查询词典 approximate method

In chapter 3, the author considers that approximate value of Bessel fuctions and transcendental equations are main ob stacle to realize computer simulation for isolated well principle. The character of Bessel functions are studied, new approximate values of Bessel function are set forth.

第3章中，针对"割离井法"微机实现的难点——贝塞尔函数的渐近计算和超越方程的合理求解，研究了贝塞尔函数的性质，提出了新的贝塞尔函数的渐近式，并采用ZEROIN法完成了超越方程的求解，最后编制出新的"割离井法"计算程序。

The Approximate time constant of the system is the sum of all the time constants of the one-order lags and for the biquadrafic lag system, and the approximate time constant is the first-order coefficient of the binomial.

不同的比例导引系数下，脱靶量归零的无量纲时间是一定的，即等效时间常数与末导时间呈线性关系，据此可以估算系统的末导时间。

In this paper, we expand the eigenvalue of Poisson equation using nonconforrn-ing Q1rot element. The principal term of error we get is not negative. In general, the approximate eigenvalue is the upper bound, but the approximate eigenvalue may be the lower bound when the principal term is zero.

本论文对Poisson方程的特征值采用方形旋转双线性非协调元Q_1~(rot元进行展开，得出的误差主项大于或等于零，因此在一般情况下近似特征值是上界，但当主项等于零时近似特征值可能是下界。

This work gives an algorithm to simplify the rational curves in this situation. After the approximate proper index is defined, it is computed by solving the semi-algebra system. The greatest common divisor is obtained according to the computing process of approximate proper index.

为此，讨论了这类有误差的有理参数曲线，定义了近似非恰当参数形式和近似非恰当指数，并通过半代数系统计算近似非恰当指数；在给出近似非恰当指数的同时，得到近似最大公因子。

Finally, to explain the advantage and shortcoming of nonparametric analysis and parametric analysis, and introduce some main shapes of nonpametric regression model: Fourier series, kernel estimators, and spline smoothing. In the meantime, we give the approximate theory and approximate distribution theory of these methods.

阐述了非参数回归分析和参数回归分析的优缺点，介绍了非参数回归模型的几种主要形式：富氏级数，核估计量和样条平滑，给出了这些方法的逼近理论和逼近分布情况。

Base on the fact that a hard-edge aperture function can be expanded into a finite sum of complex Gaussian functions, the approximate analytical expressions for the propagation characters of Hermite-Guassian beams passing through double rectangular apertured are derived. The approximate analysis uses Collins formula. At last, Matlab illustrates some numerical examples.

基于硬边孔函数能拓展成一组有限复高斯函数的和，研究厄米－高斯光束通过双矩孔的传输特性，用Collins公式分析，用Matlab进行一些数值模拟。

Isomap is one of the representative techniques of nonlinear dimensionality reduction.It extends classical multidimensional scaling by considering approximate geodesic distance. However,Isomap is sensitive to noise because the approximate geodesic distance is constructed on the basis of Euclidean distance. In this paper,a kernel-induced distance metric defined in the feature space is introduced instead of the Euclidean distance to evaluate the geodesic distance and construct the corresponding neighborhood graph.

采用核方法在特征空间推导出一类异于欧氏距离的新度量，代替等度规特征映射中的对噪声敏感的欧式距离，用新度量构造测地距离和相应的最小近邻图，提高Isomap算法的抗噪声能力。

If average values before or after catastrophe point when the pressure at both ends reduces exceed the threshold value, judging that there is leak and positioning: calculating approximate wavelet transformation coefficient of pressure data at both ends, initializing searching interval, calculating a signal time delay value corresponding to approximate wavelet transformation coefficient in the searching interval from maximal scale N; converting the time delay value under scale N to that under N-1 by geometric proportion relation; updating the searching interval, repeating above processes until the scale is 0 and positioning based on the time delay value.

若两端压力下降突变点前后的均值变化均超过阈值，判定有泄漏并进行定位：计算两端压力数据的近似小波变换系数，初始化搜索区间，从最大尺度N开始在搜索区间内计算对应近似小波变换系数的信号时延值，利用等比关系将尺度N下的时延估计值转换为N-1下时延估计值，以该值更新搜索区间，重复以上过程至尺度为0，以此时延估计值进行定位。

However, the solutions of the Cauchy problem of the nonlinear hyperbolic system generally develop singularities in finite time even if the initial data are small and smooth.For this reason, solutions must be found in the space of discontinuous functions. Therefore, one can not directly use the classical analytic techniques that predominate in the theory of partial differential equations of other types. Instead, we construct approximate solutions via the singular perturbation methods. By using the compactness of the approximate solutions, we can obtain the existence of the solutions of original system.

然而一般而言，即使是在初值很小且光滑的情况下，非线性双曲型守恒律的Cauchy问题的解在有限时间内也会出现奇异性，为此，我们必须在不连续函数空间中寻找上述问题的解，因此对这类问题的研究，我们也不可能直接利用在其它类型的偏微分方程中占主导地位的解析方法来解决问题，而是通过奇异扰动法构造近似解，由近似解的紧性得到原问题解的存在性。

As CMAC neural network could not be used to approximate the multi-valued mapping of an inverse hysteresis directly, an inverse hysteretic operator was proposed to transform the multi-valued mapping into a one-to-one mapping which could enable neural networks to approximate the behavior of an inverse hysteresis.

由于CMAC神经网络不能够直接逼近滞回逆这种具有记忆性的多映射现象，通过引入一个滞回逆算子，将多映射的滞回逆转换成一一映射，然后运用CMAC神经网络控制器来逼近这个一一映射，从而建立一个基于CMAC神经网络的滞回逆模型。

In contrast to the ubiquitous rising-sun-with-rays military flag of the Japanese, Chinese banners and ensigns feature a range of designs.

与遍地都是的太阳军旗不同，中国人的旗帜和徽章设计得各式各样。

From their small corner of Feng's Guangzhou headquarters -- a jumble of pink leashes, squeezable rubber steaks, and plastic doggy Santas for Fido's stocking -- Soleil's designers come up with at least five new products a month.

从Feng 设在广州总部的产品展示柜台上可以看到，Soleil的设计师每月至少设计出5件新产品。