• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.309-310
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• 2019

현재 화석연료 고갈과 미세 먼지 등의 환경 문제는 전 세계적인 이슈가 되어가고 있으며, 이에 따라 태양광, 풍력 등 신재생 에너지 사용 및 설치가 늘어나고 있다. 반면에, 다양한 분산 전원의 증가로 인해, 계통 불안정 문제 역시 전면에 대두되고 있으며, ESS등 계통 보조 시스템에 대한 관심과 실제 설치는 점점 선택이 아닌 필수적 조건으로 자리잡고 있다. 시장의 확대에 따라, 해당 시스템의 신뢰성과 효율에 대한 관심 역시 증가되고 있으며, 최대한의 성능을 위해 태양광 및 ESS등의 전압은 LV(Low Voltage)의 한계점인 1500V를 달성하였고, 이에 따라 ESS와 PCS역시 해당 전압에서의 동작 및 효율적인 동작 및 설치를 위해 발전하고 있다. 본 논문에서는 이러한 상황에 맞춰 효율적인 PCS 개발을 위한 방안을 제안하도록 한다.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.8
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• pp.195-201
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• 2014

In this paper, we developed a LGP(Light Guide Panel) dry cleaning system for particle cleaning using corona discharge and dry adhesive roll. Therefore, we design a cleaning mechanism that can be applied dry adhesive dust removal roll and ESD(electrostatic discharge) by using corona discharge. Also, we design and implementation of equipment, which can loading, unloading and transfer LGP automatically. The developed equipment is dust and particle cleaning experimental results to demonstrate its stability.

• Journal of KIISE:Software and Applications
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• v.26 no.2
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• pp.223-233
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• 1999

데이터베이스 공유 시스템(Database Sharing System : DSS) 은 고성능의 트랜잭션 처리를 위해 제안된 구조이다. DSS에서 고속의 통신망으로 연결된 노드들은 별도의 메모리와 운영체제, 그리고 DBMS를 가지며, 데이터베이스르 저장하고 있는 디스크는 모든 노드에 의해 공유된다. 빈번한 디스크 액세스를 피하기 위해 각 노드는 자신의 메모리 버퍼에 최근에 액세스한 페이지들을 캐싱한다. 본 논문에서는 레코드와 같은 미세 단위의 로킹을 지원하는 DSS에서 데이터베이스를 정확한 상태로 복구할 수 있는 회복 기법인 DRCP(Database Recovery using Cached Pages)를 제안한다. DRCP는 정상적으로 동작하고 있는 다른 노드에 캐싱된 페이지의 내용을 참조하여 회복 작업을 수행함으로써 디스크 액세스 수와 회복 과정에서 필요한 로그 스캔의 범위를 줄일 수 있고 , 그 결과 데이터베이스를 빨라 복구할 수 있다는 장점을 갖는다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.4
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• pp.419-424
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• 2009

A Xenon feed system has been developed for a 300 W Hall-effect thruster intended for orbit maintenance of small satellite. The system can store about 2 kg of xenon gas at 150 bar and is capable of controlling the mass flow rate of the gas at 0.5 SCCM resolution. The performance of the system is verified with a laboratory experiment. It is confirmed that the operation of the feed system is successful at a pressure level of $1.0{\times}10^{-6}$ torr in the vacuum chamber.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.4
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• pp.305-310
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• 2014

In this study, a non-destructive evaluation (NDE) mothod is proposed for ball bearings contaminated with micro foreign substances, which were inserted into a ball bearing to create a defective specimen. The non-contact quantitative infrared thermographic technique was applied for NDE condition monitoring. Passive thermographic experiments were conducted to perform early fault diagnosis, for bearings operated at optimized torque status under a dynamic load condition. The temperature profiles for normal and defective specimens were quantitatively compared, and the thermographic data analyzed. Based on the NDE results, the temperature characteristics and abnormal fault detection of the ball bearing were quantitatively analyzed according to the rise in temperature.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12C
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• pp.255-260
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• 2001

This paper describes the design of the Register Controlled DLL(Delay-Locked Loop) that achieves fast locking and low Power consumption using a new locking algorithm. A fashion for a fast locking speed is that controls the two controller in sequence. The up/down signal due to clock skew between a internal and a external clock in phase detector, first adjusts a large phase difference in coarse controller and then adjusts a small phase difference in fine controller. A way for a low power consumption is that only operates one controller at once. Moreover the proposed DLL shows better jitter performance Because using the lock indicator circuit. The proposed DLL circuit is operated from 50MHz to 200MHz by SPICE simulation. The estimated power dissipation is 15mA at 200MHz in 3.3V operation. The locking time is within 7 cycle at all of operating frequency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.344-346
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• 2018

Air pollution has become a social issue. Particularly, interest in fine dust is increasing. Various kinds of sensors are being used to measure fine dust. The most commonly used infrared detection dust sensors operate by sensing the diffraction of light through an infrared receiver and sensing the light reflected by the dust in the air. However, this method has a drawback in which accurate data analysis is difficult due to deviation caused by the noise during measurement. In order to overcome such drawbacks, in this thesis, a low pass filter algorithm of FIR(Finite Impulse Response) filter was designed and implemented.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.42-53
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• 1993

이 논문에서는 정밀로봇 설계에 관한 여려 사안을 다루었다. 정밀로봇이란 미세한 오차와 정밀한 제어로 기존 로봇의 정밀도 향상을 위한 작고, 정밀한 운동범위를 갖춘 로봇이다. 원하는 운동범위나 효과적인 힘 전달률, 최소한 작은 힘으로의 동작을 수행하기 위한 최적의 기구학적 변수를 컴퓨터 시뮬레이션을 통하여 구현하고자 한다. CAD/CAM 시스템을 이용한 합성, 해석 및 제작을 위한 정보가 만들어질 수 있으며 최대 휨 및 응력해석을 통하여 최종적인 검증 및 설계 변경을 위한 자료로서 사용될 수 있을 것이다.

• The Korean Journal of Ecology
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• v.23 no.3
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• pp.273-279
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• 2000

This study was conducted to clarify the characteristics of bird community in Han River area from Oct. 1997 to Jul. 1998. Total 107 bird species were recorded in Han River area. Bird mainly distributed around Kangdong Bridge, Paldang Dam, Yangsuri, Haengju Bridge, Sungsan Bridge, and Bam island. The area between Dongiak Bridge and Youngdong Bridge showed the lowest the density of birds. The dominant birds of Han River area were the dabbling ducks, which were Anas platyrhynchos and A. poecilorhyncha. Diving ducks were distributed in the Dongiak Bridge, Youngdong Bridge, and estuary area. Grebes, Gulls, Herons, and Coots were also dominant bird species. Cormorants, Swans, Sandpipers, and Plovers were minor birds in Han River area. Maintenance and management of various micro-habitats are needed for habitation of bird community in Han River area.

• Journal of KIISE
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• v.44 no.10
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• pp.1094-1104
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• 2017

In this paper, a motion image is detected based on the irregularity of lights. This motion image is extracted by modifying the reflected light region of the 3 way-diff algorithms. 3 way-diff algorithm extracts reflected light region using the 3-successive image. In this algorithm, The reflected light region is a region generated by light in the image production process and is finally created around all objects. The algorithm shows a process to extracting the region. This process is a simple operation, but doesn't have a defined formula for light. This paper judges that the reflected light region is a kind of noise at the 3 way-diff algorithms and defines the formula for extracting the reflected light region. It shows that compared with the proposed algorithm and existing algorithm through experiment.