查询词典 continuous approximation

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 error analysis of asymptotic approximation of finite series expansion is also given. Our method avoids choosing the integral length of the reentrant comer, and can be used to calculate the charge on the conductor conveniently and efficiently. Numerical examples are presented to demonstrate the efficiency of the method.

本文算法克服了邓肯矫正需要选择角点积分区域的不足，有效地校正了导体角点奇异性引起的电容参数提取的计算误差，最后给出了算法的数值实验与分析结果。

The error analysis of asymptotic approximation of finite series expansion is also given. Ourmethod avoids choosing the integral length of the reentrant corner, and can be used tocalculate the charge of the conductor conveniently and efficiently.

该算法克服了邓肯矫正需要选择角点积分区域的不足，有效地校正了导体角点奇异性引起的电容参数提取的计算误差，且计算精度与稳定性都比较好。

Secondly, a asymptotic approximation formula of structurefailure probability is presented in generalized stochastic space with correlatedrandom variables by the asymptotic method of Laplace integral, by which the failureprobability and risk analysis on the chamfered vertical breakwater have been done.

其次，利用Laplace型积分的渐近计算方法，还推导出了广义随机空间相关荷载变量作用下结构失效概率的一个新的渐近计算公式，并依此算法对削角直立堤进行失效概率的计算以及风险评估。

Under the assumption that the channel state information was available only at the receiver,the capacity of MIMO systems in Rayleigh fading channel was investigated on the basis of information theory. Three special expressions for the MIMO capacity over ergodic flat fading channel were derived.An asymptotic formula for MIMO systems with equal number of transmit and receive antennas in small SNR was also given. Simulation results show that this approximation is relatively accurate.

以信息论的观点为基础，在假设信道状态信息仅收端已知的情况下，采用等功率发射方案，研究了瑞利衰落信道下MIMO系统各态历经信道容量，推导了三种特殊MIMO信道的各态历经信道容量表达式，以及在小信噪比下等收发天线MIMO系统的容量近似公式，并通过仿真进行了验证，仿真结果表明该近似公式比较精确。

Equidistance point and difference theory in theory of function approximation are studied. Meanwhile, the relation among difference, difference quotient and derivate is revealed. By drawing Lagrange's and Cauchy's theorem of mean on difference and Taylor's formula into difference function, four theorems, such as Lagrange's theorem of mean on difference, are concluded in simple way. On the basis of these conclusions, the asymptotic property of middle point is studied, a series of new conclusions are drawn and the discussions on the asymptotic property of middle point in differential mid-value are summarized.

对函数逼近论中等距节点和差分理论进行了研究，揭示了差分、差商与导数之间的联系；将Lagrange中值定理、Cauchy中值定理、Taylor公式引入到差分函数中，简明地推导出Lagrange差分中值定理等4个定理，并在此基础上对"中间点"的渐近性进行了研究，得出了一系列"中间点"的渐近性的结果，概括了有关文献对微分中值公式的"中间点"的渐近性的讨论；给出的引理改进了函数逼近论的证明方法，精简了函数逼近论中的一些内容。

In MA models, the likelihood function is so complicated that we just search a better estimate value in a range. Another method introduced is autoregression approximation method.

在滑动平均模型中，由于似然函数形式很复杂，这里采用逐一搜索的方法，本文介绍的另一种估计方法是自回归逼近方法。

"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。