Stephen D. Gedney

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In the context of the numerical simulation of seismic wave propagation , the perfectly matched layer (PML) absorbing boundary condition has proven to be efficient to absorb surface waves as well as body waves with non grazing incidence. But unfortunately the classical discrete PML generates spurious modes traveling and growing along the absorbing layers in(More)
Unsplit convolutional perfectly matched layers (CPML) for the velocity and stress formulation of the seismic wave equation are classically computed based on a second-order finite-difference time scheme. However it is often of interest to increase the order of the time-stepping scheme in order to increase the accuracy of the algorithm. This is important for(More)
Sparse solution of an integral equation formulation of scattering from open PEC targets, " Microw.ization of the impedance matrix in a localizing basis, " J. Electromagn. " Modular fast direct electromagnetic analysis using local-global solution modes, " IEEE Trans. direct solution of the electric field integral equation using non-overlapped localizing(More)
A SPICE lumped circuit subcell model is formulated within the discontinuous Galerkin finite-element time-domain (DGFETD) discretization of Maxwell's equations. A fourth-order exponential time difference (ETD) algorithm is used for circuits that lead to stiff systems. The ETD method reduces to a standard fourth-order Runge-Kutta (RK4) time-integration for(More)
Well-Conditioned Nyström-discretization of the volume integral equation for eddy current analysis, " IEEE Transactions on Magnetics, accepted. Eddy current analysis using a Nyström discretization of the volume integral equation, " Electric field-based surface integral constraints for Helmholtz decompositions of the current on a conductor, " IEEE(More)
Modulated ionospheric heating experiments are performed with the High Frequency Active Auroral Research Program facility in Gakona, Alaska, for the purpose of generating extremely low frequency (ELF) and very low frequency (VLF) waves. Observations are made at three different azimuths from the heating facility and at distances from 37 km to 99 km. The(More)
Due to the growing mismatch between processor performance and memory latency, many dynamic mechanisms which are " invisible " to the user have been proposed: for example, trace caches and automatic pre-fetch units. However, these dynamic mechanisms have become inadequate due to implicit memory accesses that have become so expensive. On the other hand,(More)
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