• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.7
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• pp.1131-1138
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• 2001

This paper presents the new Compact 2D Haar-wavelet-based MultiResolution Time-Domain method (MRTD) as an accelerating algorithm for the conventional Compact BD Finite-Difference Time-Domain method (FDTD). To validate this algorithm, we analyzed the dispersion characteristics of the hollow rectangular waveguide and dielectric slab-loaded rectangular waveguide. The results of the proposed method are very weal agreed with those of both the conventional analytic method and the Compact 2D FDTD method. The CPU time for analysis of this method is reduced to about a half of the conventional Compact 2D FDTD method. The proposed method is valuable as a fast algorithm in the research of dispersion characteristics of waveguide structures.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1621-1626
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• 2003

This study deals with the heat transfer analysis on phase change optical disc with land/groove recording by means of numerical method. Finite difference time domain(FDTD) method was used to obtain the amount of absorption of light propagating inside disc and finite difference element(FEM) method was used to calculate the temperature distribution. The calculated results present the detailed information of recording characteristics on the phase change optical disc. The temperature profiles are quite different between the land track and the groove track. The recorded mark shape on land track is smaller and more elliptic than that on groove track. It is shown that the thermal problem to the neighboring track takes place due to secondary peaks. It is found that the different write strategy should be applied to land and groove recording, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.4
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• pp.328-335
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• 1996

The numerical dispersive characteristics and the numerical stability confition of the Multi-Resolution Time-Domain(MRTD) method are calculated. A dispersion analysis of the MRTD schemes including a comparison to Yee's Finite-Difference Time-Domain(FDTD) method is given. The superiority of the MRTD method to the spatial discretization is shown. The required computational memory can be reduced by using the MRTD method. We expect that the MRTD method will be very useful method for numerical modelling of electromagnetics.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.11
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• pp.28-33
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• 2002

In this paper, the impedance-tuned monopole microstrip antenna designed for PCS is analyzed using finite difference time domain(FDTD) method. The perfectly matched layer(PML) absorbing material condition proposed by Berenger is used for the truncation of finite difference time domain lattice. A Gaussian pulse is selected as an excitation signal and a resistive voltage source model is used to reduce the error caused by the reflection waves. The FDTD method is inherently a near field technique. Therefore, the near field to far field transformation is need to compute far field antenna parameters such as radiation patterns and gain. The near field to far field transformation can be done both in the time domain and the frequency domain. We use the frequency domain transformation to compute the far field radiation patterns at single frequency. All the numerical results obtained by the FDTD method are compared with simulation results using the HFSS software. Good agreements are obtained in all cases.

• Journal of electromagnetic engineering and science
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• v.8 no.4
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• pp.139-143
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• 2008

In this paper, a new scheme to calculate the weighting factor of the 2-D isotropic-dispersion finite difference time domain(ID-FDTD) is proposed. The weighting factor in [1] was formulated in free space, so that it may not be optimal in dielectric media. Therefore, the weighting factor was reformulated by considering the material properties and using the least mean square method. As a result, a minimum numerical dispersion error for any dielectric media is guaranteed.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.5 no.4
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• pp.30-39
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• 1994

The resonant frequency, reflection cofficient and input impedance of a microstrip transverse dipole coupled electromagnetically are calculated using Finite Difference Time Domain(FDTD) method, and the evolution of gaussian pulse and spatial distribution of electromagnetic field components in the computation domain is represented graphically. Also, we confirmed the computation results show good agreement with the results of Method of Moment(MOM) and experiment[8] reported in the literature.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.10
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• pp.1005-1011
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• 2011

In this paper, we present a marching-on-in-degree(MOD) finite difference method(FDM) based on the Helmholtz wave equation for analyzing transient electromagnetic responses in a general dispersive media. The two issues related to the finite difference approximation of the time derivatives and the time consuming convolution operations are handled analytically using the properties of the Laguerre functions. The basic idea here is that we fit the transient nature of the fields, the flux densities, the permittivity with a finite sum of orthogonal Laguerre functions. Through this novel approach, not only the time variable can be decoupled analytically from the temporal variations but also the final computational form of the equations is transformed from finite difference time-domain(FDTD) to a finite difference formulation through a Galerkin testing. Representative numerical examples are presented for transient wave propagation in general Debye, Drude, and Lorentz dispersive medium.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.8
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• pp.1997-2004
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• 1994

A model analysis method has been developed in the paper. The method estimates the modal parameters of multiple input-output systems, assesses their quality, and seperates structural modes form computation ones. The modal parameter extraction algorithm is the least squares method with a finite difference model relating input and output time data. The quality of the estimated system model can be assessed in narrow frequency bands by comparing the measured and model predicted responses in time domain with the aid of digital filters. Structural modes can be effectively separated from computational ones using the convergence factor which represents the pole convergence rate. The modal analysis method has been applied to simulated and experimental vibration data to evaluate its utility and limitations.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.23 no.1
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• pp.19-30
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• 2019

In this paper, we develop an accurate explicit finite difference method for the two-dimensional Black-Scholes equation with a hybrid boundary condition. In general, the correlation term in multi-asset options is problematic in numerical treatments partially due to cross derivatives and numerical boundary conditions at the far field domain corners. In the proposed hybrid boundary condition, we use a linear boundary condition at the boundaries where at least one asset is zero. After updating the numerical solution by one time step, we reduce the computational domain so that we do not need boundary conditions. To demonstrate the accuracy and efficiency of the proposed algorithm, we calculate option prices and their Greeks for the two-asset European call and cash-or-nothing options. Computational results show that the proposed method is accurate and is very useful for nonlinear boundary conditions.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.183-186
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• 2005

A two dimensional (2-D) finite-difference time-domain (FDTD) method based on a novel finite difference scheme is developed to eliminate the numerical dispersion errors. In this paper, numerical dispersion and stability analysis of the new scheme are given, which show that the proposed method is nearly dispersionless, and stable for a larger time step than the standard FDTD method.