The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Cheng Yang-chun - One of the best experts on this subject based on the ideXlab platform.
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Laplace Inverse Transformation Based Semi-Analytical Solution of Coupling Currents of Transmission Line Illuminated by Electromagnetic Pulse
Power system technology, 2007Co-Authors: Cheng Yang-chunAbstract:According to the characteristics of the uniform plane wave, the distributed source generated on transmission line by external field can be regarded as the source delayed by that at the sending terminal. This retardation is the function of incident parameters of external field. On the basis of Taylor transmission line model and considering the retardation of distributed exciting sources under the excitation of uniform plane wave, the formulae of semi-analytical solution of current at receiving terminal of transmission line, which is composed of single lossless conductor and ideal ground, are derived in the Laplace domain; then by use of the property of Laplace Inverse Transformation, the semi-analytical solution of current in time domain is derived. Terminal coupling current varies with the transmission line parameters and incident parameter of spatial electromagnetic field. Simulation results show that the derived formulae for semi-analytical solution can converge quickly, and the derived formulae are available for reference to the research on the coupling mechanism of electromagnetic field to transmission line and on effect of parameters on the magnitude of coupling current.
Céline Robardet - One of the best experts on this subject based on the ideXlab platform.
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Tracking of a dynamic graph using a signal theory approach : application to the study of a bike sharing system
2013Co-Authors: Ronan Hamon, Pierre Borgnat, Patrick Flandrin, Céline RobardetAbstract:Dynamic graphs are useful objects to describe a network which evolves over time. We propose a signal theory approach to analyze them which consists of transforming the graph at each time step into a collection of signals and analyze these signals using spectral decomposition. An Inverse Transformation is also proposed and makes it possible to reduce the dimension of the graph and select the most significant edges. The method is applied on a real dynamic graph based on data about the bike sharing system Velo'v in Lyon. The analysis of signals representing the graph highlights the weekly cycle of rentals and the Inverse Transformation enables us to obtain sparser graphs.
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Tracking of a dynamic graph using a signal theory approach : application to the study of a bike sharing system
2013Co-Authors: Ronan Hamon, Pierre Borgnat, Patrick Flandrin, Céline RobardetAbstract:Dynamic graphs are useful objects to describe a network which evolves over time. We propose a signal theory approach to analyze them which consists of transforming the graph at each time step into a collection of signals and analyze these signals using spectral decomposition. An Inverse Transformation is also proposed and makes it possible to reduce the dimension of the graph and select the most significant edges. The method is applied on a real dynamic graph based on data about the bike sharing system Vélo'v in Lyon. The analysis of signals representing the graph highlights the weekly cycle of rentals and the Inverse Transformation enables us to obtain sparser graphs.
Runda Qian - One of the best experts on this subject based on the ideXlab platform.
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Correction to: Inverse Transformation based weighted fusion for face recognition
Multimedia Tools and Applications, 2018Co-Authors: Runda QianAbstract:In the original publication, the Equation 18 and its citation was incorrectly numbered as Equation 13. The original article has been corrected.
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Inverse Transformation based weighted fusion for face recognition
Multimedia Tools and Applications, 2018Co-Authors: Runda QianAbstract:Score fusion is a promising approach in face recognition. This paper proposes an algorithm that can integrate original images and virtual images. We obtain face-like virtual images that provide reverse representations of original face images by utilizing a new non-linear Transformation. Pixels with high intensities in original images correspond to pixels with low intensities in virtual images and vice versa. The correlation coefficient between the two kinds of data sources is relatively low, which indicates that the reverse face images are complementary to original face images. In this study, a linear model is used for calculating the distances between test samples and training samples, and all the distances are sorted in ascending order; we exploit the difference between the best score and the second-best score to calculate the weight. According to the experimental results, the proposed method outperforms other state-of-the-art methods in recognition accuracy and has a high computational efficiency.
Martin Schanz - One of the best experts on this subject based on the ideXlab platform.
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Boundary Element Calculation of Transient Response of Viscoelastic Solids Based on Inverse Transformation
Meccanica, 1997Co-Authors: L. Gaul, Martin SchanzAbstract:Mixed boundary value problems of solid mechanics are treated by numericalsolutions of Boundary Integral Equations (BIE) in time domain with theBoundary Element Method (BEM) thus reducing the spatial problem dimensionby one. Viscoelastic constitutive behaviour is implemented by means of aLaplace transform technique based on an elastic--viscoelasticcorrespondence principle. The concept of fractional differintegrationgeneralizes conventional constitutive equations and provides improvedcurve fitting of measured material response with fewer parameters. As theimplementation of viscoelasticity is provided in each time step in theLaplace domain, efficient algorithms for the Inverse Transformation intime domain are needed. This is why the performance of adapted algorithmsby Talbot, Durbin and Crump are compared. The impact responseof a base plate bonded on a viscoelastic soil halfspace is discussed as anumerical example. Viscous forces increase the velocities of surface wavepropagation and cause attenuation in addition to the so called geometricaldamping by radiation.
Li Xiu - One of the best experts on this subject based on the ideXlab platform.
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A New Algorithm of Full-Time-Domain of Inverse Transformation from the Transient Electromagnetic Diffuse Field into the Fictitious Seismic Wave Field
Chinese Journal of Geophysics, 2013Co-Authors: Qi Zhi‐peng, Li Xiu, Wu Qiong, Sun Huaifeng, Yang Zeng‐linAbstract:To realize 3D transient electromagnetic (TEM) inversion, we can transform the diffuse equations of TEM into wave equations, and then make pseudo wave imaging of TEM using seismic imaging methods. For such a Transformation, we adopt the preconditioned regularization conjugate gradient method to solve Inverse Transformation of the wave field. First, we compare several ways of discretization, and use the one with least condition number to make discretization of the equations. Then, we choose the optimal regularization parameters to make the wave field from Inverse transform stable and reliable, and use the super-relaxation pre-conditioned method to process the coefficient matrix to reduce its condition number. Finally, we employ the conjugate gradient method (RCG) to conduct iterative solving with a fast convergence. The comparison of Inverse Transformation results with known fictitious wave field functions shows that the algorithm is stable and convincing. Comparison with previous studies and application to real data indicate that the method suggested in this paper is correct and effective. Combined with the algorithm of Inverse Transformation, we also analyze the models with varied parameters and summarize the propagation rules of the fictitious seismic wave field in dispersion media.
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ICAIC (2) - An Optimized Method for Transient Electromagnetic Field
Communications in Computer and Information Science, 2011Co-Authors: Zhou Nan-nan, Xue Guoqiang, Li XiuAbstract:During the forward Transformation of wave-field, two-step optimized algorithm is used for decreasing the number of integral coefficients and sampling in dispersed digital integral, as while as ensure transient electromagnetic field’s calculation precision. This algorithm solves the ill-posed problem produced by large quantity of integral coefficients and depresses the ill character of the first calculation function. During wave-field Inverse Transformation, normalized algorithm is introduced to the Inverse Transformation by adopting the deviation theory and the Newton iterative form to make the transformed wave field stable and reliable. It is concluded that this algorithm is effective and useful.
