• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.58.2-58.2
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• 2019

Recent observation of the neutron star merger event, GW170817, through both gravitational wave (GW) and electromagnetic wave (EM) observations opened a new way of exploring the universe, namely, multi-messenger astronomy (MMA). One of the keys to the success of MMA is a rapid identification of EM counterpart through optical/NIR observations. We will present the strategy for prioritization of GW source host galaxy candidates to be observed with narrow-field optical telescopes. Our method relies on recent simulation results regarding plausible properties of GW source host galaxies and the low latency localization map from LIGO/Virgo. We will show the test results for both NS merger and BH merger events using previous events and possible future events and describe observing strategy with our facilities for GW events during the ongoing LIGO/Virgo O3 run.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.36.3-37
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• 2020

Recent observation of the neutron star merger event, GW170817, through both gravitational wave (GW) and electromagnetic wave (EM) observations opened a new way of exploring the universe, namely, multi-messenger astronomy (MMA). One of the keys to the success of MMA is a rapid identification of EM counterpart. We will introduce GW follow-up observation project in Korea for hunting GW EM counterpart rapidly and its strategy for prioritization of GW source host galaxy candidates. Our method relies on recent simulation results regarding plausible properties of GW source host galaxies and the low latency localization map from LIGO/Virgo. We will show a test result for both binary neutron star merger events using previous event and describe observing strategy with our facilities for GW events during the ongoing LIGO/Virgo O3 run. Finally, we report the results of optical/NIR follow-up observation of GW190425, the first neutron.

• Journal of electromagnetic engineering and science
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• v.6 no.2
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• pp.130-134
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• 2006

This paper presents the reduction characteristics of penetrated electromagnetic fields through a narrow slot in a planar conducting screen of infinite extent. When a plane wave is excited to the narrow slot, the aperture electric field is controlled by the parallel wire or parallel plate connected on the slot. The magnitude of penetrated electromagnetic fields through a narrow slot is controlled by electric field distributions on the slot. An integral equation for the aperture electric field on narrow slots is derived and solved by applying Galerkin's method of moments. The results show that the magnitude of the penetrated electromagnetic field can be effectively reduced by installing the parallel wire or parallel plate on the slot.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.2
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• pp.130-138
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• 1988

The method of conjugate gradient (C.G.M.) is applied to the solution of current distribution from body of revolution(B.O.R.). Using the C.G.M., it is possible to analyze electrically large arbitratily oriented B.O.R.. The fundamental differencess between C.G.M. and moment are outlined. This method converge for any initial guess, and this techniqe guarantees a monotonic convegence. Numerical resulsts are presented for electromagnetic case which shows good agreements with moment solution.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.13-17
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• 1987

Electromagnetic wave scattering from the two-dimensional scatterer was calculated by the Boundary Element Method (BEM). For the circular cylindrical scatterer, the BEM solutions agreed very well with the analytic solutions. The rectangular dielectric cylinder was also treated in the case of the lossy scatterer and the lossy medium.

• International Journal of Computer Science & Network Security
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• v.22 no.1
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• pp.295-299
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• 2022

In this paper, a fast numerical electromagnetic (EM) method based on the transverse wave formulation called-up Advanced Transverse Wave Approach (A-TWA) is presented. An appropriate 5G antenna is designed, simulated and investigated in the context of Millimeter-Wave Wireless Communication Systems. The obtained simulation results are found in good agreement with literature. Such a method can provide for the simulators a great library integrating the most complexly and sensitively geometry elements that can have a huge impact on the applications supported by new wireless technologies.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.10
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• pp.809-813
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• 2010

Frequency domain measurement of propagation loss for ultra high frequency (UHF) partial discharge in the winding of power transformer using a spectrum analyzer and pulse generator is presented. We compared the performance of the method using a network analyzer with and without a winding. Using a network analyzer simplifies the measurement and offers better dynamic range and frequency range. It also provides precise propagation loss within the winding in frequency domain at UHF range. We applied this method to measure UHF propagation loss of transformer mock-up, modeled 154 kV 20 MVA power in KEPCO substation.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.11
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• pp.874-879
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• 1991

The effect of air gap between specimen and jig on the material constant (permittivity, permeability) and attenuation characteristics of electromagnetic wave absorbers in the coaxial line method was investigated. The presence of a air gap made both permittivity and permeability measured lower than true value, and the tendency was greater in the case of permittivity. An inner gap compared to an outer gop was found to yield a larger difference between measured and true values. The effect of air gap was measured for a Ni0.3Zn0.7Fe2O4, with the gap eliminated by metallizing with Ag-paste. The measured characteristics were in good agreement with corrected values by calculation.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.12
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• pp.25-32
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• 1996

This paper is concenred with a finite volume time domain (FVTD) method for the analyses of transmission efficiency of electromagnetic wave propagation in tunnels with bend and fold. This method is gased on the volume integratio sof the maxwell's equation with respected to arbitrary shaped small polyhedron cells. The advantages of the present mehtod are that the algorithm is very simple since the coordinate system is restricted only to the cartesian, and so the arbitrary shaped boundaries can easily be dealt with since the fields at every center point of the cells are assigned in an average fashion.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.451-461
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• 2001

We present a simple design method of velocity-matched traveling-wave (TW) electrode with periodic capacitive loads. Once matching impedance and optical phase velocity are defined, the width and separation of coplanarstrip (CPS) and the magnitude and period of capacitive load are determined analytically. Calculation results of velocity-matched TW electrodes on GaAs substrates show bandwidths of more than 100 GHz.