• Proceedings of the KSME Conference
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• 2000.04b
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• pp.491-496
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• 2000

The objective of this study is to increase lift and decrease drag of an airfoil by delaying flow separation with piezo-ceramic actuators. The airfoil used is NACA 0012 and the chord length is 30cm. An experiment is performed at the freestream velocity of 15m/s at which the Reynolds number is $3{\times}10^5$. Seven rectangular actuators are attached to the airfoil surface and move up and down based on the electric signal. At the attack angle of $16^{\circ}$, the separation point is delayed downstream due to momentum addition induced by the movement of the actuators. Drag and lift are measured using an in-house 2-dimensional load cell and the surface pressures are also measured. Lift is increased by 10%, drag is reduced by 50%, and the efficiency is increased to 170%. The flow fields with and without control are visualized using the smoke-wire and tuft techniques.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.255-258
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• 2008

본 연구에서는 이전의 연구를 통해 계단형 공동주택 화재 시 재실자 피난특성 및 연기거동에 관한 연구를 실물실험을 통해 수행한 바 있으나 이때 야기된 문제점들을 적절한 방재설비를 도입함으로써 일부 해소하고자 하였다. 따라서 본 연구에서는 이전의 연구와 동일한 대상 건물과 조건에서 수치해석을 수행하며 특히 계단실에 방재설비(배연팬 등) 설치 유 무에 따른 독성가스의 전파 특성 및 최상층까지의 도달시간등을 비교 검토하였다. 계단형 공동주택에서 층간에 배연팬이 설치되어 작동되는 경우가 배연팬이 없는 경우보다 약 45%의 CO 방출량을 줄일 수 있을 것으로 판단되지만 1층 출입구를 통해 유입되는 공기량은 배연팬이 없는 경우가 배연팬이 설치되어 작동되는 경우보다 약 23% 크기 때문에 이로 인해 제연풍속의 증가를 가져올 수도 있을 것이다.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.474-479
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• 2008

The purpose of this paper is to estimate the fire safety in tunnels with bi-directional and/or congested unidirectional traffic where there may be people on both sides of the fire. Therefore, the spread and movement of smoke are simulated by Fire Dynamic Simulator code under different ventilation systems, longitudinal, semi-transverse, large port exhaust system. And as quantitative risk index, FED (Fractional Effective Dose) for each ventilation system are calculated and compared by existed code developed previous research.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2006.04a
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• pp.103-108
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• 2006

• Tunnel and Underground Space
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• v.20 no.2
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• pp.92-96
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• 2010

In this study, experiments were conducted to evaluate the effectiveness of ventilation equipment in underground fires. Two type of Ventilators were used in experiments. Experiments were carried out using ethanol square pool fire. Maximum heat release rate was about 460kW. Visibility and temperature distribution were evaluated according to mechanical ventilation. In blower type ventilation, visibility was increased and temperature was lowered.

• Journal of Korean Elementary Science Education
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• v.36 no.1
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• pp.1-15
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• 2017

The purpose of this study is to analyze the problems of land and sea breeze model experiment that has presented in $5^{th}$ grade curriculum in chapter "Weather and our lives" and makes better model simulation so that learners can have better and more effective way to study it. To survey the opinions from dedicated teachers about land and sea breeze model experiment, we produced the survey through interview with science exclusive teacher from M elementary school. An elementary science education expert, 3 men of science EdD modified and complemented survey and started Delphi survey to 12 science teachers who have career teaching more than 3 years. The problems found in this survey were 'one heat bulb, short heating time, small temperature difference of water and sand, lack of class time, empty space between sand and water, back of transparent boxes, little amount of scent and the location of the it' etc. But the most of all, it is hard to see the successful result of the experiment. Based on these kinds of investigations, and lots of trial and error, redesigned the new model experiment that has the most similarity to the real one and high probability of success. According to this, it was able to see the smoke forms horizontal movement along the sand and the smoke goes in one circulation cycle. through this experiment, we made a conclusion that although those scientific experiments in textbook were developed through lots of considerations of expert, to consider the aspect of consumer, it needs to reach the educational agreement about simulation experiment so that It can lead to successful experiment and high quality education.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.1
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• pp.27-36
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• 2005

The objective of this study was to analyze the smoke movement and to investigate the effect of exhaust ventilation using by shafts for case of fire in long tunnels. Based on Froude modeling, the 1/50 scaled model tunnel (20 m long) was constructed by acrylic tubes and test were carried out systematically. The results of the shaft height test show that the effect on exhaust ventilation by a shaft delays the propagation time of backlayering, and the temperature decreases as the shaft height increases. If the fire occurs downstream of the shaft, the backlayering develops to get stronger by the shaft exhaust effect and then the propagation of CO and temperature increase along with propagation of CO. That is to say, in the case of fire downstream of the shaft, the shaft has the advantage of smoke exhaust effects, but it might result in a dangerous situation for the escaping passengers due to the more developed backlayering.

• Tunnel and Underground Space
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• v.15 no.1 s.54
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• pp.61-70
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• 2005

The objective of this study was to analyze the smoke movement for the case of fire and to determine the interval between emergency exits in long tunnels. Based on Froude modeling, the 1/50 scaled model tunnel (20 m long) was constructed by acrylic tubes and tests were carried out systematically. From the strong relationship between CO propagation time and distance through the tunnel, it was found that the optimal escaping time was 6 minutes in case of 20MW fire. But, regarding passengers' psychological state under fire, another one minute of delay time should be considered. Therefore, the total escaping time should be estimated by 5 minutes. The interval between the emergency exits for vehicle passengers was calculated by 250 m with respect to the 5 minute of escaping time.

• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.70-74
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• 2015

In this paper, satellite communication based video surveillance system that consisted of ultra-small aperture terminals with small-size smart vision sensor is proposed. The events such as forest fire, smoke, intruder movement are detected automatically in field and false alarms are minimized by using intelligent and high-reliable video analysis algorithms. The smart vision sensor is necessary to achieve high-confidence, high hardware endurance, seamless communication and easy maintenance requirements. To satisfy these requirements, real-time digital signal processor, camera module and satellite transceiver are integrated as a smart vision sensor-based ultra-small aperture terminal. Also, high-performance video analysis and image coding algorithms are embedded. The video analysis functions and performances were verified and confirmed practicality through computer simulation and vision sensor prototype test.

• Tunnel and Underground Space
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• v.14 no.4
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• pp.269-274
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• 2004

In this study reduced-scale experiments were conducted to determine the backlayering distance in tunnel fires. The 1/20 scale experiments were carried out under the Froude scaling using ethanol square pool fire ranging from 8 to 1km in each side with total heat release rate from 2.47 to 12.30 ㎾. It has been found that ventilation velocity increases with aspect ratio(tunnel height/tunnel width). At L$\_$B/$\^$*/ ＜5 the ventilation velocity increases proportional to the backlayering distance from 0.25 power of the heat release rate. However at L$\_$B/$\^$*/ $\geq$5 the ventilation velocity varies as the 0.3 power of the heat release rate.