• The KSFM Journal of Fluid Machinery
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• v.20 no.1
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• pp.59-64
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• 2017

Diverter is an essential element in gravimetric calibration method of flowmeter. Error of diverter are influenced by flow velocity profile of nozzle outlet, motion velocity of diverter and detecting location. That's why, time detection position of diverter is tuned through repetitive test for minimizing error of diverter. Further the diverter must be compared with the other institutions test since the influence on the accuracy of the flow meter used in the test. In this paper, errors (flow velocity profile of nozzle outlet, motion velocity of diverter and detecting location) of diverter are decreased by produced uni-direction diverter and error of gravimetric calibration system is decreased. Uni-direction diverter is calibrated by gravimetric calibration system with precision flowmeter, the flowmeter is calibrated by pipe prover and other institutions and uni-direction diverter is evaluated. Uni-direction diverter is not influenced by flow velocity profile of nozzle outlet, motion velocity of diverter and detecting location. As a result, Uni-direction diverter can calibrate in wider scope since increasing ratio of maximum and minimum flow rate of uni-direction diverter.

• The Journal of Information Technology and Database
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• v.3 no.2
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• pp.119-132
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• 1996

웹을 이용한 클라이언트-서버 데이타베이스 시스템은 웹의 서비스 능력과 데이타베이스 시스템의 데이타 관리 기능을 상호 보완적으로 통합함으로써 인터넷과 같은 대규모 환경에서 데이타베이스 업무 환경을 구축하는 데 매우 적합한 것으로 알려져 있다. 데이타베이스 통로는 이러한 통합의 가장 핵심적 구성 요소이다. 본 논문에서는 먼저 클라이언트-서버 데이타베이스 응용을 위한 데이타베이스 통로의 고려사항으로서, 고성능 실행구조, 응용 프로그램 개발 환경, 그리고 상태 및 트랜잭션 관리에 대해 기술하고, 이어서 UniSQL/X용 데이타베이스 통로인 UniWeb 2.0의 설계와 구현에 대하여 소개한다. UniWeb 2.0은 CGI 응용 서버 방식을 채택하여 다양한 플랫폼을 지원하고, 고성능 그리고 확장성을 제공한다. 또한 프로그래머가 HTML 문서에 SQL/X문장이 포함된 Tcl 스크립트를 끼워 넣을 수 있도록 하여 응용 프로그램 개발 생산성을 향상시키고 있다. UniWeb 2.0은 여러 웹 페이지에 걸친 상태 와 트랜잭션을 지원하고 있다.

• Proceedings of the KIEE Conference
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• 2008.05a
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• pp.149-150
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• 2008

본 논문은 가로등 LED조명 설계를 위해 LED(Light Emiting Diode)소자 특성 분석 및 시뮬레이션을 통해 광특성을 개선하고자 하였다. $30^{\circ}{\sim}50^{\circ}$ 사이의 2차 렌즈 설계를 통해 조도 분포 특성 및 광분포 특성을 확인하였으며 LED 모듈의 간격 배열을 통해 램프를 설계 하고자 하였다. 그 결과 2차렌즈 35도 각도와 LED 소자간의 간격을 3Cm로 설정할 경우 최적의 광 특성을 확인할 수 있었다.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.151-153
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• 2008

This paper deals with the electric energy saving system for lighting with power conditioning, which aims at the integration of power quality improvement and energy saving. The system consists of a CCVSI(Current-Controlled Voltage Source Inverter) and VCVSI(Voltage-Controlled Voltage Source Inverter). The CCVSI is connected in parallel to a grid, which can be operated to compensate the reactive power demanded by nonlinear and variation loads. The VCVSI is connected to the CCVSI through the DC capacitor (DC side) and in series on the AC side(lighting load), which can perform the energy saving. The operation of the proposed system is confirmed through the simulation and its usefulness is discussed.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.418-420
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• 2003

The fault current limiting characteristics at the initial fault time for flux-lock type high-Tc superconducting fault current limiter(SFCL) were investigated. The amplitude of initial fault current of the flux-lock type SFCL was dependent on the inductance ratio of coil 1 and 2. After fault current limiting mode was analyzed, we compared the calculated value with the experimental one for the initial fault current. The effect of initial fault current due to the inductance ratio of coil 1 and 2 on fault current limiting characteristics was discussed.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1948-1950
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• 2005

In the recent years, much interests and attraction has been paid on the plasma display panel. To achieve high performance display panel, there has been a strong demands for studies on the transparent conducting films such as ITO and ZnO. In this study, we propose PDP cell with ZnO transparent conducting electrode. The electrical and optical characteristics of PDP cell with ZnO transparent electrode were studied and compared with that of conventional ITO electrode.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1219-1221
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• 2005

We improved quench properties of a superconducting fault current limiter(SFCL) components based on YBCO thin films. This consists of three components with nearly identical properties and one with slightly difference properties. The units were connected in series and first of parallel to increase the current and voltage ratings. It have caused significantly imbalanced power distribution. The imbalance remarkably improved by connecting a shunt reactor to the SFCL component in parallel.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.940-941
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• 2005

• Proceedings of the Materials Research Society of Korea Conference
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• 2006.11a
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• pp.19.2-19.2
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• 2006

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1546-1548
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• 2001

The $Sr_{0.8}Bi_{2.4}Ta_2O_9$(SBT) thin films are deposited on Pt-coated electrode(Pt/$TiO_2$/ $SiO_2$/Si) using RF magnetron sputtering method. With increasing annealing temperature from 600[$^{\circ}C$] to 850[$^{\circ}C$], Bi-layered perovskite phase was crystallized above 650[$^{\circ}C$]. The dielectric constant is 213 at annealing temperature of 750[$^{\circ}C$] and dielectric loss have a stable value within 0.1. Leakage current density is $1.01{\times}10^{-8}A/cm^2$ at annealing temperature of 750[$^{\circ}C$].