• 한국측량학회지
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• 제14권1호
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• pp.89-95
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• 1996

항공사진측량 분야에 대한 GPS 기술 응용의 한 예로, 수신기를 항공기에 탑재하여 카메라의 위치를 정확히 측정함으로써 기존의 항공사진측량에서 필요했던 많은 지상기준점을 항공기준점(aerial control points)으로 대체하려는 이론적 연구를 수행했다. 본 연구에서는 GPS 데이타를 항공사진측량에 이용하기 위해 여러 가지 경우에 대해서 Simulation을 통해 항공사진측량에서 대상점의 위치결정에 영향을 주는 조건들을 규명하고, 이에 따라 1:1,000 지형도 작성을 위해 필요한 조건들과 실제의 적용을 위한 값을 제시하였다. 본 연구의 결과는 104매의 사진 블럭에서 지상측량을 포함하고, $10\mu{m}$ 이상의 정밀도로 좌표측정을 하였을 경우에 6점의 지상기준점 만으로도 충분한 정도의 결과를 얻을 수 있음을 보임으로써 이 기술의 실제적용이 이론적으로 가능함을 입증하였다.

• 한국기계가공학회지
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• 제14권1호
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• pp.63-69
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• 2015

Recently, research and interests in pilotless and radio-controlled quadcopters have increased due to military, hobby, and air-photo applications. However, quadcopters are fragile and can very easily to break when they crash. Therefore, it is necessary to create a protective device such that these devices can protect the main board, motor, and propellers from outside impacts. In this paper, a protective device for a quadcopter is designed in the form of a circle to disperse shock. Also, a dropping and impact simulation was performed to verify that the quadcopter can be efficiently protected when using the proposed device, created with the commercial finite element software Solidworks.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2006년도 학술대회 2부
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• pp.613-618
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• 2006

테마파크는 현대 사회와 복잡함 속에서의 현실 탈피와 참여로써 자기 성취를 구현하는 현대적 개념의 종합위락시설로 모든 계층의 사람들이 즐길 수 있는 창조적 유희공원의 일반적 특징을 갖고 있다. 테마파크를 공간, 주제, 유형에 의해 분류해 볼 때 산업적 성공 가능성이 많은 것으로는 공간-실내, 주제-캐릭터, 유형-쇼핑으로 현재 일본의 산리오 퓨로랜드나 국내 일산의 헤이리 딸기파크가 그 사례이다. 본 연구에서는 실내캐릭터쇼핑파크의 사용자 분석을 통하여 온 오프라인 체험 컨텐츠의 가능성을 발견하고, 이를 VR 시뮬레이션 시나리오로 제안하였다. 방법으로는 헤이리 딸기파크에서 5 그룹, 9 개 구역을 필드리서치 하여 체험 시나리오 개발을 위한 의미 있는 단서를 발견하였으며, 이를 토대로 시나리오 기법을 활용하여 7 구역 14 개 시안을 도출하였다. 최종 구체적 사례로 포토포인트 시나리오를 설정하여 오프라인 연계 VR 시나리오를 이용한 구축 사례를 통해 제시하였다. 컨텐츠 개발의 제안을 중심으로 연구 범위를 디자인 사례의 제안으로 제한하였으며, 이는 향후 온 오프라인 연계 테마파크의 구체적 컨텐츠 개발의 활용을 목적으로 디자인되었고, 공간의 실제적 검증을 위한 Web-VR 시뮬레이션 기법의 검토에 도움을 줄 것으로 판단된다.

• 조명전기설비학회논문지
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• 제23권5호
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• pp.72-79
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• 2009

태양 에너지는 재생 가능하고 오염이 없는 특성으로 바람직한 에너지 원이다. 계통에 이용하기 위해서는 dc-dc 컨버터와 계통 연계 do-ac 인버터가 필요하다. dc-dc 컨버터는 태양광 시스템이 높은 dc전압에 동작하기 위하여 필요하고, 인버터는 계통에 연결하기 위하여 필요한 전압과 주파수를 만들어 내는데 필요하다. 본 논문에서는 첫째로 단상 계통 연계 인버터에서 전류 루프 전달 함수가 유도되고, 둘째로 컨버터 측에서 컨덕턴스 증가 방식의 MPPT 방식이 제안하여 인버터 측에 최대 전력을 공급하는데 있다. 시뮬레이션 결과가 계통에서 태양광 인버터 시스템의 성능과 특성을 보여준다.

• 한국생산제조학회지
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• 제19권6호
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• pp.834-840
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• 2010

Photo lithography process is very important technology to fabricate highly integrated micro patterns with high precision for semiconductor and display industries. Up to now, mask type lithography process has been generally used for this purpose; however, it is not efficient for small quantity and/or frequently changing products. Therefore, in order to obtain higher productivity and lower manufacturing cost, the mask type lithography process should be replaced. In this study, a maskless lithography system using the DMD(Digital Micromirror Device) is developed, and the exposure condition and optical properties are analyzed and simulated for a single beam case. From the proposed experimental conditions, required exposure experiments were preformed, and the results were investigated. As a results, 10${\mu}m$ spots can be generated at optimal focal length.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.303-304
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• 1998

We investigated the effects of scintillation crystal surface treatment on gamma camera imaging. The NaI(Tl) and CsI(Tl) (20 mm (dia.) $\times10mm$ (thick) plate) scintillators were chosen for this study. Two different surface treatments, white and black reflectors, were applied to NaI(Tl) and CsI(Tl). The optical properties of generated scintillation light were evaluated using Monte Carlo simulation and postion sensitive photo multiplier tube (PSPMT). We measured sensitivity, energy resolution and spatial resolution of a gamma camera system with the scintillators coupled to a PSPMT. Based on the results, we concluded that the careful consideration of surface treatments of the scintillator was necessary in order to develop the gamma camera having good sensitivity and spatial resolution.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2004년도 정기학술대회
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• pp.147-151
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• 2004

In this study, an optical fiber assembly directly coupled with a laser diode or a photo diode is designed to confirm high reliable optical coupling efficiency of optical transmitter(Tx) and receiver(Rx). The optical fiber assembly is fabricated by soldering an optical fiber and a Kovar ferrule using a glass solder after inserting an optical fiber through a Kovar ferrule. The Kovar which has good welding characteristics is applied to introduce laser welding technique. The glass solder has excellent thermal characteristics such as thermal shift delamination compared with PbSn, AuSn solder previously used usually. Furthermore, the glass solder doesn't need fiber metalization and this enables low cost fabrication. However, the glass soldering is high temperature process over 35$0^{\circ}C$ and the convex shape after solidification due to surface tension causes the stress concentration on optical fiber. The stress concentration on the optical fiber increases the optical insertion loss and possibility of crack formation. The shape of glass solder was designed referring to 2-D Axi-symmetric FEM simulation. To test the mechanical reliability, mechanical vibration test and shock test were done according to Telcorida GR-468-Core protocol. After each test, the optical loss of the stress distributed fiber assembly didn't exceed 0.5 dB, which passes the test.

• 정보저장시스템학회:학술대회논문집
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• 정보저장시스템학회 2005년도 추계학술대회 논문집
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• pp.32-37
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• 2005

We developed a numerical simulator in order to study the Super-RENS/ROM (Super REsolution Near-Field Structure, Read Only Memory) using 3-dimensional FDTD (finite difference time domain) method. The simulation can be performed by three steps. In the first step, we utilized the vector-diffraction theory to calculate the characteristics of incident laser beam from the object-lens to the surface of the disk. At the second step, we fed the calculated result as an input for the main FDTD simulations on the optical layers in the disk structure. After performed the FDTD simulations, we took near-to-far field transformation for the reflected signal, from the surface of the disk to the detector. Finally, we can get reflected signal at the photo-diode. Using this developed simulator, we were able to study about the reading signal from various disk structures as a function of a laser beam position. We calculated reading signals for various pit sizes for Super-ROM structure, and it is found that the simple optical diffraction theory can not explain the reading mechanism of Super-ROM, and more complicated temperature dependent physics must be involved.

• Journal of the Optical Society of Korea
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• 제15권2호
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• pp.132-139
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• 2011

We investigate theoretically the combined effect of fiber chromatic dispersion and self-phase modulation (SPM) on multi-channel subcarrier multiplexed (SCM) optical transmission systems in terms of the detected RF carrier power and SPM-induced power gain after transmission over single-mode fiber (SMF) links. According to the calculated power gain due to the SPM effect at the transmission distance of P3dB using the detected radio-frequency (RF) carrier power after photo-detection, the power gain is significantly degraded with large optical modulation index (OMI), small SCM channel spacing, and large fiber launching power because of the increased interaction between subcarrier channels. The nonlinear phase shift due to linear and nonlinear fiber characteristics is investigated to explain these results in detail. The numerical simulation results show that the OMI per SCM channel has to be smaller than 10 % for the fiber launching power of 10 dBm to guarantee prevention of SPM-induced power gain degradation below 0.5 dB for the SCM system with the channel spacing of 100 MHz. This result is expected to be utilized for the optical transmission systems using the SCM technology in future radio-over-fiber (RoF) networks.

• 한국CDE학회논문집
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• 제19권3호
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• pp.253-262
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• 2014

3D city model, which consisted of the 3D building models and their geospatial position and orientation, is becoming a valuable resource in virtual reality, navigation systems, civil engineering, etc. The purpose of this research is to propose the new framework to generate the 3D city model that satisfies visual and physical requirements in ground oriented simulation system. At the same time, the framework should meet the demand of the automatic creation and cost-effectiveness, which facilitates the usability of the proposed approach. To do that, I suggest the framework that leverages the mobile mapping system which automatically gathers high resolution images and supplement sensor information like position and direction of the image. And to resolve the problem from the sensor noise and a large number of the occlusions, the fusion of digital map data will be used. This paper describes the overall framework with major process and the recommended or demanded techniques for each processing step.