近似方法

The procedure of designing a FIR filter with the proximate best uniform approximation method is given.The example shows that the filter designed by this method is of good performance in both pass band ...

给出了用近似最佳一致逼近方法设计FIR滤波器的具体过程，然后通过实例表明该方法设计的滤波器在通带和阻带内具有较好的特性，且计算简单、计算量小，有较好的应用前景。

The numerical result demonstrates the Born Approximation can be effectively used for 3D imaging for borehole-ground electrical method. It also demonstrates that the method can be used as the basis for fast 3D inversion in reservoir monitoring application and in water injection exploration.

数值计算的结果表明Born近似是一种有效的井地电法三维快速反演方法，同时也说明井地电法监测油水前驱和储层边界预测的观测数据可以用该方法进行快速三维反演成像。

The phase of optical wave can be recovered by the intensity transport equation under the paraxial approximation For the optical system with diffraction limit, it is difficult to get the boundary radical slope of phase and sample in the circular domain boundary when using the intensity transport equation to recover the phase, consequently, we reviewed an algorithm mentioned in the reference ［4］, namely, the equation, computation domain and boundary condition are changed, then the phase is reconstructed by the multigrid method and corrected at last Moreover, the experiment system is set to testify the algorithm, and the recovered phase from the intensity data detected by CCD is compared with the result from phase retrieval algorithm, it is found that the phase reconstruction error can reach 017 λ in the case of non-uniform intensity distribution, as a result, the method is suitable for the phase recovery with low wavefront sensing accuracy.

在傍轴近似条件下，可以利用光强传播方程对畸变波前进行相位恢复。对于衍射受限的光学系统，很难获得相位的边界径向斜率值作为边界条件，此外，要获得精确的圆域边界采样值也并非易事。为了克服上述困难，进一步研究了相位恢复改进方法，即改变了方程的表示形式、计算区域和边界条件，并用多重网格法进行求解获得重构相位，最后再将其修正。为了验证算法的精确性，搭建了实验系统对算法进行实验验证，将由CCD探测的光强分布进行计算得到的相位分布与相位恢复算法的结果进行比较，证明在光强分布非均匀的情况下，该方法恢复的相位均方根误差能够达到017 λ，可以适用于波前传感精度要求不是很高的相位恢复。标签自适应光学相位恢复相位修正光强传播方程 adaptive optics phase retrieval phase correction intensity transport equation

By means of deriving the approximate solution and a process of approaching iteration, we have shown that a general solution exists for a non-Newtonian compressible fluid in 3D bounded domains. The proof is based on an elementary energy method.

文章利用构造近似解和极限的过程证明了三维有界区域中非牛顿可压缩流体广义解的存在性，所用的证明方法为能量方法。

New inspection method was deduced by using constant coefficient of variation in sequence inspection method, and the approximate relationship of inspection variables between mean method and sequence one was gained by analyzing difference of two methods.

将变差系数不变的条件引入到序贯检验方法中，推导出新的结构强度检验方法，分析检验变量与均值法的差异，得到两者的近似关系。

The approximate analytical solution may be expressed in terms of a rapid convergent power series with elegantly computable terms.

近似解结果和数值结果非常符合，证明了所提出的方法的准确性和可靠性，该方法可以用于解决其他科学和工程技术问题。

The governing equation of in-plane vibration of cable-restraint system is derived by means of D'Alembert principle, and then those partial differential equations are transformed into a set of ordinary differential equations by Garlerkin method. The method of Runge-Kutta integration is applied to solve the equation. The simulation analysis is made to prove that this vibration control has obvious damping effects and then the influence of cable tension, support mass, natural frequency and spring stiffness on the damping are discussed. Eventually, the approximate analytic solution of the optimum damping parameter is obtained to provide a simple and effective reference and design method for the engineers.

通过D'Alembert原理建立拉索－弹性约束系统振动方程，通过Galerkin方法将偏微分方程转化为常微分方程，应用龙格－库塔积分法求解方程；经过仿真分析，验证了该振动控制具有明显的减振效果，并且讨论了初始拉力、支座质量、振动频率及弹簧刚度对减振效果的影响；最后给出了计算最优阻尼参数的近似解析式，为工程师提供了简便有效的参考依据及设计方法。

ABSTRACT Fractal image coding, which is also called attractor image coding, is a emergent method of image compression during the last decad...

分形图像编码方法是近十年来诞生并发展起来的一种新型图像压缩方法，它将图像编码为一组收缩映射，由这组收缩映射的不动点近似待编码对象。

The approximation of field variable by RPIM is performed in a parameter domain. The shape function of RPIM possess Delta function's property.

该方法利用径向点插值方法，在参数域对每一个非样本点的支持域进行过点插值，构造出具有Delta函数性质的插值函数，能够实现参数域场变量的快速插值近似。

Meshless method is a new numerical method on problem for determining solution of differential equation. It is an approximation method based on nodes, and doesn't need a mesh entirely or partly. Then the discontinuous problems and the extremely large deformations problems can be solved without the re-meshing techniques.

无网格方法是求解微分方程定解问题的一种新数值方法，它采用基于点的近似，可以彻底或部分地消除网格，因此在处理不连续和大变形问题时可以完全抛开网格重构。

But we don't care about Battlegrounds.

但我们并不在乎沙场中的显露。

Ah! don't mention it, the butcher's shop is a horror.

啊！不用提了。提到肉，真是糟透了。