

This approach was to replace the derivative operator in the continuous time model by an approximation and estimation of the physical parameters of structures by the least-squares method.

讨论了导数近似值的选择方法，并分析了算法的收敛性。

Keywords Closed convex cone;gradient projection method;Least-squares solution;Inverse matrix problem;Inverse eigenvalue problem;Matrix completion problem;Optimal approximation

Article From 湖南大学；应用数学博士论文 2005年度闭凸锥；投影梯度法；最小二乘解；矩阵反问题；矩阵逆特征值问题；矩阵完全化；最佳逼近

In compressive sensing, the familiar least squares optimization is inadequate for signal reconstruction, and other types of convex optimization must be invoked.

在压缩传感，熟悉的最小二乘优化是不够的信号重建，和其他类型凸优化，必须援引。

In the roof reconstruction, a TIN-based region growing is applied to extract the roof planes. The coplanarity and adjacency between triangles are considered for TIN-based region growing. Then, a least squares regression is selected to determine the coplanarity function of planar segment.

在建物屋顶面重建中，使用建物轮廓线内部的光达点云进行屋顶面之共面分析，研究中使用三角网区域成长法侦测共平面之屋顶面，以相邻三角网法向量夹角做为共平面门槛，并以最小二乘法回归出屋顶面之平面，产生房屋模型。

The estimation bias is compensated by introducing a correction term in the recursive least squares estimate.

通过在递推最小二乘算法中引入一个修正项，补偿过程噪声引起的估计偏差。

On the basis of the theory of least-squares collocation, the approach used to define a local covariance function is described.

从最小二乘配置方法的原理出发，描述了最小二乘配置法中经验协方差函数的确定方法。

The elementary theory of Least-Squares Collocation in Physical Geodesy is described in detail in this thesis, as well as the method defining the covariance function, which is the key problem when utilizing LSC in physical geodesy.

本文描述了最小二乘配置法的基本原理及其基础理论，详细探讨了经验协方差函数的确定方法。

Secondly, by the P-L estimation of survivor function, this paper proposed the regression models of polynomial cumulative hazard function distribution models, respectively in the case of complete date and random right censoring date; meanwhile generalized least squares estimations of unknown parameters were proposed respectively using two steps algorithm and principal component analysis algorithm.

与已有的关于多项式危险函数模型的研究成果相比，首先本文在统计模型的构造上充分考虑了累积危险函数乘积限估计量的非独立性，给出了协方差矩阵的估计；其次在模型检验方面，本文利用非参数回归分析方法，充分利用了数据本身的信息，减少了对回归关系假定的主观因素，因而分析结果更为可靠。

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。