The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Liming Zhang - One of the best experts on this subject based on the ideXlab platform.
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A nonconformal scheme for scattering analysis from PEC objects
Finite Elements in Analysis and Design, 2016Co-Authors: Ali Deng, Liming ZhangAbstract:A novel nonconformal scheme for electromagnetic scattering analysis from perfect electric conducting (PEC) objects is presented in this paper. In this nonconformal scheme, the Constant Vector basis functions defined on a single triangle element are used as basis functions to solve the magnetic field integral equation (MFIE). Several commonly used basis functions for the MFIE are discussed and it is shown that the use of the new basis functions for the MFIE is reasonable. The construction of Constant Vector basis function as well as details for the calculation of the admittance matrix elements resulted from the use of method of moments (MoM) to the MFIE are given. It is shown that the use of the Constant Vector basis functions to the MFIE results in an efficient nonconformal scheme. Numerical results further validate the effectivity and efficiency of the proposed nonconformal scheme. A simple nonconformal scheme for electromagnetic scattering is proposed.Several basis functions modeling surface electric currents are discussed.Practical applications of the proposed nonconformal scheme are presented.
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The use of the Constant Vector basis functions for the magnetic field integral equation
Engineering Analysis with Boundary Elements, 2015Co-Authors: Ali Deng, Liming Zhang, Minghong WangAbstract:Abstract The magnetic field integral equation (MFIE) is widely used in the analysis of electromagnetic scattering problems for conducting objects. Usually, the MFIE is solved by the method of moments (MoM) using the Rao–Wilton–Glisson (RWG) basis functions. In this paper, a new kind of basis function which is named the piece-wise Constant Vector basis function is proposed and used to solve the MFIE by MoM. Definition of this kind of basis function is given. The calculation of the impedance matrix entries is presented in detail. This kind of basis function is then used for the solution of the MFIE for electromagnetic scattering problems. The radar cross section (RCS) results and the iterative property of both kinds of basis functions are presented. It is shown that the piece-wise Constant Vector basis functions give similar RCS results as those of the RWG basis functions. Particularly, when iterative solver is used to solve the resultant linear system, the solution scheme using the piece-wise Constant Vector basis functions iterates much faster than that using the RWG basis functions.
Ali Deng - One of the best experts on this subject based on the ideXlab platform.
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A nonconformal scheme for scattering analysis from PEC objects
Finite Elements in Analysis and Design, 2016Co-Authors: Ali Deng, Liming ZhangAbstract:A novel nonconformal scheme for electromagnetic scattering analysis from perfect electric conducting (PEC) objects is presented in this paper. In this nonconformal scheme, the Constant Vector basis functions defined on a single triangle element are used as basis functions to solve the magnetic field integral equation (MFIE). Several commonly used basis functions for the MFIE are discussed and it is shown that the use of the new basis functions for the MFIE is reasonable. The construction of Constant Vector basis function as well as details for the calculation of the admittance matrix elements resulted from the use of method of moments (MoM) to the MFIE are given. It is shown that the use of the Constant Vector basis functions to the MFIE results in an efficient nonconformal scheme. Numerical results further validate the effectivity and efficiency of the proposed nonconformal scheme. A simple nonconformal scheme for electromagnetic scattering is proposed.Several basis functions modeling surface electric currents are discussed.Practical applications of the proposed nonconformal scheme are presented.
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The use of the Constant Vector basis functions for the magnetic field integral equation
Engineering Analysis with Boundary Elements, 2015Co-Authors: Ali Deng, Liming Zhang, Minghong WangAbstract:Abstract The magnetic field integral equation (MFIE) is widely used in the analysis of electromagnetic scattering problems for conducting objects. Usually, the MFIE is solved by the method of moments (MoM) using the Rao–Wilton–Glisson (RWG) basis functions. In this paper, a new kind of basis function which is named the piece-wise Constant Vector basis function is proposed and used to solve the MFIE by MoM. Definition of this kind of basis function is given. The calculation of the impedance matrix entries is presented in detail. This kind of basis function is then used for the solution of the MFIE for electromagnetic scattering problems. The radar cross section (RCS) results and the iterative property of both kinds of basis functions are presented. It is shown that the piece-wise Constant Vector basis functions give similar RCS results as those of the RWG basis functions. Particularly, when iterative solver is used to solve the resultant linear system, the solution scheme using the piece-wise Constant Vector basis functions iterates much faster than that using the RWG basis functions.
Young Ho Kim - One of the best experts on this subject based on the ideXlab platform.
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Some Classification of Canal Surfaces with the Gauss Map
Bulletin of the Malaysian Mathematical Sciences Society, 2018Co-Authors: Jinhua Qian, Young Ho KimAbstract:In this paper, we study canal surfaces in the Euclidean 3-space $$\mathbb {E}^{3}$$ in terms of their Gauss map $$\mathbb {G}$$ . We obtain a complete classification of canal surfaces whose Gauss maps are of the so-called pointwise 1-type, i.e., the Gauss map $$\mathbb {G}$$ satisfies $$\Delta \mathbb {G}=f(\mathbb {G}+C)$$ for a nonzero smooth function f and a Constant Vector C, where $$\Delta $$ denotes the Laplace operator.
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classifications of canal surfaces with l1 pointwise 1 type gauss map
Milan Journal of Mathematics, 2015Co-Authors: Jinhua Qian, Young Ho KimAbstract:In this paper, we study canal surfaces in the Euclidean 3-space \({\mathbb{E}^{3}}\) in terms of their Gauss map. We obtain a complete classification of such surfaces whose Gauss map G satisfies \({{\Box G = f(G + C)}}\) for a non-zero smooth function f and a Constant Vector C, where \({\Box}\) denotes the Cheng-Yau operator.
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classifications of helicoidal surfaces with l1 pointwise 1 type gauss map
Bulletin of The Korean Mathematical Society, 2013Co-Authors: Young Ho Kim, Nurettin Cenk TurgayAbstract:Abstract. In this paper, we study rotational and helicoidal surfaces inEuclidean 3-space in terms of their Gauss map. We obtain a completeclassification of these type of surfaces whose Gauss maps Gsatisfy L 1 G=f(G+C) for some Constant Vector C ∈E 3 and smooth function f, whereL 1 denotes the Cheng-Yau operator. 1. IntroductionLet Mbe a hypersurface of the (n+1)-dimensional Euclidean space E n+1 .A smooth mapping φ: M→ E N is said to be of k-type if it can be expressedas a sum of eigenVectors of Laplace operator ∆ corresponding to kdistincteigenvalues of ∆ ([6]). If φis an immersion from M into E n+1 is of k-type,then the submanifold Mis said to be of k-type ([3]). A good survey on finitetype submanifolds is [4].On the other hand, if the Gauss map Gof Msatisfies(1.1) ∆G= λ(G+C)for a Constant λ∈ Rand a Constant Vector C, Mis said to have 1-type Gaussmap, [7]. However, the Gauss map of some important submanifolds such as ahelicoid and a catenoid in E 3 satisfies a very similar equation to (1.1), namely,(1.2) ∆G= f(G+C)for a smooth function f ∈ C
Minghong Wang - One of the best experts on this subject based on the ideXlab platform.
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The use of the Constant Vector basis functions for the magnetic field integral equation
Engineering Analysis with Boundary Elements, 2015Co-Authors: Ali Deng, Liming Zhang, Minghong WangAbstract:Abstract The magnetic field integral equation (MFIE) is widely used in the analysis of electromagnetic scattering problems for conducting objects. Usually, the MFIE is solved by the method of moments (MoM) using the Rao–Wilton–Glisson (RWG) basis functions. In this paper, a new kind of basis function which is named the piece-wise Constant Vector basis function is proposed and used to solve the MFIE by MoM. Definition of this kind of basis function is given. The calculation of the impedance matrix entries is presented in detail. This kind of basis function is then used for the solution of the MFIE for electromagnetic scattering problems. The radar cross section (RCS) results and the iterative property of both kinds of basis functions are presented. It is shown that the piece-wise Constant Vector basis functions give similar RCS results as those of the RWG basis functions. Particularly, when iterative solver is used to solve the resultant linear system, the solution scheme using the piece-wise Constant Vector basis functions iterates much faster than that using the RWG basis functions.
Jon Wolfson - One of the best experts on this subject based on the ideXlab platform.
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Three-manifolds of Constant Vector curvature one
Comptes Rendus Mathematique, 2017Co-Authors: Benjamin Schmidt, Jon WolfsonAbstract:Abstract A Riemannian manifold has CVC ( ϵ ) if its sectional curvatures satisfy sec ≤ e or sec ≥ e pointwise, and if every tangent Vector lies in a tangent plane of curvature e. We present a construction of an infinite-dimensional family of compact CVC ( 1 ) three-manifolds.
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three manifolds with Constant Vector curvature
Indiana University Mathematics Journal, 2014Co-Authors: Benjamin Schmidt, Jon WolfsonAbstract:A connected Riemannian manifold M has Constant Vector curvature e, denoted by cvc(e), if every tangent Vector v ∈ TM lies in a 2-plane with sectional curvature e. When the sectional curvatures satisfy an additional bound sec ≤ e or sec ≥ e, we say that e is an extremal curvature. In this paper we study three-manifolds with Constant Vector curvature. Our main results show that finite volume cvc(e) three-manifolds with extremal curvature e are locally homogenous when e = −1 and admit a local product decomposition when e = 0. As an application, we deduce a hyperbolic rankrigidity theorem.
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Three-manifolds with Constant Vector curvature
arXiv: Differential Geometry, 2011Co-Authors: Benjamin Schmidt, Jon WolfsonAbstract:A connected Riemannian manifold M has Constant Vector curvature \epsilon, denoted by cvc(\epsilon), if every tangent Vector v in TM lies in a 2-plane with sectional curvature \epsilon. By scaling the metric on M, we can always assume that \epsilon = -1, 0, or 1. When the sectional curvatures satisfy the additional bound that each sectional curvature is less than or equal to \epsilon, or that each sectional curvature is greater than or equal to \epsilon, we say that, \epsilon, is an extremal curvature. In this paper we study three-manifolds with Constant Vector curvature. Our main results show that finite volume cvc(\epsilon) three-manifolds with extremal curvature \epsilon are locally homogenous when \epsilon=-1 and admit a local product decomposition when \epsilon=0. As an application, we deduce a hyperbolic rank-rigidity theorem.