The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Thomas Berger - One of the best experts on this subject based on the ideXlab platform.
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On perturbations in the leading Coefficient Matrix of time‐varying index‐1 DAEs
PAMM, 2012Co-Authors: Thomas BergerAbstract:Time-varying index-1 DAEs and the effect of perturbations in the leading Coefficient Matrix is investigated. An appropriate class of allowable perturbations is introduced. Robustness of exponential stability with respect to a certain class of perturbations is shown in terms of the Bohl exponent and perturbation operator. Finally, a stability radius involving these perturbations is introduced and investigated. In particular, a lower bound for the stability radius is derived.
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on perturbations in the leading Coefficient Matrix of time varying index 1 daes
Pamm, 2012Co-Authors: Thomas BergerAbstract:Time-varying index-1 DAEs and the effect of perturbations in the leading Coefficient Matrix is investigated. An appropriate class of allowable perturbations is introduced. Robustness of exponential stability with respect to a certain class of perturbations is shown in terms of the Bohl exponent and perturbation operator. Finally, a stability radius involving these perturbations is introduced and investigated. In particular, a lower bound for the stability radius is derived.
Suchuan Dong - One of the best experts on this subject based on the ideXlab platform.
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An Energy-Stable Scheme for Incompressible Navier-Stokes Equations with Periodically Updated Coefficient Matrix
Journal of Computational Physics, 2020Co-Authors: Lianlei Lin, Zhiguo Yang, Suchuan DongAbstract:Abstract We present an energy-stable scheme for simulating the incompressible Navier-Stokes equations based on the generalized Positive Auxiliary Variable (gPAV) framework. In the gPAV-reformulated system the original nonlinear term is replaced by a linear term plus a correction term, where the correction term is put under control by an auxiliary variable. The proposed scheme incorporates a pressure-correction type strategy into the gPAV procedure, and it satisfies a discrete energy stability property. The scheme entails the computation of two copies of the velocity and pressure within a time step, by solving an individual de-coupled linear equation for each of these field variables. Upon discretization the pressure linear system involves a constant Coefficient Matrix that can be pre-computed, while the velocity linear system involves a Coefficient Matrix that is updated periodically, once every k 0 time steps in the current work, where k 0 is a user-specified integer. The auxiliary variable, being a scalar-valued number, is computed by a well-defined explicit formula, which guarantees the positivity of its computed values. It is observed that the current method can produce accurate simulation results at large (or fairly large) time step sizes for the incompressible Navier-Stokes equations. The impact of the periodic Coefficient-Matrix update on the overall cost of the method is observed to be small in typical numerical simulations. Several flow problems have been simulated to demonstrate the accuracy and performance of the method developed herein.
Wuyang Zhou - One of the best experts on this subject based on the ideXlab platform.
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Improved GA solution on LNC Coefficient Matrix for multi-user cooperative communication
2012 IEEE 23rd International Symposium on Personal, Indoor and Mobile Radio Communications - (PIMRC), 2012Co-Authors: Sihai Zhang, Yuan Liu, Ming Zhao, Wuyang ZhouAbstract:Cooperative communication with network coding can yield higher system diversity gain and improve the efficiency of cooperation, for which designing the proper and efficient coding Coefficients is one key technique for implementation. The important contributions of our work reveal the existence of coding Coefficient Matrix of order M constructed in GF(M = 2n) and propose practical and effective method to search such Matrix. An improved genetic algorithm solution is proposed by introducing the local gradient search mechanism for large searching space and the search results show that the proposed method can obtain satisfying solutions and better computing performance for M = 8 in GF(8). The discussion on improved local gradient search mechanism illustrates its underlying potentials in global search framework. This work gains an insight into the Coefficient Matrix construction for cooperative communication with network coding in GF(2n).
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PIMRC - Improved GA solution on LNC Coefficient Matrix for multi-user cooperative communication
2012 IEEE 23rd International Symposium on Personal Indoor and Mobile Radio Communications - (PIMRC), 2012Co-Authors: Sihai Zhang, Yuan Liu, Ming Zhao, Wuyang ZhouAbstract:Cooperative communication with network coding can yield higher system diversity gain and improve the efficiency of cooperation, for which designing the proper and efficient coding Coefficients is one key technique for implementation. The important contributions of our work reveal the existence of coding Coefficient Matrix of order M constructed in GF(M = 2n) and propose practical and effective method to search such Matrix. An improved genetic algorithm solution is proposed by introducing the local gradient search mechanism for large searching space and the search results show that the proposed method can obtain satisfying solutions and better computing performance for M = 8 in GF(8). The discussion on improved local gradient search mechanism illustrates its underlying potentials in global search framework. This work gains an insight into the Coefficient Matrix construction for cooperative communication with network coding in GF(2n).
Lianlei Lin - One of the best experts on this subject based on the ideXlab platform.
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An Energy-Stable Scheme for Incompressible Navier-Stokes Equations with Periodically Updated Coefficient Matrix
Journal of Computational Physics, 2020Co-Authors: Lianlei Lin, Zhiguo Yang, Suchuan DongAbstract:Abstract We present an energy-stable scheme for simulating the incompressible Navier-Stokes equations based on the generalized Positive Auxiliary Variable (gPAV) framework. In the gPAV-reformulated system the original nonlinear term is replaced by a linear term plus a correction term, where the correction term is put under control by an auxiliary variable. The proposed scheme incorporates a pressure-correction type strategy into the gPAV procedure, and it satisfies a discrete energy stability property. The scheme entails the computation of two copies of the velocity and pressure within a time step, by solving an individual de-coupled linear equation for each of these field variables. Upon discretization the pressure linear system involves a constant Coefficient Matrix that can be pre-computed, while the velocity linear system involves a Coefficient Matrix that is updated periodically, once every k 0 time steps in the current work, where k 0 is a user-specified integer. The auxiliary variable, being a scalar-valued number, is computed by a well-defined explicit formula, which guarantees the positivity of its computed values. It is observed that the current method can produce accurate simulation results at large (or fairly large) time step sizes for the incompressible Navier-Stokes equations. The impact of the periodic Coefficient-Matrix update on the overall cost of the method is observed to be small in typical numerical simulations. Several flow problems have been simulated to demonstrate the accuracy and performance of the method developed herein.
Yixing Zhang - One of the best experts on this subject based on the ideXlab platform.
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On the Correlation Space of the Biproduct Coefficient Matrix Structure
IEEE Transactions on Communications, 2015Co-Authors: Norman C. Beaulieu, Yixing ZhangAbstract:The biproduct correlation Coefficient Matrix structure has gained acceptance and application in wireless communications. Yet, the set of correlation matrices that has this structure has not been fully identified. It is known that the positive equicorrelated Matrix satisfies the biproduct condition, but little else is known. The set of admissible correlation matrices having the special biproduct structure is investigated. Constraints on the signs of the correlation Coefficients that define the admissible set are revealed. Additional constraints on the magnitudes of the correlation Coefficients for admissibilty are also identified. The set of matrices satisfying the required structure is much more restricted than previously thought. The constraints are shown to become increasingly restrictive as the dimension $N$ of the correlation Matrix increases. The constraints also become more restrictive as the values of the correlation Coefficients increase to approach 1. Previously, only the equicorrelated Matrix has been identified as having the biproduct structure. Two additional correlation Matrix structures satisfying the biproduct structure are identified. Tests that exclude a correlation Matrix from having the biproduct structure are derived.