• The KIPS Transactions:PartA
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• v.14A no.4
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• pp.191-196
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• 2007

In the field of computer graphics, Navier-Stokes equations would be used for realistic simulations of smokes and currents. However, implementations derived from these equations are hard to achieve for real-time simulations, mainly due to its massive and complex calculations. Thus, there have been various attempts to approximate these equations for real-time simulation of smokes and others. When the advection terms of the equations are approximated by the Semi-Lagrange methods, the fluid density can be rapidly reduced and small-scale vorticity phenomena are easy to be missed, mainly due to the numerical losses over time. In this paper, we propose an improved numerical method to approximately calculate the advection terms, and thus eliminate these problems. To calculate the advection terms, our method starts to set critical regions around the target grid points. Then, among the grid points in a specific critical region, we search for a grid point which will be advected to the target grid point, and use the velocity of this grid point as its advection vector. This method would reduce the numerical losses in the calculation of densities and vorticity phenomena, and finally can implement more realistic smoke simulations. We also improve the overall efficiency of vector calculations and related operations through GPU-based implementation techniques, and thus finally achieve the real-time simulation.

• Journal of the Korea Computer Graphics Society
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• v.14 no.4
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• pp.1-5
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• 2008

In this paper, we propose an efficient technique for improving the grid based fluid simulation by sub-grid visuals. The detailed turbulency generated efficiently by Vortex Particle Method are blended with the flow fields coming from the traditional incompressible Navier-Stokes solver. The algorithm enables large- and small- scale detail to be edited separately.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2009.04a
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• pp.3-8
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• 2009

2009년 국내에서 실행되는 성능위주설계인(PBD)을 비롯하여 화재안정성평가를 시뮬레이션을 중심으로 사용하고 있는 추세이다. 그러나 현재 국내에서는 자체 시뮬레이션 프로그램의 이용빈도 보다 타국의 프로그램의 이용 빈도가 높은 추세이다. 현재 많이 이용되고 있는 영국의 SIMULEX와 EXODUS가 대표적인 프로그램이 되겠다. 일본의 동경소방청에서 개발된 화재피난 시뮬레이션(FEA)에서는 연기와 화재성상을 고려하여 피난과 연동하여 피난을 실시하고 있다. 따라서 본 논문에서는 FEA가 국내에 적용방안에 합당한지 파악하고자 SIMULEX와 EXODUS 비교를 실시하여 FEA의 개선점을 도출하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.4
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• pp.830-838
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• 1990

본 연구에서는 에지 드롭 현상이 가장 심하게 나타나고 있는 M-class 저급 무 방향성 규소 강판을 대상으로 MKW압연기의 롤 탄성변형 해석을 컴퓨터 시뮬레이션을 통하여 수행함으로써 에지 드롭을 최소화할 수 있는 개선책을 마련하였고 실제 현장 압연실험을 통하여 그 결과를 확인하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.497-498
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• 2018

In the fire scene, it is difficult to see 1m ahead because of power failure, smoke and toxic gas, even with thermal imaging camera and Xenon searchlight. Analysis of the smoke particles in the fire scene shows that even if the smoke is $5{\mu}m$ or less in wavelength, it is difficult to obtain a front view when using a conventional thermal imaging camera if the visual distance exceeds 1 meter. In the case of black smoke with a particle wavelength of $5{\mu}m$ or more, a space permeation sensor technology using various sensors other than a single sensor is required because chemical materials, gas, and water molecules are mixed. Firefighters need a smoke detection technology for smoke detection and spatial information visualization for forward safety view.In this paper, we design the interface of the information processing system with 32bit CPU core and peripheral circuit. We also implemented and simulated the interface with Lidar sensor. Through this, we provide interface that can implement information processing system of human enhancement fire helmet in the future.

• Fire Science and Engineering
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• v.24 no.2
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• pp.133-138
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• 2010

Recently, evacuation safety of a resident of building become the major concern, because building has been higher and more complicated. Buildings in Korea should install the natural smoke venting or mechanical smoke exhaust equipment according to the building law. The smoke control is the most important to guarantee the evacuation safety. This study evaluate the influence to the height and temperature of smoke layer by enlarging smoke vent size and operating sprinkler system using CFAST (Version 6). Smoke venting size is larger, the effect to height and temperature of smoke layer is increased in below 5 MW fire. But, the correlation of these is decreased in above 10 MW fire. The case that opened smoke vent and sprinklered are applied, life safety criteria are satisfied regardless of fire size. After design the fire scenario according to the service and size of building. Install the smoke vent suitable for the fire size and verify that by experiment or simulation.

• Fire Science and Engineering
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• v.26 no.6
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• pp.31-37
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• 2012

In this study, the fire risk of the curtain wall structure was compared with a general structure among the double envelope structure using a fire simulation program. To this end, a fire-story building curtain wall was modeled as virtual using the PyroSim based on a fire simulation program (FDS). And then, the fires occurred in the model, divided by curtain wall non-applied model and applied model, in the same structure and place. To identify the fire characteristics, smoke behavior characteristics, viewing distance, and volume fractions of CO and $CO_2$ were comparative analyzed. As a result, it was identified that the curtain wall applied model quickly filled with smoke from the top floor to under the floor compared to the curtain wall non-applied model. From this study, the fire risk of curtain wall structure was evaluated in detail using the fire simulations.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.1
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• pp.23-27
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• 2011

Due to the rapid development of construction technology with effective land utilization in this nation, many tunnels were and are being built across the country. However, the smoke and the heat generated from tunnel fire are the most important critical factors which may results in both massive personal injury and property damage, especially, due to the closed surrounding of the tunnel. Considering this particular nature of the tunnels, this study aims to install a fire detection system using an optic fiber cable to measure the temperature changes, compare, and analyze the resulted values with the times of temperature changes of the sensor by performing fire simulations under the same condition as a real fire test. From the results, it has been found that the temperature sensor detects a fire occurrence and generates an alarm within one minute after ignition for both a real fire test and a fire simulation alike, and also that the characteristics of temperature changes of the sensor has close relations with the speeds of the currents inside the tunnel. In addition, considering the tunnel fires can affect the evacuation efficiency and the fire extinguishing activities of the fire brigade inside the tunnel, the temperature sensor must be able to search and find the locations and directions of the fires correctly.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.611-613
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• 2017

스마트폰이 일상생활에 보급되면서 모바일로 제작된 콘텐츠들의 연구 개발이 확산되고 있다. 학습, 여가, 운동 등 여러 분야에서 스마트폰으로 개발된 어플리케이션은 사용자로 하여금 스트레스를 줄여주고 편리함을 제공하고 있다. 본 논문은 스마트폰 Camera와 Video View를 이용하여 사용자와 영상 속안의 배우들과 호흡할 수 있는 모바일 1인칭 연기 시뮬레이션 어플리케이션을 설계하고 이를 구현하였다. 스마트폰의 영상에서 배우의 1인칭 모습이 출력되고 사용자가 선택한 명장면을 함께 진행한다. 본 연구를 통해 배우와 사용자 사이의 친밀감을 극대화시키고 잊고 있었던 명장면을 재조명할 수 있는 효과를 만들어 일상생활에서 느끼는 스트레스를 조금이나마 줄여줄 수 있기를 기대한다.

• Fire Science and Engineering
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• v.24 no.2
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• pp.114-119
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• 2010

The fire at a Busan indoor shooting range on November 14, 2009 was reconstructed by using a computational fluid dynamics model for fire simulations, in order to investigate the cause of the heavy death toll in a short period of time. Spread of the flame and smoke, and temperature distribution obtained by fire simulation were compared with the results of fire investigation based on the CCTV recordings. The flame and smoke flew out violently through the door into the cafeteria from the shooting range, and the cafeteria was filled with smoke just within 3 seconds followed by the onset of fire. This is consistent with the CCTV recordings. It was confirmed, as a result, that people in the cafeteria did not have enough evacuation time. The computed temperature at the door knob reached about $1400^{\circ}C$, near its melting point.