共查询到18条相似文献,搜索用时 317 毫秒
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该文提出用快速多极子方法(FMM)求解三维非均匀介质散射体的电磁散射,将以往边界方程的FMM推广到三维矢量电磁波体积分方程(3DV-FMM),推导了一级和多级快速多极子的三维体积分离散公式。这一方法减少了计算机存储要求,并从量级上降低了共轭梯度迭代求解的矩量法的计算量。在计算中,选用函数作基函数,达到相当好的收敛性.本文用3DV-FMM数值计算了三维均匀和非均匀介质立方体,多个介质体的双站散射截面(RCS),以及任一剖面上的等效电流体密度分布。计算结果与矩量法相吻合,但在计算内存和CPU时间上要节省得多。本文的方法也可为三维电磁波逆散射的反演算法研究给出正向模拟的快速计算。 相似文献
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一种基于Sobel分解算子的图像边缘检测并行算法 总被引:4,自引:6,他引:4
付光远 《微电子学与计算机》2006,23(9):132-134
串行Sobel梯度算子边缘检测算法需要将两个掩模S1和S2分别在图像的每个像素上移动.并在每个像素上进行11次加法运算,即需要11xN^2次加法,时间复杂度为O(N^2);文章提出了一种Sobel算子分解模型。并设计了一种在SIMD—MPP模型上基于Sobel分解算子的并行图像边缘检测算法.该并行算法总共只需要8次平移操作和9次加法运算即可完成,其时间复杂度为O(1),加速比达到N^2,大大地提高了基于Sobel算子的图像边缘特征提取的效率。 相似文献
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三维各向异性介质目标电磁散射的MOM-CGM-FFT方法 总被引:12,自引:5,他引:7
给出了研究任意形状的三维各向异性介质目标的电磁散射问题一种混合计算方法。该方法以电场作为求知函数建立频域体积分-微分方程,使用脉冲基函数和点匹配函数的矩量法(MOM)将之转化为线性代数方程组。在求解过程中应用共轭梯度法9CGM)和快速富里叶变换(FFT)相结合的方法降低所需计算机内存和CPU时间。与各向同性和各向异性介质球的计算结果和解析结果及其它文献结果相比较,吻合较好。对材料参数为奇异矩阵的介质球的计算结果证明,该计算方法兼容性强,是一种求解三维电磁散射问题的有效途径。 相似文献
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An efficient static fast-multipole-method (FMM)-based algorithm is presented in this paper for the evaluation of the parasitic capacitance of three-dimensional microstrip signal lines above stratified dielectric media. The effect of dielectric interfaces on the capacitance matrix is included in the stage of FMM when outgoing multipole expansions are used to form local multipole expansions by the use of interpolated image outgoing-to-local multipole translation functions. The increase in computation time and memory usage, compared to the free-space case, is, therefore, small. The algorithm retains O(N) computational and memory complexity of the free-space FMM, where N is the number of conductor patches 相似文献
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WANG Zheng-bin ZHANG Ye-rongCollege of Mathematics Physics Nanjing University of Posts Telecommunications Nanjing ChinaCollege of Communication Information Engineering Nanjing University of Posts Telecommunications Nanjing China 《中国邮电高校学报(英文版)》2006,13(3):20-23
1 Introduction With the popularization of personal communication service (PCS), indoor radio propagation has attracted more attention, especially for ultra-wideband (UWB) signals. Ultra-wideband communication systems have very high data rates (at least 10… 相似文献
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An acceleration technique to the fast multipole method (FMM) has been proposed to handle large-scale problems of periodic structures in free space with finite sizes based on the accurate sub-entire-domain basis functions. In the proposed algorithm, only nine (or 27) elements in the whole impedance matrix are required to be computed and stored for a two-dimensional (or three-dimensional) periodic structure, and the matrix-vector multiply can be performed efficiently using the combination of fast Fourier transform and FMM. The theoretical analysis and numerical results show that both the memory requirement and computational complexity are only of the order of O(N) with small constants, where N is the total number of unknowns 相似文献
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Vande Ginste D. Rogier H. Olyslager F. De Zutter D. 《Antennas and Propagation, IEEE Transactions on》2004,52(10):2631-2640
An efficient fast multipole method (FMM) formalism to model scattering from two-dimensional (2-D) microstrip structures is presented. The technique relies on a mixed potential integral equation (MPIE) formulation and a series expression for the Green functions, based on the use of perfectly matched layers (PML). In this way, a new FMM algorithm is developed to evaluate matrix-vector multiplications arising in the iterative solution of the scattering problem. Novel iteration schemes have been implemented and a computational complexity of order O(N) is achieved. The theory is validated by means of several illustrative, numerical examples. This paper aims at elucidating the PML-FMM-MPIE concept and can be seen as a first step toward a PML based multilevel fast multipole algorithm (MLFMA) for 3-D microstrip structures embedded in layered media. 相似文献
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Makoto Ohki Haruo Sakurai Jun Horikoshi Syogo Kozaki 《Journal of Infrared, Millimeter and Terahertz Waves》1996,17(5):871-886
Exact solution of the electromagnetic wave scattering by N dielectric cylinders is presented by using matrix formulation. To check this present method, two comparisons between exact solutions for a single circular conducting and dielectric cylinder and this model composed of N=25 circular cylinders are made. Numerical results of conducting and dielectric square cylinder has been also checked with well-known result (B.E.M). The scattering patterns and the near field distributions in space are presented for the concave, convex and dielectric circular cylinder with conducting reflector. 相似文献
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Ooi B.L. Fan Y.J. Hristov H.D. Feick R. Xuechuan Shan Lu A. 《Antennas and Propagation, IEEE Transactions on》2008,56(5):1394-1401
The major computation cost of pseudo-spectral method comes from the evaluation of differentiation matrix multiplication. In the past, uniform or Chebyshev collocation points are used for sampling. The differentiation matrix multiplication was evaluated by fast Fourier transform (FFT) or fast cosine transform (FCT), in order to reduce the computation complexity from O(N2) to O(N log(N)). However, the intrinsic properties of FFT or FCT may cause the wraparound effect and Gibbs phenomenon. Moreover, FFT or FCT is not applicable to other collocation points such as Legendre and Hermite. In order to improve the accuracy and applicability of the pseudo-spectral method, the fast multipole method (FMM) is exploited to substitute the FFT or FCT. By making use of the similarity of the N-body problem and the collocation problem, a new FMM-based pseudo-spectral time domain method is developed in this paper. 相似文献
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A new kind of metron is proposed and rapid integration provided by fast multipole methods (FMM) is implemented to dramatically reduce the CPU time of finding the MEI coefficients in the on-surface measured equation of invariance (OSMEI) method. The numerical example of the scattering of a large conducting elliptical cylinder shows that the computation speed is at least one order of magnitude faster than that of the original OSMEI, where sinusoidal metrons are used, and about 25% faster than that of the FMM, where the iteration method is used. 相似文献