• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.834-836
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• 2001

This paper deals with analysis for demagnetization characteristic of a ferrite magnet line start motor using FEM. Maximum start and clock currents are calculated by transient state voltage and dynamic equation, and then, these currents are applied to FE analysis. The characteristics of motor according to partial demagnetization are analyzed from FE analytic results, and rotor shape is designed for improvement of demagnetization characteristic.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.3
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• pp.497-502
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• 2012

Power line communication(PLC) is a kind of communication technology, was made use of controling a frequency narrow band, but as the PLC technology developing, in the near future get to the commercial step that is broadband PLC upto 30 MHz. This paper deals with the PLC of electric railway using capacitive signal coupler. An AC arrester for catenary is used as a capacitive signal coupler, has the characteristic of capacitor. As a result of field test, a messenger wire used PLC contain much of conducted noise about overall frequency band and also signal attenuation rate increased with increasing frequency between two points. and the communication speed of PLC used messenger wire is 793kbps at a distance of 40m. Experimental results show the possibility of PLC using a messenger wire and an AC arrester for catenary at electric railway.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.711-713
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• 2003

This paper deals with the improvement of starting characteristic of line-start synchronous relucatance motor(SynRM). To decide the number of conductor bars, the locking torque, when slip is 1, is computed by finite element method(FEM). And then, the magnetic circuit is designed to improve the starting torque according to the rotor position from the shape design of the conductor bars of the rotor with the flux barriers.

• Journal of Industrial Technology
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• v.21 no.A
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• pp.207-211
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• 2001

For the power line communication, we studied its characteristic impedance, noise characteristics, loss characteristics and the coupling circuit between the communication MODEM and power lines. As the results of the experiments, we concluded that the power line impedance in a house varied in the wide range because the electric systems generate the current and voltage hamornic noises.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.500-502
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• 2003

This paper reviews calculating of induced voltage onto a communication line from 22.9kV-Y Distribution Lines. The coexistence of both power line and communication line in parallel generates the induction of significant longitudinal voltage in the weak current line. In order to evaluate a precise induced voltage, this paper indicated some problems about coefficient and numerical formula. It also presents some induced voltage production technology standard application.

• Journal of Advanced Navigation Technology
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• v.13 no.5
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• pp.720-725
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• 2009

This paper proposes a modified Wilkinson power divider using a zero-degree composit right/left-handed(CRLH) transmission line to obtain a isolation between ports. A zero-degree CRLH transmission line, which has a total electrical length of zero, consists of a RH(Right-Handed) transmission line of a negative phase characteristic and a LH (Left-Handed) transmission line of a positive phase characteristic. To validate a value of zero-degree CRLH transmission line, the electrical lengths of RH and LH transmission line select $-30^{\circ}$ and $+30^{\circ}$ and a 2-way Wilkinson divider designed, we are measured S21 of -3.3dB, S11 of -27.5dB and S23 of -25dB at 1GHz center frequency. These characteristics are same the conventional divider using RH transmission line.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.1
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• pp.157-165
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• 2012

In this study, a short-wavelength transmission line employing periodically arrayed capacitive devices (PACD) was studied for application to miniaturized on-chip passive component on monolithic microwave integrated circuit (MMIC). The transmission line employing PACD showed shorter wavelength and lower characteristic impedance than conventional microstrip transmission line. The wavelength transmission line employing PACD structure was 8% of the conventional microstrip transmission line on GaAs substrate. Using the theoretical analysis, basic characteristic of the transmission line employing PACD (e.g., loss, effective dielectric constant, effective propagation constant, bandwidth ) were also investigated in order to evaluate its suitability for application to a development of miniaturized passive on-chip components on MMIC. Above results indicate that the transmission line employing PACD is a promising candidate for a development of miniaturized passive components on MMIC.

• Journal of Electrical Engineering and Technology
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• v.8 no.2
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• pp.262-270
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• 2013

A boundary protection method for power distribution line based on equivalent boundary effect is presented in this paper. In the proposed scheme, the equivalent resonance component with a certain central frequency is sleeve-mounted at the beginning of protected zone. The 'Line Boundary' is built by using boundary effect, which is created by introducing impedance in the primary-side of line. The 'Line Boundary' is significantly different from line wave impedance. Therefore, the boundary protection principle can be applied to power distribution line without line traps. To analyze the frequency characteristic corresponding to traveling-waves of introducing impedance in the primary-side of line, distributed parameters model of equivalent resonance component is established. The results of PSCAD/EMTDC simulation prove the obvious difference of voltage high frequency component between internal faults and external faults due to equivalent resonance component, and validate the scheme.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.2
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• pp.330-335
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• 2008

In this study, highly miniaturized short-wavelength transmission line employing periodically perforated ground metal (PPGM) structures were developed for application to miniaturized on-chip passive component on Si RFIC. The transmission line employing PPGM structure showed shorter wavelength and lower characteristic impedance than conventional coplanar-type transmission line. The wavelength of the transmission line employing PPGM structure was 57% of the conventional coplanar-type transmission line on Si Radio Frequency Integrated Circuit (RFIC) substrate. Basic characteristics of the transmission line employing PPGM structure were also investigated in order to evaluate its suitability for application to a development of miniaturized passive on-chip components. According to the results, it was found that the PPGM structure is a promising candidate for application to a development of miniaturized on-chip passive components on Si RFIC.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2005.11a
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• pp.166-167
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• 2005