查询词典 approximation method

By using the spectrum approximation theory of compact operator, the approximation of anisotropic nonconforming ?nite element method for Stokes eigenvalue pronlem are presented and the optimal error estimates are obtained, which are as same as those of traditional ?nite element methods.

利用紧算子谱逼近理论，给出了 Stokes 特征值问题的各向异性非协调有限元逼近方法及最优误差估计，得到了与剖分网格满足正则性或拟一致性关键假设下相同的收敛效果。

In order to solve the problem,starting from the analysis of the simplest plane wave numerical theory,we derived the formula of relative phase velocity and group velocity under the condition of arbitrary high-order finite-difference approximation,and gave the computational method for acquiring the optimum Courant number,and then analyzed the anisotropic effects due to finite difference approximation.

针对此，从最简单的平面波数值理论分析出发，推导了任意高阶有限差分近似条件下相对相速度和相对群速度的计算公式，给出了求解最佳Courant数的计算方法，分析了差分近似造成的各向异性效应。

The Paper mainly studies forecast of a kind of time sequence which is made by using fuzzy approximation and Functional differential Equation, gives several theorems which explicate fuzzy and optimal approximation and relation between them by using the forecasting method.

主要对以模糊逼近和泛函微分方程进行时间序列预测问题作进一步的理论研究，给出了几个有关使用该预测方法时，模糊逼近与最佳逼近及其关系的定理，证明了逼近方面及预测方面的一些有意义的结果。

This paper describes a wavelet filter using wavelet transform method,it obtains the rational formula of wavelet function around the mathematical approximation of a mother wavelet. By using Mexican Hat wavlet as an example to simulate the approximation process and using Matlab to simulate.

本文描述了一种用小波滤波器实现小波变换的方法，它通过对母小波的一种数值逼近得到小波函数的有理公式，并以Mexican Hat小波为例来模拟这个逼近过程并用Matlab对逼近过程进行仿真。

The parallel line approximation -a new method for The approximation of demagnetizing field in magnetic-film of single domain is presented.

对磁记录中使用的磁阻传感器的磁阻效应进行了定量分析，并提出了一种新的单畴磁膜退磁场的近似计算方法──平行线近似。

The NIEL induced by low energy proton in Si and GaAs have been calculated using analytical method and Monte-Carlo code. Thin_target approximation was used when calculating NIEL by SRIM code and the result compared with that of other authors'. The results show that thin_target approximation is reasonable and NIEL scaling is feasible. The NIEL values become lower after taking into account the screening effect.

为此，本文采用解析法和基于Monte-Carlo方法的SRIM程序计算了考虑库仑屏蔽效应后低能质子在半导体材料Si，GaAs中的NIEL，SRIM程序在计算过程中采用薄靶近似法，并与其他作者的计算数据和实验数据进行了比较。

According to the characteristic that the definition point of the Q matrix of wave front is always located on the extremum point on the axis of the beam, a three-dimensional formula for the rectificative factor of phase in complex ray paraxial approximation is proposed, which calculates the rectificative factor of phase directly without considering the calculation of the main directions and curvatures and the rotation of the coordinates, thus simplifying the paraxial approximation calculation by the complex ray expansion method.

根据波前Q矩阵的定义点总位于波束轴上极值点的特点，提出了三维复射线近轴近似相位校正因子计算公式。该公式不用考虑主方向和主曲率的计算和坐标旋转，直接计算相位校正因子，从而简化了复射线展开法的近轴近似计算。

In this paper, a region approximation idea that means using a "fat curve" with a width to approximate the offset curve is proposed, and a complete set of algorithms to approximate offset curve using disk Bézier curve are given and implemented. In the algorithms, the optimal and uniform approximate curve of the offset curve as the central curve of the Disk Bézier curve is found by using Remez method, and then the upper optimal and uniform approximation principle is proposed to compute the error radius function of the Disk Bézier curve. Thus, the whole Disk Bézier curve can be obtained. In the end of this paper, the approximate effect of the Disk Bézier curve is not only analyzed and assessed, but also some specific examples are provided.

提出用一条带宽度的"胖曲线"来逼近上述等距曲线的区域逼近思想，并建立与实现了圆域Bézier曲线等距逼近的整套算法，包括应用Remez方法求出等距曲线的最佳一致逼近曲线作为圆域Bézier曲线的中心曲线，提出上控最佳一致逼近的原理求出圆域Bézier曲线的误差半径函数，以及确定整条圆域Bézier曲线，最后还对该圆域Bézier逼近的效果做了分析和考核，并给出了一些具体实例。

The approximation solution of the biomathematical model of muscular blood vessel under the condition of the nonresonant case is obtained. The expansion method for two variables of perturbation theory is used and the approximation solutions are given to the biomathematical model of muscular blood vessel under two cases.

求得了具有小阻尼、硬外激励的肌型血管生物数学模型在非共振情形下的一次近似解，并利用两变量展开法，经方程演化，求得了具有小阻尼、弱外激励的肌型血管生物数学模型在非共振和共振两种情况下的首次渐近解。

The method includes dividing a digital image, formed from M rows and N columns of pixels, into a plurality of band-shaped areas by partitioning at each of a prescribed number of rows; averaging, for each column, the gradation values of pixels in said band-shaped areas for each of said plurality of band-shaped areas; computing an approximation line which approximates, in each of said plurality of band-shaped areas, a distribution of said average of gradation values; and judging whether there exists a succession of d columns at which the difference between said gradation value derived from said approximation line and said average of gradation values for each column exceeds a prescribed threshold.

该方法包括：通过以规定行数为单位进行分割，将由M行N列个像素形成的数字图像划分为多个带状区域；对于所述多个带状区域的每一个，针对各列来对所述带状区域中的像素的浓淡值求平均；计算近似线，该近似线在所述多个带状区域的每一个中近似于所述浓淡值的平均值的分布；并且判断是否存在如下连续的d个列，在所述连续的d个列中，从所述近似线得到的所述浓淡值与针对各列的所述浓淡值的平均值之间的差值超出一指定阈值。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。