The Experts below are selected from a list of 94062 Experts worldwide ranked by ideXlab platform
Dan Jiao - One of the best experts on this subject based on the ideXlab platform.
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An unconditionally Stable Matrix-free time-domain method independent of element shape for multiscale and large-scale electromagnetic analysis
2016 Progress in Electromagnetic Research Symposium (PIERS), 2016Co-Authors: Jin Yan, Dan JiaoAbstract:We develop an unconditionally Stable Matrix-free time-domain method for analyzing general electromagnetic problems discretized into arbitrarily shaped unstructured meshes. This method does not require the solution of a system Matrix, no matter which element shape is used for space discretization. Furthermore, this property is achieved irrespective of the time step used to perform the time domain simulation. As a result, the advantage of a Matrix-free method in avoiding Matrix solutions is accentuated, while its shortcoming in time step's dependence on space step is eliminated, permitting an efficient analysis of large-scale and multiscale problems. Numerical experiments have demonstrated the accuracy and efficiency of the proposed method.
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accurate and Stable Matrix free time domain method in 3 d unstructured meshes for general electromagnetic analysis
IEEE Transactions on Microwave Theory and Techniques, 2015Co-Authors: Jin Yan, Dan JiaoAbstract:We develop a new time-domain method that is naturally Matrix free, i.e., requiring no Matrix solution, regardless of whether the discretization is a structured grid or an unstructured mesh. Its Matrix-free property, manifested by a naturally diagonal mass Matrix, is independent of the element shape used for discretization and its implementation is straightforward. No dual mesh, interpolation, projection, and mass lumping are required. Furthermore, we show that such a capability can be achieved with conventional vector basis functions without any need for modifying them. Moreover, a time-marching scheme is developed to ensure the stability for simulating an unsymmetrical numerical system whose eigenvalues can be complex-valued and even negative, while preserving the Matrix-free merit of the proposed method. Extensive numerical experiments have been carried out on a variety of unstructured triangular, tetrahedral, triangular prism element, and mixed-element meshes. Correlations with analytical solutions and the results obtained from the time-domain finite-element method, at all points in the computational domain and across all time instants, have validated the accuracy, Matrix-free property, stability, and generality of the proposed method.
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Accurate and Stable Matrix-free time-domain method independent of element shape for general electromagnetic analysis
2015 International Conference on Electromagnetics in Advanced Applications (ICEAA), 2015Co-Authors: Jin Yan, Dan JiaoAbstract:In this paper, we present a new time-domain method that is naturally Matrix free, i.e., requiring no Matrix solution, regardless of whether the discretization is a structured grid or an unstructured mesh. Its Matrix-free property is independent of the element shape used for discretization, and its implementation is straightforward. No interpolations, projections, and mass lumping are required. The accuracy and stability of the proposed method are theoretically analyzed and shown to be guaranteed. In addition, no dual mesh is needed and the tangential continuity of the fields is satisfied across the element interface. The flexible framework of the proposed method also allows for a straightforward extension to higher-order accuracy in both electric and magnetic fields. Numerical experiments have validated the accuracy and generality of the proposed Matrix-free method.
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Formulations of an accurate and Stable Matrix-free time-domain method in 2-D unstructured meshes
2015 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO), 2015Co-Authors: Jin Yan, Dan JiaoAbstract:In this paper, we present detailed 2-D formulations of a new time-domain method that is naturally Matrix free, i.e. requiring no Matrix solution, in an unstructured mesh. Numerical experiments demonstrate the accuracy and stability of the proposed Matrix-free method in arbitrary 2-D unstructured triangular meshes.
Edward J. Davison - One of the best experts on this subject based on the ideXlab platform.
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An Improved Bound on the Real Stability Radius
1992Co-Authors: Li Qiu, Edward J. DavisonAbstract:In this paper, we give a new lower bound on the real stability radius of a real Stable Matrix. We also conjecture that this new lower bound is equal to the exact value of the real stability radius.
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Bounds on the real stability radius
Robustness of Dynamic Systems with Parameter Uncertainties, 1992Co-Authors: Li Qiu, Edward J. DavisonAbstract:In this paper, we give a new lower bound on the real stability radius of a real Stable Matrix. We also formulate a nonlinear programming problem which can be used to obtain upper bounds for the real stability radius. Computational experience suggests that the new lower bound may in general turn out to be equal to the exact value of the real stability radius.
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A new method for the stability robustness determination of state space models with real perturbations
Proceedings of the 27th IEEE Conference on Decision and Control, 1Co-Authors: Li Qiu, Edward J. DavisonAbstract:The authors consider the robust stability of a linear time-invariant state-space model subject to real plant data perturbations. The problem is to find the distance of a given Stable Matrix from the set of unStable matrices. A novel method, based on the properties of Kronecker product and two other composite matrices, is developed to achieve this aim: The method makes it possible to distinguish real perturbations from complex ones. Explicit bounds on the distance of a Stable Matrix from the set of unStable matrices are obtained for both the continuous-time and discrete-time case. The bounds are applicable only for the case of real plant perturbations; hence they are less conservative to apply than for the case when complex perturbations are allowed. Several examples are given to demonstrate the new bounds, which in general are shown to be tighter than results previously reported. >
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The stability robustness of generalized eigenvalues
Proceedings of the 28th IEEE Conference on Decision and Control, 1Co-Authors: Li Qiu, Edward J. DavisonAbstract:The stability robustness of the generalized eigenvalues of Matrix pairs with real perturbations is considered. The problem is estimate the norm of the smallest destabilizing perturbation on a Stable Matrix pair. Sufficient conditions on the norm of the perturbations are given which guarantee the stability of the perturbed Matrix pair. The results obtained can be applied to the stability robustness analysis of singularly perturbed systems and descriptor systems and to a new kind of problem called the minimum phase robustness problem. >
Vicente Soler - One of the best experts on this subject based on the ideXlab platform.
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On the Construction of Analytic-Numerical Approximations for a Class of Coupled Differential Models in Engineering
2015Co-Authors: Emilio Defez, Vicente Soler, Roberto CapillaAbstract:In this paper, a method to construct an analytic-numerical solution for homogeneous parabolic coupled systems with homogeneous boundary conditions of the type ut = Auxx, A1u(o,t) + B1ux(o,t) = 0, A2u(1,t) + B2ux(1,t) = 0, ot>0, u (x,0) = f(x), where A is a positive Stable Matrix and A1, B1, B1, B2, are arbitrary matrices for which the block Matrix is non-singular, is proposed.
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On the Exact Series Solution for Nonhomogeneous Strongly Coupled Mixed Parabolic Boundary Value Problems
Abstract and Applied Analysis, 2014Co-Authors: Vicente Soler, Emilio Defez, Roberto Capilla, José Antonio VerdoyAbstract:An exact series solution for nonhomogeneous parabolic coupled systems of the type , where , and are arbitrary matrices for which the block Matrix is nonsingular, and A is a positive Stable Matrix, is constructed.
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On Exact Series Solution for Strongly Coupled Mixed Parabolic Boundary Value Problems
Abstract and Applied Analysis, 2014Co-Authors: Vicente Soler, Emilio Defez, José Antonio VerdoyAbstract:This paper continues with the construction of the exact solution for parabolic coupled systems of the type , , , , , and , where , , , and are arbitrary matrices for which the block Matrix is nonsingular, and is a positive Stable Matrix. Although this problem has been solved in the literature (Soler et al., 2013), in this work we are using completely new conditions.
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On Exact Series Solution of Strongly Coupled Mixed Parabolic Problems
Abstract and Applied Analysis, 2013Co-Authors: Vicente Soler, Emilio Defez, M. V. Ferrer, J. CamachoAbstract:This paper studies the construction of the exact solution for parabolic coupled systems of the type , , , , , and , where , , , and are arbitrary matrices for which the block Matrix is nonsingular, and is a positive Stable Matrix.
José Antonio Verdoy - One of the best experts on this subject based on the ideXlab platform.
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On the Exact Series Solution for Nonhomogeneous Strongly Coupled Mixed Parabolic Boundary Value Problems
Abstract and Applied Analysis, 2014Co-Authors: Vicente Soler, Emilio Defez, Roberto Capilla, José Antonio VerdoyAbstract:An exact series solution for nonhomogeneous parabolic coupled systems of the type , where , and are arbitrary matrices for which the block Matrix is nonsingular, and A is a positive Stable Matrix, is constructed.
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On Exact Series Solution for Strongly Coupled Mixed Parabolic Boundary Value Problems
Abstract and Applied Analysis, 2014Co-Authors: Vicente Soler, Emilio Defez, José Antonio VerdoyAbstract:This paper continues with the construction of the exact solution for parabolic coupled systems of the type , , , , , and , where , , , and are arbitrary matrices for which the block Matrix is nonsingular, and is a positive Stable Matrix. Although this problem has been solved in the literature (Soler et al., 2013), in this work we are using completely new conditions.
Jin Yan - One of the best experts on this subject based on the ideXlab platform.
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An unconditionally Stable Matrix-free time-domain method independent of element shape for multiscale and large-scale electromagnetic analysis
2016 Progress in Electromagnetic Research Symposium (PIERS), 2016Co-Authors: Jin Yan, Dan JiaoAbstract:We develop an unconditionally Stable Matrix-free time-domain method for analyzing general electromagnetic problems discretized into arbitrarily shaped unstructured meshes. This method does not require the solution of a system Matrix, no matter which element shape is used for space discretization. Furthermore, this property is achieved irrespective of the time step used to perform the time domain simulation. As a result, the advantage of a Matrix-free method in avoiding Matrix solutions is accentuated, while its shortcoming in time step's dependence on space step is eliminated, permitting an efficient analysis of large-scale and multiscale problems. Numerical experiments have demonstrated the accuracy and efficiency of the proposed method.
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accurate and Stable Matrix free time domain method in 3 d unstructured meshes for general electromagnetic analysis
IEEE Transactions on Microwave Theory and Techniques, 2015Co-Authors: Jin Yan, Dan JiaoAbstract:We develop a new time-domain method that is naturally Matrix free, i.e., requiring no Matrix solution, regardless of whether the discretization is a structured grid or an unstructured mesh. Its Matrix-free property, manifested by a naturally diagonal mass Matrix, is independent of the element shape used for discretization and its implementation is straightforward. No dual mesh, interpolation, projection, and mass lumping are required. Furthermore, we show that such a capability can be achieved with conventional vector basis functions without any need for modifying them. Moreover, a time-marching scheme is developed to ensure the stability for simulating an unsymmetrical numerical system whose eigenvalues can be complex-valued and even negative, while preserving the Matrix-free merit of the proposed method. Extensive numerical experiments have been carried out on a variety of unstructured triangular, tetrahedral, triangular prism element, and mixed-element meshes. Correlations with analytical solutions and the results obtained from the time-domain finite-element method, at all points in the computational domain and across all time instants, have validated the accuracy, Matrix-free property, stability, and generality of the proposed method.
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Accurate and Stable Matrix-free time-domain method independent of element shape for general electromagnetic analysis
2015 International Conference on Electromagnetics in Advanced Applications (ICEAA), 2015Co-Authors: Jin Yan, Dan JiaoAbstract:In this paper, we present a new time-domain method that is naturally Matrix free, i.e., requiring no Matrix solution, regardless of whether the discretization is a structured grid or an unstructured mesh. Its Matrix-free property is independent of the element shape used for discretization, and its implementation is straightforward. No interpolations, projections, and mass lumping are required. The accuracy and stability of the proposed method are theoretically analyzed and shown to be guaranteed. In addition, no dual mesh is needed and the tangential continuity of the fields is satisfied across the element interface. The flexible framework of the proposed method also allows for a straightforward extension to higher-order accuracy in both electric and magnetic fields. Numerical experiments have validated the accuracy and generality of the proposed Matrix-free method.
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Formulations of an accurate and Stable Matrix-free time-domain method in 2-D unstructured meshes
2015 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO), 2015Co-Authors: Jin Yan, Dan JiaoAbstract:In this paper, we present detailed 2-D formulations of a new time-domain method that is naturally Matrix free, i.e. requiring no Matrix solution, in an unstructured mesh. Numerical experiments demonstrate the accuracy and stability of the proposed Matrix-free method in arbitrary 2-D unstructured triangular meshes.