查询词典 approximation

The results of numerical experiments, using the four-dimensional variational data assimilation system of the nonhydrostatic mesoscale model MM5, show that: the tangent linear model and adjoint model conducted by keeping the "on-off" switches the same as the basic state, can provide a good approximation of the first-order information to the NLM perturbation and a good descent direction for the minimization procedure; switching on and off at every other time step in the Kuo cumulus parameterization scheme don"t impact the convergence rate of cost function; the existence of the switches don"t impact improvement to the MM5 model rainfall prediction because that not only specific humidity ,but also wind, temperature and pressure are assimilated into the model.

非静力中尺度数值模式MM5的四维变分资料同化系统进行的数值试验结果表明："开关"变量保持与基态一致，所构造的切向线性模式能够提供关于非线性模式扰动的一阶近似，伴随模式所计算的梯度值能够为最小化过程提供较好的下降方向；郭氏降水参数化方案中对流每隔一个积分步的交替发生并不影响目标函数最小化的收敛速度；"开关"变量的存在也不影响将风、温度、气压和比湿结合起来同化对MM5降水预报准确性的提高。

In the main-process, the coordinates of nodal points on part outline curve can be calculated by replacing this curve with a linear approximation. The codes expressed in NC program form which can be recognized by NC machine tool are got according to the coordinates of these nodal points in the post-process.

在前置处理中，用直线逼近零件轮廓，得到轮廓曲线的节点坐标：在后置处理中，根据这些节点坐标按照数控程序的格式得到数控机床可以辨认的程序代码。

This structure decreases the amount of non-zero quantified coefficients by iteration,and improves their approximation ability.

该结构通过迭代的方式减少了量化后的非零系数数量，并且提高了非零系数的逼近能力。

In this program, we focus on nonlinear approximation based on nonlinearity variation analysis.

中文摘要：非线性分析是智能系统理论研究中的重要内容。

Since the solutions of this problem are the critical points of the associated energy function. One generally needs some compactness such as PScondition or C-condition to prove the existence of critical points of the energy func-tion, but when we study the elliptic equation in R~N, the compactness condition does not always hold since the imbedding of the Sobolev space H_0~(1,2)into L~(2*) is not compact. In this chapter, based on the nonsmooth critical point theory, and by using the approximation technique with periodic function, the existence of nontrivial solution is obtained.

由于该方程的解就是其所对应的能量泛函的临界点，通常都要在一些紧型条件的基础上来证明其所对应的能量泛函临界点的存在性，但当我们在无界域上考虑该椭圆方程解的存在性时，Sobolev空间H_0~(1，2)到L~(2*)的嵌入非紧，从而导致所对应的能量泛函失去紧性，本章在非光滑临界点理论的基础上，应用周期逼近的方法证明该问题非平凡解的存在性。

By using the Tadmor's convergence criteria for the difference approximation of the hyperbolic conservative e2 quation and introducing some adjusting parameter in the nonvanishing viscosity , some convergence properties are obtained.

Descripción ：摘要：应用Tadmor 的关于双曲型守恒方程式差分逼近的收敛性判别法，对于若干差分逼近式，引入一些参数，只要在上机时适当调整此参数值，即可得到其收敛性。

Exive least-squares solutions, antire?exive least-squares solutions, bisymmetric least-squaressolutions, symmetric and antipersymmetric least-squares solutions, symmetric or-thogonal symmetric least-squares solutions, symmetric orthogonal antisymmetricleast-squares solutions and their optimal approximation to the linear matrix equa-tion AX = B, and solve them successfully. 2. For Problem II, we can convert it to another problem of finding the least-squares solutions with the least norm of a new consistent matrix equation. Onthe base of the solutions of Problem I we can apply the iterative method to get

本文所构造的迭代法的优点在于先利用法方程变换将求矩阵方程的最小二乘解转化为求一个相容矩阵方程的解的问题，再利用迭代法对于任意给定的初始矩阵进行迭代，均可在有限步内迭代出所求问题的一个解；可将问题II转化为求新方程的极小范数解的问题，同样用迭代法求解，从而系统且全面地解决了问题I、II在约束矩阵类如中心对称、中心反对称、自反矩阵、反自反矩阵、双对称、对称次反对称、对称正交对称、对称正交反对称矩阵中的最小二乘解及其最佳逼近问题。

Moreover, an offset approximation with high precision is obtained by degree elevation of the direction curve of normal.

因此关于等距曲线、曲面的研究，已成为 CAGD中的一个热门课题。

The ill-conditioned normal equations bring numerical problems in construction of macromodel in time domain for power distribution networking using rational function approximation.

摘要有理函数逼近法方程组病态条件数为构建电源分配网络时域宏模型带来了数值问题。

To evaluate the precision of solutions obtained by modal series method, normal form method and linear modal method, an error index describing the approximation to the nonlinear simulation is defined and then applied to the same system.

为比较模态级数法、正规形法和线性模式分析法所得解对时域仿真解的逼近程度，定义一误差指标，并在4机2区系统中做相关分析。

For the head-teacher of the class said that I had seriously broken the school rules,which led me to a three-day suspend class.

为什么呢？因为我的班主任说我严重的违反了校规，于是让我停课三天。

Many of them believe that the conversion of thousands of working-class folk in England spared that nation from the mass carnage and the tyranny that came with the revolution in France.

他们之中有许多人相信，在英国数以千计的劳工阶级之悔改信主使英国免於遭受如法国大革命所造成的大屠杀和专制暴政。