• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.3
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• pp.319-325
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• 2003

We investigate the spectra and the pseudospectra in plane Poiseuille flow, plane Couette flow and Blasius flow. At subcritical Reynolds number, the spectra are lied strictly inside the stable complex half-plane, but the pseudospectra are lied in the unstable half-plane, reflecting the large linear transient growth that certain perturbations may excite. It means that the smooth flows may become to turbulent even though all the eigenmodes decay monotonically. We found that pseudospectra is one reason that causes subcritical transition in plane Poiseuille flow and plane Couette flow and bypass transition in Blasius flow.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.176-177
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• 2017

IN order to use it for high-temperature fire, Fireproof boards mainly composed of Ca and Mg used. Korea does not have a fireproof board for explosive high temperatuer fire in tunnel, and it is applying existing fireproof coating. However, when a high-temperature fire(1350℃)with explosion occurs, it can not sustain its strength and can not be destroyed to have fire resistance. Each year, more than 100,100tons of wastes are produced by using Ca as an oyster shell. In this study, we try to determine whether or not to reuse the heat-heated fireproof board.

• Proceedings of the Materials Research Society of Korea Conference
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• 2001.11a
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• pp.79-79
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• 2001

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.234-235
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• 2018

The development of insulation,the most important factor, is slow. The curtain wall market is getting bigger as the bulidings are getting bigger, but the insulation of the window is getting a problem. In order to solve this problem, we want to develop the insulation block used in the window frames. We will examine the insulation effect by using the existing Azon insulation block and the thermal worm convex which is to be developed with Therm 7.4 program.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.21-22
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• 2018

Foamed concrete is a porous concrete that is cured by mixing bubbles into cement slurry. It is lighter than ordinary concrete and is characterized by higher insulation. Lightweight foamed concerte is mainly used as a sandwich panel in Korea, and is also used as a refractory filler in fireproof safes. Studies on lightwight foamed concrete have been carried out on strength,density and thermal conductivity. However, it is confirmed that the research on the fire resistance performance is very limited. Based on this study, fire resistance of lightweight foamed concrete using expanded polystyrene beads is investigated.

• Journal of the Semiconductor & Display Technology
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• v.19 no.3
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• pp.43-48
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• 2020

The demand for stable plasma has been on the rise because of the increased delivery power amount in the chamber for improving productivity, and fast and accurate plasma impedance matching become a crucial performance measure for radio frequency (RF) power system in semiconductor manufacturing equipment. In this paper, the overall impedance matching was understood, and voltage and current values were extracted with voltage - current (VI) probe to measure plasma impedance in real-time. Actual matching data were analyzed to derive calibration coefficient for V and I measurements to understand the characteristics of VI probe, and we demonstrated the tendency of RF impedance matching according to changes in load impedance. This preliminary empirical research can contribute to fast RF matching as well as advanced equipment control for the next level of detailed investigation on embedded system based-RF matching controller.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.583-586
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• 2011

가새골조의 정확한 내진성능평가를 위해서는 실험과 유사한 이력거동과 파단 시점을 잘 예측할 수 있는 해석적 모델이 필요하다. 가새의 이력거동을 모사히기 위해 본 연구에서는 이전 연구자들에 의해 제안된 물리적 이론 모델을 사용하였다. 또한, 가새부재의 국부좌굴에 의한 파단 예측을 위해 피로변수의 보정계수를 도입한 손상 지표를 개선하였다. 결과적으로 실험과 해석 결과를 비교하여 콘크리트충전 각형 강관가새부재의 국부좌굴 효과를 반영한 피로 보정계수를 판폭두께비에 따라 회귀분석을 통해 결정하고, 본 연구에서 제안한 해석 모델의 결과와 이전 연구의 결과를 비교하여 검증하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.426-428
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• 2013

본 논문에서는 해상 데이터 통신방법과 육상 데이터 통신방법 및 이를 이용한 결합된 데이터 통신방법과 시스템을 기초로 보다 상세하게 선박에 내재되어 있는 AIS(Automatic Identification System) 데이터가 주파수 자원 부족 현상으로 인한 데이터 충돌이 발생하는 상황에서 AtoN(항로표지식별장치)가 육상 LTE 채널을 활용하여 선박의 데이터를 우회하게끔 하는 전송 통신방법으로 육상 AIS 기지국과의 통신 채널 충돌의 오차를 줄이는 해상-육상 데이터 통신 시스템이다.

• Solar Energy
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• v.20 no.4
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• pp.9-16
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• 2000

This paper represents the heat storage performance of the flat plate solar collector. This research aims to application for fishing ship on the sea, and the solar collector has among of motions with pitching and rolling thus, this collector has to be a forced type circulation. In this research, we investigated the solar collector performance for the various collector tilt angle. As the experimental results with three types, we found that the S-type collector was excellent.

• Proceedings of the Korea Contents Association Conference
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• 2016.05a
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• pp.161-162
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• 2016

최근 가상현실을 활용한 문화유산 콘텐츠들이 활성화되고 있다. 그러나 그 대부분은 증강현실이나 가상현실을 통해 단순 복원정보나 고증정보를 제공하는 데 그치고 있다. 이글에서는 메타버스의 4가지 유형을 통해 역사교육콘텐츠 개발방안을 살펴보았다. 첫째, 가상세계의 구현을 통해 학생들이 과거 신분별 아바타를 운영해 봄으로써 당시 생활을 체험해 볼 수 있다. 둘째, 증강현실을 통해 현재 체험해 볼 수 없는 사건이나 문화유산의 현장을 경험할 수 있다. 셋째, 시간의 흐름에 따른 사회의 변화를 거울세계를 통해 확인할 수 있다. 넷째, 라이프로깅을 통해 사물의 용도와 주사용자 등 다양한 삶의 방식들을 이해할 수 있다. 이러한 4가지 유형은 사례에 따라서 상호 결합해서 적용할 수 있다. 디지털 시대 역사교육은 단순 정보 전달에 그쳐서는 안된다. 다양한 경험의 확장을 통해 역사상을 제대로 이해할 수 있도록 해야 한다.