• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.681-682
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• 2012

• Smart Structures and Systems
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• 제14권6호
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• pp.1269-1289
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• 2014

With the sub-stepping technique, the numerical analysis in real-time dynamic hybrid testing is split into the response analysis and signal generation tasks. Two target computers that operate in real-time may be assigned to implement these two tasks, respectively, for fully extending the simulation scale of the numerical substructure. In this case, the integration time-step of solving the dynamic response of the numerical substructure can be dozens of times bigger than the sampling time-step of the controller. The time delay between the real and desired feedback forces becomes more striking, which challenges the well-developed delay compensation methods in real-time dynamic hybrid testing. This paper focuses on displacement prediction and force correction for delay compensation in the real-time dynamic hybrid testing with a large integration time-step. A new displacement prediction scheme is proposed based on recently-developed explicit integration algorithms and compared with several commonly-used prediction procedures. The evaluation of its prediction accuracy is carried out theoretically, numerically and experimentally. Results indicate that the accuracy and effectiveness of the proposed prediction method are of significance.

• 비파괴검사학회지
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• 제30권3호
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• pp.181-193
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• 2010

The paper presents an alternative way to classical stereocorrelation. First, 2D image processing of random patterns is described. Sub-pixel displacements are determined using phase analysis. Then distortion evaluation is presented. The distortion is identified without any assumption on the lens model because of the use of a grid technique approach. Last, shape measurement and shape variation is caught by fringe projection. Analysis is based on two pin-hole assumptions for the video-projector and the camera. Then, fringe projection is coupled to in-plane displacement to give rise to 3D measurement set-up. Metrological characterization shows a resolution comparable to classical (stereo) correlation technique ($1/100^{th}$ pixel). Spatial resolution seems to be an advantage of the method, because of the use of temporal phase stepping (shape measurement, 1 pixel) and windowed Fourier transform (in plane displacements measurement, 9 pixels). Two examples are given. First one is the study of skin properties; second one is a study on leather fabric. In both cases, results are convincing, and have been exploited to give mechanical interpretation.

• 대한토목학회논문집
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• 제31권4D호
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• pp.603-611
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• 2011

1997년 온실가스 감축을 위한 교토의정서가 채택된 이후 각 국가들은 대표적인 온실가스인 이산화탄소를 줄이기 위하여 전 산업에 걸쳐 다각적인 노력을 하고 있다. 건설산업에서도 온실가스 배출량을 고려한 Passive Design 이나, LCA기준에 의한 환경영향평가와 같은 소프트웨어적 기술의 개발 그리고 설비시스템의 조정이나 친환경 자재의 개발과 같은 하드웨어적 기술의 개발과 같이 두 가지 형태의 기술이 다양한 방법으로 개발됨으로써 이산화탄소 저감을 시도하고 있다. 그러나 건설산업에서 세부공정을 고려한 이산화탄소 배출과 관련한 연구는 전무하다. 본 연구에서는 철도노반공사 중에서 이산화탄소 배출량이 가장 많은 공정인 토공사를 대상으로 장비조합에 따른 이산화탄소 배출량을 산출하여 장비조합과 이산화탄소 배출량 그리고 공사기간의 상관성을 분석하였다.

• 한국정밀공학회지
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• 제21권4호
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• pp.194-201
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• 2004

Optical fibers are indispensable fer optical communication systems that transmit large volumes of data at high speed. But the aligning technology under the sub-micron accuracy is required for the precise axis adjustment and connection. For the purpose of precise alignment of the optical arrays, in this research, we have developed the 12-axis(with 8 automated axis and 4 manual axis) automatic optical fiber alignment system including the image processing-based searching system, the automatic loading system using the robot and the suction toot and the automatic UV bonding system. In order to obtain the sub-micron alignment accuracy, two 4-axis PC-based motion controllers and the two 50nm resolution 6-aixs micro-stage actuated by micro stepping motors are adopted. The fiber aligning procedure consists of two steps. Firstly, the optical wave guide and an input optical array are aligned by the 6-axis input micro-stage with the IR camera. The image processing technique is introduced to reduce primary manual aligning time and result in achieving the 50% decrease of aligning time. Secondly, the IR camera is replaced by the output micro-stage and a wave guide and two optical arrays are aligned simultaneously before the laser power intensity delivered to the optical powermeter reached the threshold value. When the aligning procedure is finished, the wave guide and arrays are W bonded. The automatic loading/unloading system is also introduced and the entire wave guide handing time is reduced significantly compared to the former commercial aligning system.