• 천문학논총
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• 제14권1호
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• pp.47-56
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• 1999

We have improved the control and driving system of 16' reflector at Kwanak Observatory at Seoul National University, by completing encoder unit, and by developing programs for correction of errors resulting from hardware defects. The hardware defects of this telescope system are the large backlash and the nonuniform tracking and pointing. The telescope pointing accuracy for RA is improved to a few arc minutes, and that for DEC is several tens of arc minutes. The guiding error is improved to 0.7 arcsec/minute, allowing up to 3 minutes exposure for CCD imaging under typical seeing conditions at the Observatory.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.913-916
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• 2006

The improvement of luminous efficacy is one of the major issues in PDP industry. In this work, we propose the new driving method for high efficiency AC-PDP and analyze its discharge characteristics. The suggested method can control the effective capacitance of panel by external auxiliary capacitor. External capacitor induces reduction of gap voltage proportional to the panel current, this in turn modifies the transient behaviour of discharge. The peak current level is reduced and the discharge duration is increased. As a result of these modifications, the luminous efficacy is enhanced by about 200% compared with the conventional driving method

• 한국전기전자재료학회논문지
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• 제22권4호
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• pp.323-326
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• 2009

We have developed blue-emitting phosphorescent organic light emitting diodes (OLEDs) using 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and tris (8-quinolinolato)aluminum ($Alq_3$) electron transport layers. As blue dopant and host materials, bis[(4,6-di-fluorophenyl)-pyridinate-N,C2']picolinate (FIrpic) and N,N'-dicarbazolyl-3,5-benzene (mCP) were used, respectively. The driving voltage, current efficiency and emission characteristics of devices were investigated. While the driving voltage was about $1{\sim}2$ V lower in the device with an $Alq_3$ layer, the current efficiency was about 66 % higher in the device with BCP electron transport layer. the blue phosphorescent OLED with BCP layer exhibited higher purity of color, resulting from a relatively weak electroluminescence intensity at 500 nm.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1034-1037
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• 2002

A switched-capacitor(SC) type DC-DC converter having capability of integrated circuit fabrication have been marked for the application of mobile equipments. Especially, a ring type SC power supply is featured by the flexible and dynamic voltage conversion ratio change. In this paper, an improvement of the gate driving techniques is proposed for high power efficiency and less area occupation on the chip. Furthermore, its power-saving operation in the stand-by state is proposed. The three-capacitors ring type power supply is really designed and discussed. As results, the simulation results shows the high efficiency of 92.1%, and the higher output put voltage of 10.5 V compared with conventional one of 8.6 V.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.988-991
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• 2003

In this paper, we try to develop the controller which uses the block diagrams of SIMTool and internal functions CEMTool for planning the global driving controller for high efficiency AGV. We acquire the control efficiency by controlling the motor used each part of AGV driving controller. The block diagram structures provided with SIMTool is easily designed by the controller, and the monitoring and analysis of the results is researched by simulation. We expect to control AGV. robot and various plant using Ziegler-Nichols auto-tuning method and external I/O board

• 한국분무공학회지
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• 제16권2호
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• pp.97-103
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• 2011

The electronically controlled diesel engine was converted to dual fuel engine system. Test engine was set up for investigating the power output, thermal efficiency and emissions. ND 13-mode tests were employed for the engine test cycle. The emission result of dual fuel mode meets Euro-4 (K2006) regulation and the engine performance of dual fuel engine was comparable to the performance of diesel engine. To estimate economical efficiency, test vehicles have been operated on a certain driving route repeatedly. Fuel economy, maximum driving distance per refueling and driveability were examined on the road including free ways. Developed vehicle can be operated over 500 km with dual fuel mode and shows 80% of diesel substitution ratio. Driveability of dual fuel mode is similar with that of diesel mode.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.83-84
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• 2015

In order to use the high-speed range of Interior Permanent Magnet Synchronous Motor(same as IPMSM above), the motor should be at flux weakening control status. High-speed range is called field weakening control region or constant power region, and explain the basic theory of flux weakening control used in the constant power region. Back electromotive force of IPMSM is measured. and field weakening conrtrol driving characteristics is configurated verification test. Through experimentation speed-torque characteristic curve, the efficiency variation corresponding to the current phase angl,the efficiency map were produced.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.33-37
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• 2002

This paper presents a simple torque estimation method and the switching angle control of SRM using Neural Network. SRM has gaining much interest as industrial applications due to the simple structure and high efficiency. Adaptive switching angle control is essential for the optimal driving of a SRM because of the driving characteristic varies with the load and speed. The proper switching angle which can increase the efficiency was investigated in this paper Neural Network was adapted to regulate the switching angle and nonlinear inductance modelling. Experimental result shows the validity of the switching angle controller.

• 전력전자학회논문지
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• 제8권5호
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• pp.450-454
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• 2003

이 논문에서는 단상 SRM의 새로운 구동 설계를 제안한다. 이 구동 설계는 매우 간단하고 저가이다. 이 설계는 간단한 전력 장치를 사용함으로 적은 스위칭 손실로 높은 효율의 SRM 구동을 가능하게 한다. 초기 구동시, 단상 SRM에서의 중요한 문제를 하나의 홀센서와 자석, 새로운 초기 구동 알고리즘에 의해 극복했다. 제안된 단상 SRM은 일반적인 모터의 것과 비교하여 고효율과 확실한 구동 특성을 가지고 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.164-166
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• 2002

HVT(High Voltage Transformer) has been used to drive a magnetron in a microwave oven. This has some problems which are heavy weight, low efficiency and limit of output. To overcome these problems, this paper proposes a boost input type active clamp AC-DC converter for magnetron driving featuring the high efficiency and improved EMI characteristics. To verify the validity of the proposed converter operation, the prototype converter of 700W was built and tested.