• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.1011-1015
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• 2005

Fully digital controlled 20-bit magnet power supplies have been developed and successfully tested for closed orbit correction of PLS(Pohang Light Source). The new digital power supply has used fiber optics for 25kHz switching of IGBT drivers, and implemented DSP, ADC, Interlock, DCCT cards in a compact 3U-sized 19" chassis. Input/Output low-pass filters suppress harmonics of 60Hz line frequency and switching frequency noise effectively. Overall performance of the power supplies have been demonstrated as +/- 2ppm short-term stability(<1 min), and +/- 10ppm long-term stability(<36 hours). All the existing 12-bit 70 power supplies for vertical correction magnets will be replaced with new digital power supplies during 2005 summer shutdown period. In this paper, we will describe the hardware structure and control method of the digital power supply and the experimental results will be shown.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.2030-2032
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• 1998

It is always necessary to high performance power supplies for the magnet system in the accelerator, especially when the number of power supplies are large. When have developed the compact power supply using switching technology instead of SCR phase control. We adopt the pulse width modulation(PWM) method with a half bridge DC/DC converter. In this way, we can make a compact system with light weight and small volume. Actual system we developed is 1.2kW, 35V/35A bipolar DC power supply current precision of +/-0.02%. It is possible to mount 10 unit in a conventional 19 rack. The built in controller has an RS422 protocol to drive 10 unit by one serial port up to 1.2km distance. If we adopt RS485 protocol, one serial port can control 32 power supplies. In this paper, we will report the design and performance of the prototype power supply.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1683-1688
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• 2008

These days, in Korea, according to improving the standard living, people generally work 5 days a week and it results more leisure hours. On weekends or in specific season, travel to mountain region around the major city is much in demand, and, in case of public transportation, the demand exceeds the supply. So, people tend to go other places, even overseas, for their holidays. The situation in Korea reflects the needs for mountainous light rail transit system with the object of convenient and rapid transport of passengers. In this paper, the guideline for mountainous light rail transit planing is proposed, and the representative mountainous light rail transit system is analyzed to choose the proper mountainous light rail transit system which adapts the demand for transportation and the terrain in Korea.

• 한국전기전자재료학회논문지
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• 제29권4호
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• pp.237-240
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• 2016

The improvement of irradiation intensity and irradiation uniformity is essential for large area and high power UVA light source application. In this study, large number of chips bonded by micro soldering technique were driven by low current, and current limiting diodes were configured to supply constant current to parallel circuits consisting of large number of series strings. The dimension of light source module circuit board was $350{\times}90mm^2$ and 16,650 numbers of 385 nm flip chip LEDs were used with a configuration of 90 parallel and 185 series strings. The space between LEDs in parallel and series strings were maintained at 1.9 mm and 1.0 mm distance, respectively. The size of the flip chip was $750{\times}750{\mu}m^2$ were used with contact pads of $260{\times}669{\mu}m^2$ size, and SAC (96.5 Sn/3.0 Ag/0.5 Cu) solder was used for flip chip bonding. The fabricated light source module with 7.5 m A supply current showed temperature rise of $66^{\circ}C$, whereas irradiation was measured to be $300mW/cm^2$. Inaddition, 0.23% variation of the constant current in each series string was demonstrated.

• Journal of the Korean Data and Information Science Society
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• 제22권4호
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• pp.735-740
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• 2011

최근 전자기기의 소형화, 인텔리전트화, 다기능화, 광대역화에 관심이 집중되어 많은 발전이 이루어졌으며, 이들 전자기기들에 이용되는 모듈형의 전원장치 (SMPS : Switching-mode power supply)도 소형화, 경량화, 고효율화, 고신뢰성화, 저노이즈화를 실현하고 있다. 85~265 볼트교류전압(VAC : Voltage alternating current) 상용 전원을 공급받아 DC 출력을 공급하는 전원장치인 파워모듈은 마이크로컨트롤러, 릴레이 등 전기, 전자 회로용 전원 공급기를 간단하고 쉽게 설계하도록 개발되고 있다. 이 모듈은 전원을 사용하는 장비에 광범위하게 적용할 수 있어 에너지 절감이라는 세계적인 대과제에 적합한 제품이기는 하나 제품의 품질과 성능에 대한 통계적분석이 필요한 바 적용제품의 부하별, 출력전압별 성능분석을 하여 그 문제점을 찾아보려고 한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1657-1659
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• 2005

Test track of the Light Rail Transit(LRT system was developed and organically combined with technologies of power supply system, signal communication system and track structure The purpose of the test track is a acquiring of reliability and stability through a sufficient performance test Therefore, this paper draws up ail management plans for tests of the LRT system

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.915-923
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• 2011

Our country is promoting the introduction of new means of transportation due to insufficient supply according to the existing demand of road traffic. Among them, manless light railroad transit is settled down as the most definite alternative. However, new traffic systems such as manless light railroad have certain difference between characteristics of hardware and software and subway system. Therefore, there will be many differences compared to the existing contingency system when accidents occur. Railway management organization has to establish railway contingency plan and acquire permission from the minister of the Ministry of Land, Transport, and Maritime Affairs. However, as commercial transportation is available, a new traffic system also should establish contingency plan. Therefore, the establishment of systematic contingency plan is suggested in order to analyze characteristics of manless light railroad in the beginning of introduction and to make contingency response available.

• 한국안전학회지
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• 제28권2호
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• pp.31-36
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• 2013

For lighting of dark and hazardous workplace such as compartment of ships under construction, workers should use hand lamps of explosion-proof type. However, the heavy weight of such lamps has prevented most impatient workers from using such types of lamps extensively. In this paper, we developed a light weight hand lamp of intrinsic safety type which reduced the weight a lot while maintaining or improving the lighting and explosion-proof function. We made a prototype which consisted of lamp fixture and high frequency power supply. Testing results show that the hand lamp meets well all the explosion-proof testing requirements of the Korea Occupational Safety and Health Agency. And more, we surveyed the explosion protection technology of a light weight hand lamp, and suggested the advantage/disadvantage to apply lighting of hand lamp about economical aspect.

• Journal of Biosystems Engineering
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• 제35권3호
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• pp.197-205
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• 2010

An automatic echelon feeder of brown rice was presented for quality inspection system using color image processing. A echelon feeder was developed with vibratory feeder and cylindrical indent singulator having oblique light. The vibratory feeder consisted of a hopper, electromagnetic vibrator and multichannel grooves and supply the grain sample to the singulator. The feeding performance such as feed rate, blocking frequency of the channel was dependent on the size of groove and vibration pattern. A cylindrical indent singulator consisted of a rotating cylinder, prisms and a tungsten-halogen light source. It delivered grain kernels under the camera in a echelon form and illuminate the kernels with oblique ray and ambient light. The size of the indents installed on the surface of the rotating cylinder was determined by the dimensions of the paddy and a small triangular prism was placed in each indent to apply $ 20^{\circ}$ oblique light to the grain kernel.

• 센서학회지
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• 제25권5호
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• pp.337-343
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• 2016

In this paper, we newly introduce a wireless identification system using a solar cell and RF transceivers. The reader sends interrogating signal to a transponder using LED visible light, and the transponder responds to the reader using RF signal. The transponder consists of a solar cell, an amplifier, a microprocessor, and an RF transmitter. The solar cell receives the visible light from the reader and generates current to supply electric power to the other devices in the transponder. At the same time, the solar cell detects interrogating signal in the reader light. The microprocessor senses the interrogating signal and generates a responding signal. The RF transmitter radiates the responding signal to the reader. The transponder is a passive circuit because it operates without external power. In experiments, the maximum read distance between a reader and a transponder was about 1.6 meter.