• 정보저장시스템학회논문집
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• 제2권2호
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• pp.100-104
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• 2006

Stamper surface temperature is very critical in replicating the high density optical disc substrates using injection molding as the pit or land/groove patterns on the optical disc substrate have decreased due to the rapid increase of areal density. During the filling stage, the polymer melt in the vicinity of the stamper surfaces rapidly solidifies and the solidified layer generated during polymer filling greatly deteriorates transcribability and fluidity of polymer melt. To improve transcribability and fluidity of polymer melt, stamper surface temperature should be controlled such that the growth of the solidified layer is delayed during the filling stage. In this study, the effect of heating on replication process was simulated numerically. Then, an injection mold equipped with instant active heating system was designed and constructed to raise the stamper surface temperature over the glass transition temperature during filling stage of the injection molding. Also, the closed loop controller using the Kalman filter and the linear quadratic Gaussian regulator was designed. As a result. the stamper surface temperature was controlled according to the desired reference stamper surface temperature.

• 한국광학회지
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• 제16권4호
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• pp.376-383
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• 2005

[ $Ti:LiNbO_3$ ] 채널 광도파로와 전기광학효과를 이용하여 설계된 집적광학 파장가변 편광모드 조절기를 설계 및 제작하고, 동작특성을 측정하였다. 소자는 $TE↔TM$ 모드변환기와 TE./TM 위상변환기로 구성되었으며, Jones 매트릭스를 이용하여 각각의 전달 매트릭스를 유도하였다. 위상변환기에 의한 파장 변환율을 전산 모사하였으며, 제작된 소자의 동작 특성들을 확인하였다. 폴래리미터와 Poincare 구 좌표계를 이용하여 편광 조절기의 동작 상태를 체계적으로 측정하였다.

• 항공우주기술
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• 제9권2호
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• pp.161-167
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• 2010

지구관측을 위한 광학위성에 탑재되는 고해상도 영상 획득을 목적으로 하는 위성카메라의 카메라전자부(CEU : Camera Electronic Unit)는 CC(Camera Controller)와 FPA(Focal Plane Assembly), CEUP(CEU Power supply)로 구성된다. 본 논문은 광학위성 탑재체(CEU)의 전자파시험결과와 이를 토대로 한 시스템 양립성 검토결과를 설명하였다. CEU의 1차 전자파시험은 전도성 방출시험, 전도성 감응시험, 복사성 방출시험 및 복사성 감응시험을 수행하였고 2차 시험에서는 1차 시험에서 규격을 만족하지 못함으로서 시스템 성능에 중요한 영향을 미칠 수 있는 복사성 방출시험과 복사성 감응시험을 차폐제를 이용하여 기구적인 차폐를 보강 후 수행하였다. 2차 시험결과에 대한 시스템 양립성은 탑재체(CEU)에서 방출하는 노이즈의 주파수성분이 위성의 GPS/S-Band 수신 성능에 미치는 영향성을 분석하였다. 기구적인 차폐보강이 전제되었을 때, 두 수신대역 내에서 발생하고 있는 노이즈 주파수성분에 대하여 6dB 이상의 마진을 갖는 것으로 나타났다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권2호
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• pp.98-104
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• 2003

This paper proposes the design of a multi-color lamp using high brightness RGB LEDs for color variation. Appropriate number of RGB LEDs is so chosen according to the color mixing theory that the overall LEDs represent a color temperature of 6500K. Also, the chosen RGB LEDs are suitably arranged by using an optical design program. The lamp has an internal controller circuit, so it can be directly connected to the existing incandescent lamp socket. It's main body is comprised of two PCB layers. The upper layer contains 44 LEDs and the lower one has a simple microcontroller-based PWM control circuit. The lamp has functions of both ON/OFF control and PWM control, and enables color variation of over 100,000 colors and of more than 10 patterns.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.190-198
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• 2002

In switched reluctance motor(SRM) drive, it is necessary to synchronize the stator phase excitation with the rotor position. Therefore the rotor position information is an essential. Usually optical encoders or resolvers are used to provide the rotor position information. These sensors are expensive and are not suitable for high speed operation. In general, the accuracy of the switching angles is dependent upon the resolution of the encoder and the sampling period of the microprocessor. But the region of high speed, switching angles are fluctuated back and forth from the preset values, witch are cause by the sampling period of the microprocessor. Therefore, the low cost linear encoder suitable for the practical and stable SRM drive is proposed and the control algorithm to provide the switching signals using the simple digital logic circuit is also presented in this paper It is verified from the experiments that the proposed encoder and logic controller can be a powerful candidate for the practical low cost SRM drive.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.16-18
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• 2003

In a switched reluctance motor drive, it is important to synchronize the stator phase excitation with the rotor position, because the position of rotor is an essential information. In the high-speed region, switching angles are fluctuated back and forth out of the preset value, which is caused by the sampling period of the microprocessor. In this paper, a low cost analog encoder suitable for practical applications is proposed. The validity of the proposed analog encoder with a proper logic controller is verified from the experiments.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.1004-1009
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• 2002

There are four servo systems in a DVD drive such as a focus servo system, a tracking servo system, a sled servo system and a spindle servo system. Focus servo system maintains relative distance between lens and disk. In this paper, two plant models for the focus servo system will be presented. One of them is conventional and the other is newly developed. Focus error signal between lens and disk is detected using LDV 2 beam method. The system is observable and all states are estimated. Full states feedback controller and minimum order observed are designed using those states. Impulse responses are simulated. And experiment is performed to compare with responses of conventional model.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2009년도 춘계 종합학술대회 논문집
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• pp.70-73
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• 2009

Wii의 기본 컨트롤러인 위 리모트(Wii Remote)는 모션센서(Motion Sensor)를 내장하고 있어 컨트롤러 사용자의 움직임을 3차원 좌표로 인식한다. 또한, 블루투스(Bluetooth)를 통해 컨트롤러의 확장이 가능하여 PC에서 마우스처럼 다른 응용프로그램을 제어하는데 사용할 수 있다. 본 연구에서는 모션센서와 블루투스 기능을 이용하여 위 리모트를 쥐고 있는 사용자가 화면에 가르키고 있는 좌표 값에 대한 정보를 받아 화면에 나타내는 드로잉을 구현하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.851-854
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• 2004

This paper studies Optical Fiber(OF) - LED illuminated display board system for energy saving. The OF-LED illuminated display board system has PV modules, batteries, and charge & discharge system, and dynamic full color display controller. Both maximum power point tracker (MPPT) and constant current & constant current controls (CCVC) are used In govern the charging system. It can be improve the charging efficiency of battery. The objective of this thesis paper is to build advertisement lighting system with OF-LED in to charge a 12-volts lead acid battery by using a field wired PV array. We saved the maintenance cost and developed of advertisement effectiveness. To verify the proposed OF-LED illuminated display board system for energy saving, the detail simulation and experiment results indicate that operating characteristics are verified by experiment with a laboratory prototype in this paper.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 B
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• pp.652-654
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• 1999

This paper presents approaches to the control of the DVD(Digital Video Disk) system using DSP(Digital Signal Processor) in order to improve the precision and robustness. To improve the performance of the Pick-Up servo actuator of the digital video drive, the tracking and focusing servo control algorithms is applied to this system. Simulation results show the performance of the robust control algorithm applied the pick-up servo system comparing to the linear controller.