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Seraphin M. Mefire 《计算数学(英文版)》2014,(4):412-441
We are concerned, in a static regime, with a three-dimensional bounded domain of certain an imaging approach of the locations in electromagnetic imperfections. This approach is related to Electrical Impedance Tomography and makes use of a new perturbation formula in the electric fields. We present two localization procedures, from a Current Pro- jection method that deals with the single imperfection context and an inverse Fourier process that is devoted to multiple imperfections configurations. These procedures extend those that were described in our previous work, since operating for a broader class of settings. Namely, the localization is additionally performed for certain purely electric imperfections, as established from numerical simulations. 相似文献
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124.
周宝 《新疆大学学报(理工版)》2007,24(3):353-356
语音识别是通过对说话人语音信号的分析和提取.自动确定说话人是否在所登记的说话人集合中,以及说话的人是谁的过程.本文提出了一种基于特征提取技术的模板匹配语音识别算法.该算法中,采用与文本有关(主要用于时域分析)和与文本无关(主要用于频域分析)相结合的三种识别方法:快速傅立叶变换(FFT)、平均过零率分析(RBZ)和高斯混合模型(GMM),最后通过三种方法的加权平均来生成判决门限值.通过比较门限值误差的大小,根据“最大似然准则”给出待识别语音的身份. 相似文献
125.
假设二元随机函数X(x,y)表示具有指数为0〈H〈1的fBm。那么由fBm算法可生成一幅逼真的分形山图画。但是由于分形山本质上是由随机方法生成的,它的宏观形状和总体位置无法控制。本文给出一个谱综合方法,将有限网格上给出的二维曲面Y(x,y)的离散谱F↑ ̄(u,v)的低频分量与X(x,y)的离散谱F(u,v)的高频分量综合产生一个分形曲面Z(x,y)。其宏观形状及位置分布由Y(x,y)的低频控制。而 相似文献
126.
A semi-analytical method of solving the problem of dynamic stress concentration of arbitrary underground structure under the effect of blast waves was introduced. Using the Fourier transform theory, the shock waves (in the forms of SH-waves) can be converted into frequency bands. After employing complex functions and conformal mapping, the admittance functions of various underground structures were obtained. Then, the problem of the time domain dynamic stress response of underground structure can be easily solved through the Fourier inverse transform. At last, the results and curves of the dynamic stress for the square, triangle and horseshoe cavity were presented. 相似文献
127.
Xuanxuan Zhou Tingchun Wang Bingquan Ji Luming Zhang 《Mathematical Methods in the Applied Sciences》2019,42(9):3088-3102
In this paper, a conservative compact difference scheme is proposed for the two‐dimensional nonlinear Zakharov equation with periodic boundary condition and initial condition. The proposed scheme not only conserve the mass and energy in the discrete level but also are efficient in practical experiments because the Fast Fourier transform (FFT) can be used to speed up the numerical computation. By using the standard energy method and induction argument, we can establish rigorously the unconditional and optimal H2‐error estimates. Some numerical examples are provided to support our theoretical results and show the accuracy and efficiency of the new scheme. 相似文献
128.
Yutaka Maruyama Norio Yoshida Hiroto Tadano Daisuke Takahashi Mitsuhisa Sato Fumio Hirata 《Journal of computational chemistry》2014,35(18):1347-1355
A new three‐dimensional reference interaction site model (3D‐RISM) program for massively parallel machines combined with the volumetric 3D fast Fourier transform (3D‐FFT) was developed, and tested on the RIKEN K supercomputer. The ordinary parallel 3D‐RISM program has a limitation on the number of parallelizations because of the limitations of the slab‐type 3D‐FFT. The volumetric 3D‐FFT relieves this limitation drastically. We tested the 3D‐RISM calculation on the large and fine calculation cell (20483 grid points) on 16,384 nodes, each having eight CPU cores. The new 3D‐RISM program achieved excellent scalability to the parallelization, running on the RIKEN K supercomputer. As a benchmark application, we employed the program, combined with molecular dynamics simulation, to analyze the oligomerization process of chymotrypsin Inhibitor 2 mutant. The results demonstrate that the massive parallel 3D‐RISM program is effective to analyze the hydration properties of the large biomolecular systems. © 2014 Wiley Periodicals, Inc. 相似文献
129.
利用矩阵分块逐次降阶的方法和快速富里叶变换(FFT),给出了mn阶(R,r)-循环分块矩阵求逆与相乘的一种快速算法,证明了其计算复杂性为O(mnlog2mn). 相似文献
130.
Orthogonal wavelets enclose more potential of dropping the ISI- and ICI-sway amid the carriers due to multipath propagation over the free-space fading channels. Moreover, wavelet-OFDM is more bandwidth efficient as compared to conventional OFDM and is less affected by Doppler shift. Accordingly, a BER estimation of discrete Fourier transform (DFT) based OFDM system and discrete wavelet transform (DWT) based OFDM system is carried out in this work. The assessment is demonstrated by means of diverse modulation schemes explicitly BPSK, QPSK, 8-PSK, QAM, 8-QAM, 16-QAM for both conventional- and wavelet-OFDM wireless system over AWGN channels. Higher orders of PSK schemes involve more SNR requirement to target an acceptable BER of 10−5 over AWGN channels in both the cases. Furthermore, the efficiency of W-OFDM increases with decreasing the required value of BER. 相似文献