查询词典 first approximation

The output of this system is a reconstructed signal that is a good approximation of the desired waveform.

这一个系统的输出是被需要的波形的一个好近似值的一个被重建的信号。

This is true for an arbitrarily small electron-phonon coupling within the mean-field adiabatic approximation, which treats the phonon degree of freedom classically.

在电子半满情况下，晶格形成二聚化，基态具有二聚化长程序；在平均场近似下，声子自由度是经典的，对于任意小的电声耦合，都有Peierls相变，基态是二聚化的绝缘相。

This algorithm firstly translates arbitrary parameter curves into the piecewise cubic-degree Bezier curves, then using the properties of Bezier curve we can get the tangent vector and the normal vector of every point on the approximation curve, and calculate the approximating offset curve.

此算法先将任意形式的参数曲线转化成分段三次Bézier曲线，利用Bézier曲线的性质容易得到逼近曲线的切向量和法向量，从而计算出其等距逼近曲线。

In addition, we give the new form of emission area extraction functionΓ with HK approximation.

另外，我们还给出了面积获取函数Γ在HK近似下的新形式。

One bases on function value and another bases on arithmetic average difference quotient. In this paper, the author mainly studies the approximation properties of both the function value and the derivative of two kinds of splines interpolation mentioned before, and the optimal error constants are obtained finally.

文中分别就这两类插值样条的函数值及一阶导数的逼近性质展开讨论，相应得出这两种插值函数在被插函数分别为一阶连续可导和二阶连续可导情况下的最佳误差常数。

In design of floating-point division, we can use functional iteration arithmetic or very high radix division arithmetic. In the beginning, we use a look-up table to obtain an accurate initial reciprocal approximation, and reduce the time of delay.

在浮点除法器的设计中，若用函数迭代或高基数算法进行除法运算，计算开始时，通过浮点倒数查找表获得一个较精确的初始除数倒数近似值，可以减少除法的迭代次数，缩短运算的延迟。

Transmitting and receiving impulse response of two-dimensional array are obtained by the summing impulse response of a single rectangular element with differentia delay time. The approximation arithmetic of array element impulse response is discussed.

讨论了单阵元声场脉冲响应函数的快速近似算法，通过对不同延时量的矩形单阵元声场脉冲响应函数进行叠加，得到了二维换能器阵列的发射和接收脉冲响应函数，再施加以宽带脉冲激励函数，从而得到二维换能器阵列的声场分布。

According to the approximation ability of WNN, the nonlinear system is able to be modeled, obvious effect was shown in process modeling of residuum cracking and prediction of asphaltum yield and pyrolysis gas yield.

利用小波网络的逼近性，对非线性系统进行建模和预测，通过渣油裂解的实例，将小波网络与RBF网络作为对比，可以看出，小波网络的建模和预测效果都优于RBF网络。

Though comparing Canny operator and center B spline dyadic wavelet, the following conclusion is proven in this dissertation: a Center B spline function has tight support and Canny operator hasn't. b Center B spline function asymptotic convergence to Gaussian function and the derivative of Center B spline function asymptotic convergence to Canny operator. c The derivative of fourth order center spline B function is more suitable as a optimal edge detector than Canny operator. d Center B spline function can balance the smoothing and approximation of original data, and the fourth center B spline function is the only optimal solution of two order smoothing problem. e The error between the valve of time-frequency uncertainty of the fourth center B spline function and the lower bound of time-frequency uncertainty does not exceed 0.143% of the lower bound. f The derivative of center spline B function can construct a stability dyadic wavelet and can give a fast algorithm for multiscale edge detection, but Canny operator can do neither.

作者给出了Canny算子与中心B样条二进小波严格的比较证明，得出如下结论：a中心B样条函数具有紧支集，Canny算子不具有紧支集。b中心B样条函数的极限收敛于高斯函数，中心B样条函数的导数收敛于Canny算子。c四阶中心B样条函数的导数比Canny算子更接近最佳边缘检测滤波器。d中心B样条函数比高斯函数更能兼顾对原函数平滑和逼近的折中要求，并且四阶中心B样条函数是二阶逼近问题的唯一最优解。e四阶中心B样条函数的时频测不准关系值与时频测不准关系下界的逼近误差不超过0.143％。f中心B样条函数的导数可以构成稳定的二进小波，存在快速的多尺度算法；而Canny算子不构成稳定的二进小波，无法给出快速的多尺度算法。

Firstly, the Voronovskaja type formula of asymptotic expansion of this kind of operators is given. Then the approximation of the bounded variation functions by the kinds of operators is discussed.

第一节给出该算子的Voronovskaja型渐近展开公式；第二节讨论该算子对有界变差函数的逼近。

"The operators will suffer a temporary decrease in the number of consumers and short message services as people may not like having to provide their ID cards for a phone number," Xu Junqi, vice-dean with the Policy-Making Institute of the Telecommunications Research Centre under MII, said yesterday.

信息产业部下属的通信决策研究院副主任徐俊其昨天说：&实行手机实名制后，人们可能不太情愿用身份证注册手机号，所以通信运营商会暂时面临用户减少和短信用户减少的问题。&

I don't believe in make-believe!

我不相信这些虚构的故事。