• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.398-400
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• 1987

Using the transmission line model, we have developed a formalism which is fairly accurate and convenient for analyzing the dispersion characteristics of rectangular dielectric waveguides for integrated optics. The fields in open half space regions are expressed as a Fourier integral form. Including all the TE and TM polarized discrete modes in slab waveguide region, our calculation shows that the discrepancies between the previous vectorial wave analysis using one discrete mode and the brute-force numerical analysis for the rectangular dielectric waveguides can be fully reduced with this method.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.7
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• pp.31-38
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• 1992

In this paper, numerical analysis package using Time-Domain Finite Difference (TDFD) method is developed to solve the initial value problem of Maxwell's equation and applied to several microstrip structures. TDFD allows us to show graphically the evolution of the crosswalk between microstrip lines. Moreover, we can obtain transmission line parameters and scattering parameters through Fourier transform of TDFD results in easy and efficient ways. TDFD is successfully applied to :1) wide band electromagnetic wave propagation along the single microstrip line, 2) crosswalk analysis between two microstrip lines, and 3) three metal line side-coupled filter. Our results show much better agreement with other theoretical experimental results reported in the literature. Thus we expect that TDFD is very useful to designing MMIC(Monolithic Microwave Integrated Circuit).

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.42 no.2
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• pp.23-28
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• 2005

This study was to suggest the propagation path loss and predictive model of propagation path analysis in order to apply the frequency in the millimeter-wave band to the real time inter-vehicle communication system. This study was to suppose the case of inter-vehicle communication on the one-way two-lanes road in the big cites with a lot of traffic jams in order to analyze the effect by the reflected wave of multipath. As a simulation of suggested model, it found out that the propagation path by the reflected wave was about 0.1[m]$\sim$5.1[m] longer than the one by the direct wave during the transmission of 100[m] wave direct path. Also, as a result of comparing the propagation path loss, the loss would be about -0.8[dB]$\sim$-4.2[dB] larger in case of wall reflection and -0.8[dB]$\sim$-1[dB] vehicle reflection. From the result above, this researcher found out that the path loss of reflected wave produced by the walls was about -3.2[dB] larger than the path loss produced by the adjacent vehicles.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.492-497
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• 2002

In this paper, Power Flow Analysis(PFA) method has been applied to the prediction of vibration energy density and intensity of coupled shell structures in the medium-to-high frequency ranges. To consider the wave transformation at joint between shell elements, power transmission and reflection coefficients are investigated for various joint angles, and here Donnell-Mushtari thin shell theory has been used. For validations computations are performed to analyze the response of coupled shells by changing the excitation frequency and damping loss factor.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.2049-2057
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• 2014

In this paper, a numerical method for analyzing coupling between high-altitude electromagnetic pulse (HEMP) as external field and a shielded twisted pair (STP) cable is proposed, which is based on an expanded chain matrix. Load responses of electromagnetic (EM) field excitation in uniform transmission line (TL) are solved by Baum-Liu-Tesche (BLT) equations in frequency domain, however, it is difficult to apply BLT equations to solve load responses of STP cable because the iteratively changing configuration of each twisted pairs are involved in cable. To avoid this problem and decrease memory and CPU time, we proposed the expanded chain matrix modeling method that is calculated using ABCD parameters, and applied multi-conductor transmission line (MTL) theory to consider the EMP coupling effectiveness of each twisted pairs. The results implemented by the proposed method are presented and compared with those obtained by the finite-difference time domain (FDTD) method as a kind of 3D full wave analysis.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.4
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• pp.29-40
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• 2004

This paper reports the frequency characteristics and the time response of parallel adjacent-transmission lines, crossed adjacent-transmission lines and parallel adjacent-transmission lines which are on the different planes by using FDTD-PML method. In the parallel adjacent-transmission lines, the crosstalks as a function of horizontal distance are calculated and in the crossed adjacent- transmission lines, the crosstalks as a function of vertical distance are simulated. Also, the crosstalks as functions of horizontal and vertical distances are measured and analyzed in the parallel adjacent-transmission lines which are on the different planes.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1422-1424
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• 2004

Various deterioration diagnostic techniques and devices are suggested, and most of which measure leakage current components as an indicator of arrester ageing. However, the techniques based on the magnitude of leakage current measure simply RMS or peak value of leakage current components and do not provide detailed information needed in the diagnosis. In this study, we found that the phase vs. wave height of total leakage current is changed or a new wave height is produced with arrester ageing. To complete the new technique, we designed an arrester diagnostic device which is composed of a current detection circuit, an optical transmission circuit, and an analysis program. After measurement of the total leakage current, magnitudes, phase vs. wave height, and harmonics of the leakage current components are analyzed by the microprocessor based device. From the experimental results, we confirmed that the device can measure most parameters needed for the arrester diagnostics and analyze an initial deterioration state.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.2
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• pp.167-174
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• 1996

In this paper, a fault location algorithm is presented, which uses novel signal processing techniques and takes a new paradigm to overcome some drawbacks of the conventional methods. This new method for fault location on electric power transmission lines uses only one-terminal fault signals. The main feature of the method is hat it uses the high frequency components in fault signal and considers the influence of the source network by using a traveling wave propagation characteristics. As a result, we can develop a high speed, good accuracy fault locator.

• Journal of Korean Port Research
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• v.8 no.2
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• pp.57-65
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• 1994

A theoretical formulation is performed to investigate the wave reflection and transmission ratios by a submerged multi-layered rubble-mound breakwater. This theory, which is based on the linear boundary integral method, can be extended to the multi-layered breakwater with arbitrary cross section. In the theoretical analysis evanescent mode wave is not considered, since fictitious open boundaries are put on the places far from the structure. Therefore the mathematical presentation may be simpler, and computational time shorter. The validity of obtained numerical results is demonstrated by comparing with ones of impermeable and permeable breakwaters. Comparison shows resonable agreement. On the basis of these verifications this theory is applied to the one and two-layered submerged rubble-mound breakwater with trapezoidal type.

• Journal of Communications and Networks
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• v.16 no.3
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• pp.305-310
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• 2014

Optimal position of access point (AP) is important for multi-gigabit wireless transmission in terahertz (THz) wireless local area network (WLAN)-type applications, where there exist the THz characteristic multiple clusters in channel propagation. By considering the multiple clusters in THz indoor communications, this paper investigates the optimal AP position when two APs are issued for increasing the system capacity. Numerical results reveal that the central position of each AP within each half service region, which offers the shortest cumulated path length for line-of-sight paths, is optimal to achieve the maximal system capacity.