Browsing by Author "Sun, Shu-Hai"

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Envelope ADI-FDTD method and its application in three-dimensional nonuniform meshes
(2007-04-01)
Sun, Shu-Hai
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Choi, Charles T. M.
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資訊工程學系
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Department of Computer Science
The envelope alternating-direction-implicit finite difference time domain (ADI-FDTD) method in 3-D nonuniform meshes was proposed and studied. The phase velocity error for the envelope ADI-FDTD and ADI-FDTD methods in uniform and nonuniform meshes and different temporal increments were studied. A cavity problem was studied using the envelope ADI-FDTD and ADI-FDTD methods in graded meshes and the conventional FDTD method in a uniform mesh. The simulation results show that the envelope ADI-FDTD performs better than the ADI-FDTD in numerical accuracy.
Simulation of Axon Activation by Electrical Stimulation-Applying Alternating-Direction-Implicit Finite-Difference Time-Domain Method
(2012-02-01)
Choi, Charles T. M.
;
Sun, Shu-Hai
;
分子醫學與生物工程研究所
;
資訊工程學系
;
電機工程學系
In a typical approach to model electrical stimulation of an axon, a cable model equivalent to an axon was placed in a simple homogeneous medium. An electrode was used to induce an excitation to stimulate the cable model, and then the transmembrane potentials and the ionic currents in the cable model in temporal domain were observed. Unfortunately, this simulation approach is not realistic since inhomogeneous tissues near the axon is not considered. In this paper, the alternating-direction-implicit finite-difference time-domain (ADI-FDTD) method is coupled with the equivalent model of a membrane (the Hodgkin-Huxley model), and a novel simulation scheme is developed to predict axon activation. By testing axon activation with current excitation, the simulation results show the new method is useful for simulating axon activation.