• Progress in Superconductivity and Cryogenics
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• v.11 no.3
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• pp.60-64
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• 2009

We investigated an operating characteristic of linear-type magnetic flux pump (LTMFP) as a current compensator under the various conditions. In order to explain the mechanism of the LTMFP, the magnetic behavior of superconducting Nb foil according to pumping actions should be understood. In this paper, the magnetic field analysis of superconducting Nb foil installed in LTMFP has been performed based on the three-dimensional finite element method (3D FEM). Through the simulation analysis, the normal spot region on the superconducting Nb foil is found to be enhanced swiftly over about 20 Hz. The simulated finding agreed with an analytical estimation based on the phenomenon of magnetic diffusion.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.519-522
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• 2000

Digital watermarking has been proposed as a solution to the problem of copyright protection of the multimedia documents. In this paper a new watermarking method for digital images operating in the frequency domain is proposed. In our approach, DCT coefficients of the watermark are added to the low frequency region of the host image, and extract it using the Wiener Filter. Due to the characteristic of the wiener filtering, the watermark is robust to various image processing techniques. Experimental results show that it is possible to reliably extract the watermark without degrading image quality.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.99-100
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• 2011

본 논문에서는 전압평면에서 표면 부착형 영구자석 동기전동기(Surface Mounted Permanent Magnet Synchronous Motor, SPMSM)의 전압과 전류 제한에 따른 운전 영역을 분석하고, 무한 속도 제한을 갖는 SPMSM에 적용 가능한 전압 궤환을 이용한 약자속 제어 기법을 제안한다. 제안된 기법은 시뮬레이션을 통해 그 타당성을 검증하였다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.5
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• pp.666-671
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• 1990

The characteristics of the corrugated conical horn antenna for the satellite communication earth station operating at C band is analyzed and its radiation patterns is measured. We obtain the characterstic equations for corrugated horn in the condition that the balanced hybrid mode is formed on born aperture and calculate radiation patterns in the Fresnel region from the aperture integral expressions obtained by the equivalence principle. The radiation patterns which are calculated for the frequency of 3.85GHz and 6.18GHz are well agreed with the measured data.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10b
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• pp.804-809
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• 1988

PRNM(Power Range Neutron Monitoring) of BWR (Boiling Water Reactor) is a system that processes signals from about two hundred LPRM (Local Power Range Monitor) sensors in the nuclear reactor and this system monitors the neutron flux level during the plant operating region. Development has been made by employing a special technique for multiplexing neutron sensor signals and the recent advanced microelectronics technology. It is applicable to the total plant digital control system for a nuclear power plant.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.309-312
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• 2000

In this paper, The Influence of chromatic fiber dispersion on the transmission distance of MMW(millimeter-wave) link is analyzed and discussed. It is shown that dispersion significantly limits the transmission distance in intensity modulated direct detection and heterodyne links operating in the above 20㎓ frequency region by inducing a carrier to noise penalty on the transmitted signal. We analyze and discuss the influence of dispersion induced CNR(Carrier to Noise Ratio) penalty for direct detection and heterodyne method from simulation.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.63-66
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• 2000

In this paper, we propose two new CMOS composite transistors with an improved operating region by reducing a threshold voltage. The proposed composite transistor 1 and 2 employ a P-type folded composite transistor and an electronic zener diode in order to decrease the threshold voltage, respectively. The simulation has been carried oui using 0.25$\mu\textrm{m}$ n-well process with 2.5V supply voltage.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.695-698
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• 2003

This paper presents a Si power LDMOSFET for power amplifiers in the 1.8-2.2GHz frequency range for the base station of personal communication systems. To improve the cut-off frequency, the proposed Si power LDMOSFET has small gate to drain capacitance by shielding the electric fields with extended source electrode and forming the field oxide structure in drain region. The proposed Si power LDMOSFET can be used for a power amplifier and it has 32% of power added efficiency and 39.5dBm of output power when the supply voltage is 28V and the operating frequency is 1.9GHz.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.305-308
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• 2000

In this paper, the 7${\times}$7 MMI Multiplexer is designed. The 1${\times}$7 Splitter and the 7${\times}$7 Coupler are designed and the phase-matched away length is determined. Then this result is confirmed by the simulation considering the intermode coupling. The MMI Multiplexer has The 14nm operating wavelength region, the 2nm wavelength spacing and the 1${\times}$3$\textrm{mm}^2$ size.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.87-90
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• 2000

In this paper. we present a method for a systematic design of a dielectric slab polarizer in the circular waveguide. This structure is realized using a tapered dielectric slab inside a circular waveguide. Commercial software is used to obtain the equivalent dielectric constant of the circular waveguide partially filled with a dielectric slab. The length of the tapered region is determined so that the reflection from the dielectric slab is sufficiently low. A polarizer operating at 10 GHz band is designed, fabricated and tested.