• 융합정보논문지
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• 제10권2호
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• pp.96-101
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• 2020

반도체 조명과 아울러 디스플레이의 주요한 광원으로서 주목받고 있는 마이크로 크기의 발광다이오드에서 광학적 특성 및 효율의 향상을 위해 다양한 개발 방향과 연구 방법이 제시되어져 왔다. 하지만 이러한 개발 방향과 방법은 2차원 구조를 기반으로 하고 있으며, 이에 따라 연구와 개발이 진행되어왔다. 본 연구에서는 기존의 평면구조와는 구별되는 나노 프레임 구조를 통한 입체적인 나노 구조의 설계와 아울러 미세 패턴과 반응성 에칭 방법이 적용된 반도체 공정 적용을 제시하고자 한다. 또한, 나노 프레임 구조의 구현을 위해 적용된 공정 개발을 통해 수직성이 향상된 나노 캐비티와 이를 통한 나노 기둥의 제시를 통해 나노 구조의 반도체 광원으로의 적용 가능성을 제시하고자 한다.

• 한국자동차공학회논문집
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• 제18권6호
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• pp.114-121
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• 2010

This paper presents a design process of light-weighted fuel cell vehicle (FCV) frame to meet design target of natural frequency in early design stage. At first, using validated FE model for the current design, thickness optimization was carried out. Next. optimization process, comprised of beam model size optimization, shell model design and shell model thickness optimization, was investigated for two frame types. In addition, in order to ensure hydrogen tanks safety against rear impact load, structural collapse characteristics was estimated for the rear frame model finally produced from the previous optimization process and, with the target of equal collapse characteristics to the current design model, structural modification with small weight increase was studied through static structural collapse analyses. The same attempt was applied to the front side frame. The results explain that the proposed process enables to design light-weighted frames with high structural performance in early stage.

• 한국철도학회논문집
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• 제5권4호
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• pp.222-230
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• 2002

The rotating bogie frame is used in the bogie for a Light Rail Train under development in Korea. In development of the bogie, the structural strength and fatigue characteristics of the rotating bogie frame have been evaluated under the predefined load cases according to the Korean standards for a urban EMU. No part of the rotating bogie frame was subjected to stress beyond the fatigue endurance limits of the material used when grinding the welding of the lower plate link. It is concluded that the rotating bogie frame is safe in view of its static and fatigure strength.

• Journal of Information Display
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• 제10권2호
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• pp.49-53
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• 2009

In this study, a very small LED packaging lead frame with a low thermal resistance was developed. The cost of the package process was reduced by the use of many small LED lamps, which increased the light emission efficiency. Compared to the large lead frame lamp, however, the optical property of the small LED packaging lead frame lamp was not sufficiently improved because its reflection structure was changed and its reflection area was reduced. The luminous efficiency of the LED lamp reaches 58 lm/W at the current density of 0.16 A/$cm^2$. Using the LED lamps, 46-inch LCD BLU was manufactured. The BLU-made LED lamps have a low power consumption of 146 W and have a slim (10-mm-thick) BLU, keeping good uniformity in terms of brightness, and maintaining good thermal properties.

• 복식
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• 제64권7호
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• pp.82-96
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• 2014

This study views the shadows cast by the light and a subject provides new interpretations rather than it simply being an additive product. Particularly in fashion photograph, light and shadows are often used as tools to convey meaning. Accordingly, this study aims to classify the utilization of the shadow created by light and deriving its expressive characteristics in fashion photograph. To achieve these research aims, literature and case studies were conducted. The results are as follows. First, the shadows were mainly focused on a subject. Secondly, shadows caused by lighting is casted directly into the inside of the main subject in a frame takes a role of omission or emphasis. Third, shadows caused by a second unseen object outside the frame are utilized with the main subject in the frame. Based on these results above, spatial third dimensionality, optical illusion and accentuation were derived as expressive characteristics of the shadow in fashion photograph. As such, in fashion photograph, shadow is an important element for photographers. The variability of the shadow makes it possible for creative changes as its amount, angle and direction can be altered by adjusting the light in accordance with the intention of the artist. Therefore, its utilization methods will be diversified hereafter. Accordingly, it is required to recognize that shadow may be recreated as an independent object in fashion photograph.

• Journal of Electrical Engineering and Technology
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• 제11권2호
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• pp.508-518
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• 2016

In this paper, we propose a method combining an accelerometer with a cross structured light system to estimate the golf green slope. The cross-line laser provides two laser planes whose functions are computed with respect to the camera coordinate frame using a least square optimization. By capturing the projections of the cross-line laser on the golf slope in a static pose using a camera, two 3D curves’ functions are approximated as high order polynomials corresponding to the camera coordinate frame. Curves’ functions are then expressed in the world coordinate frame utilizing a rotation matrix that is estimated based on the accelerometer’s output. The curves provide some important information of the green such as the height and the slope’s angle. The curves estimation accuracy is verified via some experiments which use OptiTrack camera system as a ground-truth reference.

• 한국자동차공학회논문집
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• 제20권3호
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• pp.77-82
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• 2012

It is well known that the targeted fuel efficiency could only be achieved by more than 40% reduction of the vehicle weight through improved design and extensive utilization of lightweight materials. In order to obtain the goal of the weight reduction of automobiles, the researches about lighter and stronger rear sub-frame have been studied without sacrificing the safety of rear sub-frame. In this study, the weight reduction design process of rear sub-frame could be proposed based on the variation of von-Mises stress contour by substituting an AA6061 (aluminum 6061 alloy) having tensile strength of 310 MPa grade instead of SAPH440 steels. In addition, the stress ratio variations (stress over fatigue limit) of the rear sub-frame were examined and compared carefully. It could be reached that this approach method could be well established and be contributed for light-weight design guide and the optimum design conditions of the automotive rear sub-frame development.

• Journal of the Korean Wood Science and Technology
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• 제42권2호
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• pp.89-100
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• 2014

Energy consumption statistics in 2005 from the Korea Energy Management Corporation show that building energy usage was about 24.2% of total domestic energy consumption, and 64% of total building energy usage was consumed by residential buildings. Thus, about 10% of total domestic energy consumption is due to the heating of residential buildings. Building energy can be calculated by the configuration of the building envelope and the rate of infiltration (the volume of the infiltration of outdoor air and the leakage of indoor air), and by doing so, the annual energy usage for heating and cooling. Therefore, air-tightness is an important factor in building energy conservation. This investigate air infiltration and various factors that decrease it in timber frame buildings and suggest ways to improve air-tightness for several structural types. Timber frame buildings can be classified into light frame, post and beam, and log house. Post and beam includes Han-ok (a Korean traditional building). Six light frame buildings, three post and beam buildings, one Korean traditional Han-ok and a log house were selected as specimens. Blower door tests were performed following ASTM E779-03. The light frame buildings showed the highest air-tightness, followed by post and beam structures, and last, log houses.

• ETRI Journal
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• 제34권1호
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• pp.138-141
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• 2012

This letter proposes a real-time digital image stabilization system for cell phone cameras without the need for frame memory. The system post-processes an image captured with a safe shutter speed using an adaptive denoising filter and a global color correction algorithm. This system can transfer the normal brightness of an image previewed under long exposure to the captured image making it bright and crisp with low noise. It is even possible to take photos in low-light conditions. By not needing frame memory, the approach is feasible for integration into the size-constrained image sensors of cell phone cameras.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.438-444
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• 2018

Structured light vision system has been widely used in 3D surface profiling. Usually, it is composed of a camera and a laser which projects a line on the target. Calibration is necessary to acquire 3D information using structured light stripe vision system. Conventional calibration algorithms have found the pose of the camera and the equation of the stripe plane of the laser under the same coordinate system of the camera. Therefore, the 3D reconstruction is only possible under the camera frame. In most cases, this is sufficient to fulfill given tasks. However, they require multiple images which are acquired under different poses for calibration. In this paper, we propose a calibration algorithm that could work by using just one shot. Also, proposed algorithm could give 3D reconstruction under both the camera and laser frame. This would be done by using newly designed calibration structure which has multiple vertical planes on the ground plane. The ability to have 3D reconstruction under both the camera and laser frame would give more flexibility for its applications. Also, proposed algorithm gives an improvement in the accuracy of 3D reconstruction.