The boundary value integral equation and method of moments numerical technique is widely utilized for the study of electromagnetic scattering by arbitrary shaped conducting and penetrable objects. Even though this dir...
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The boundary value integral equation and method of moments numerical technique is widely utilized for the study of electromagnetic scattering by arbitrary shaped conducting and penetrable objects. Even though this direct approach is elegant as far as its application to analyze electrically largeobject is concerned, it inherently suffers from a wide range of computational difficulties. The method of moments system matrix is, in general, full and dense, requiring impractical demand on computer resources. In addition to operational numerical errors and ill-conditioning involved in the solution of large scale matrix equation, the direct numerical technique bears progressive degradation of accuracy of the near-field solution as the size of the system matrix increases. The apparent computational difficulties with the direct integral equation and method of moments has prompted an alternative numerical solution procedure based on the spatial decomposition technique. Using rigorous electromagnetic equivalence, the spatial decomposition technique virtually divides an electrically largeobject into a multiplicity of subzones. It permits the maximum size of the method of moments system matrix that need be inverted to be strictly limited, regardless of the electrical size of the large scattering object being modeled. The requirement on the computer resources is of order (N), where N is the number of spatial subzones and each subzone is electrically small spanning in the order of a few wavelengths. Numerical examples are reported along with comparative data and relative error estimation to expose applicability and limitation of the spatial decomposition technique for the two-dimensional scattering study of electrically large conducting and dielectric objects.
In this paper, we studied the efficiency and break-event point of storing video objects into DBMS and proved that storing "small" video objects into database is a suitable solution. To the video objects that...
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ISBN:
(纸本)9783642039959
In this paper, we studied the efficiency and break-event point of storing video objects into DBMS and proved that storing "small" video objects into database is a suitable solution. To the video objects that stored in database as BLOB data type, we devised a database based time-oriented approach to speed up the video content access. Our experiments showed that, because of we extracted some system-aware metadata and stored into database transparently, the read performance was become practicable.
A three-dimensional (3D) pre-corrected fast Fourier transform (pFFT) is presented for the fast analysis of electromagnetic (EM) scattering from electrically large perfect electrically conducting structures embedded in...
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ISBN:
(纸本)9781467318006;9781467317993
A three-dimensional (3D) pre-corrected fast Fourier transform (pFFT) is presented for the fast analysis of electromagnetic (EM) scattering from electrically large perfect electrically conducting structures embedded inside a planarly layered medium. The mixed-potential integral equation (MPIE) is used to formulate the problem and the method of moments (MOM) with Rao-Wilton-Glisson (RWG) basis function is employed to solve the integral equation. In order to avoid direct numerical computation of Sommerfeld integrals (SIs), the two-level discrete complex image method (DCIM) is employed to expedite the matrix filling process. In the iterative stage, the pFFT method is further adopted to accelerate the matrix-vector product, since the resulting matrix contains both cyclic convolution and correlation terms after proper splitting. Moreover, the incomplete LU preconditioner is applied to improve the convergence of the matrix equation. Numerical results are presented to show the efficiency and capability of the method.
A three-dimensional (3D) pre-corrected fast Fourier transform (pFFT) is presented for the fast analysis of electromagnetic (EM) scattering from electrically large perfect electrically conducting structures embedded in...
详细信息
ISBN:
(纸本)9781467317993
A three-dimensional (3D) pre-corrected fast Fourier transform (pFFT) is presented for the fast analysis of electromagnetic (EM) scattering from electrically large perfect electrically conducting structures embedded inside a planarly layered medium. The mixed-potential integral equation (MPIE) is used to formulate the problem and the method of moments (MOM) with Rao-Wilton-Glisson (RWG) basis function is employed to solve the integral equation. In order to avoid direct numerical computation of Sommerfeld integrals (SIs), the two-level discrete complex image method (DCIM) is employed to expedite the matrix filling process. In the iterative stage, the pFFT method is further adopted to accelerate the matrix-vector product, since the resulting matrix contains both cyclic convolution and correlation terms after proper splitting. Moreover, the incomplete LU preconditioner is applied to improve the convergence of the matrix equation. Numerical results are presented to show the efficiency and capability of the method.
Edge elements and a decomposition projective method are used to solve scattering problems of electrically largeobjects. A numerical example shows that approach is accurate and efficient.
ISBN:
(纸本)9781424470594
Edge elements and a decomposition projective method are used to solve scattering problems of electrically largeobjects. A numerical example shows that approach is accurate and efficient.
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