• Journal of Advanced Marine Engineering and Technology
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• v.36 no.3
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• pp.368-377
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• 2012

Most tunnel simulations have been focused on the thermal field and the critical velocity for suppression of hot back-layering flow in case of fire and on the characteristics of a tunnel fire in terms of the flame propagation and the toxic gas generation. In this paper, a comparative study of the flow characteristics of polluted air with no heat source in a tunnel model opened and closed at both end sides is implemented into a recognized CFD simulation code. The model is used to investigate the flow characteristics depending on the three different Reynolds numbers of 640, 1270 and 2120, which have been chosen by the flow velocities of 0.3, 0.6 and 1.0 m/s through the inlet. The results of this study have shown that the CFD predictive and experimental approaches are available in qualitatively studying the correlation of flow behaviors for a better tunnel design.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.26-27
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• 2017

In this study, the cracking characteristics of cured pastes at 800℃ were investigated by X-ray CT. The test specimens were fabricated with and without aggregate, and the heating rate condition was applied at rapid heating (10.0℃/min). It is considered that the rapid heating condition does not cause a temperature gradient phenomenon because the temperature difference between the surface and the center of the sample is small due to a low heating rate unlike an actual fire. The cracking condition of the specimens without aggregate was more severe than that of specimens with aggregate.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.267-272
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• 2010

전 세계적으로 수많은 고층 건축물이 건설되고 있다. 건축물의 높이가 높아질수록 비상시 필요로 하는 유효 피난길이와 총 피난시간은 점점 길어진다. 일반적으로 건축물에서의 피난은 지상층의 안전한 공간으로 대피하는 것을 의미하는데 고층 또는 초고층 건축물의 대규모 수직적 공간에서는 하향식 피난뿐만 아니라 상향식 피난도 고려되어야 한다. 이를 위해 본 연구에서는 고층 아파트 1개소를 선정하여 수직적 이동방향에 따른 실물 피난실험을 실시하여 피난특성을 관찰하였다. 본 실험에서 피난자 개개인의 특성을 파악하기 위해 피난자들이 지상층에 도착하자마자 설문조사를 실시하여 피난행동간 개인 고유의 행동데이터를 수집하였고 이를 PASW 18을 활용하여 통계적 해석을 실시하였다.

• Fire Science and Engineering
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• v.17 no.4
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• pp.92-97
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• 2003

It is necessary to build countermeasure for the reduction of flood damage, such as the analysis of shelter activities of local residents and the publishment of flood informations. The control factors for mental refuge activity by the questionnaire survey were classified and estimated into two categories: internal and external ones. Furthermore, the optimal time for refuse activities related to flood risk was derived by hydraulic simulation. The shelter activities considering inundation depth will serve citizen's consensus by exercise, it would aid to support the activities to minimize flood victims.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.120-121
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• 2019

In this study, FT-IR analysis was performed by exposing cement paste to high temperature in order to characterize the change of hydration behavior of concrete structure damaged by fire accident. As the holding time increased, the Al-O vibration region increased due to the increase of Si-O symmetric Ca₂(SiO₄) and Brownilerite, and the OH stretching region tended to increase due to thermal decomposition of Ca(OH)₂.

• Fire Science and Engineering
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• v.10 no.2
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• pp.28-39
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• 1996

A recently developed electro-thermal simulation methodology is used to analyze the behavior of a PWM(Pulse-Width-Modulated) voltage source inverter which uses IGBT(Insulated Gate Bipolar Transistor) as the switching devices. In the electro-thermal network simulation methdology, the simulator solves for the temperature distribution within the power semiconductor devices(IGBT electro-thermal model), control logic circuitry, the IGBT gate drivers, the thermal network component models for the power silicon chips, package, and heat sinks as well as the current and voltage within the electrical network. The thermal network describes the flow of heat form the chip surface through the package and heat sink and thus determines the evolution of the chip surface temperature used by the power semiconductor device models. The thermal component model for the device silicon chip, packages, and heat sink are developed by discretizing the nonlinear heat diffusion equation and are represented in component from so that the thermal component models for various package and heat sink can be readily connected to on another to form the thermal network.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1970-1976
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• 2008

Since Daegu subway station fire killed 192 citizens in 2003, the demands about safety MRT operation has been increased. Also, the studies and patents for MRT Surveillance are increasing. The related law and system are improving, too. This study suggests the solution for digital surveillance system that has the functions for restricted zone surveillance, the harmful gas and fire surveillance and abnormal behavior surveillance by comparing and analyzing the surveillance systems of advanced countries (United states, Hongkong, Japan etc). Then, we suggest UMS(Unified Message Service) system and image storing system for effective report and management.

• Structural Engineering and Mechanics
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• v.76 no.5
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• pp.613-618
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• 2020

Exhausting oil resources and increasing pollution around the world are forcing researchers to look for new, renewable, biodegradable materials to lead sustainable development. The use of fiber reinforced composites based on natural fibres has increasingly begun as prospective materials for various engineering applications in the automotive, rail, construction and aerospace industries. The natural fiber chosen to make the composite material is plant-based fibre, e.g. jute fibre, and hemp fibre. Thermosetting polymer based Epoxy (LY556) was utilized as matrix material and The composites were produced using hand lay-up technique. The fabricated composites were tested for acoustic testing, thermo-gravimetric analysis (TGA) and flammability testing to asses sound absorption, thermal decomposition and fire resistivity of the structures. Hemp fibre composites have shown improved thermal stability over Jute fibre composites. However, the fire resistance characteristics of jute fibre composites are better as compared to hemp fibre composites. The sound absorption coefficient of composites was found to enhance with the increase of frequency.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.204-210
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• 2019

In case of a fire inside a tunnel, unlike ordinary roads, it is very difficult for a driver to obtain visibility, and a large accident is highly likely to occur. In this study, the smoke behavior, visible distance, and CO concentration of a jet fan were analyzed using the NIST fire simulation (FDS). All analyses were set to HRRPUA (Heat Release Rate Per Area) 3.6MW/m and all the analysis times were set to 600s. In all analyses by CFD, the results were confirmed at y=30m and y=110m, and smoke behavior analysis, visible range analysis, and carbon monoxide concentration were confirmed according to the diameter and flow rate. As the size and flow rate of the jet fan increased, the visibility distance was high at y=30m, and the concentration of carbon monoxide was also confirmed to be 0 ppm. Therefore, proper setting of the jet fan diameter and flow rate will be an excellent solution for fires in tunnels, and taking refuge at upstream area of a re-ventilated fan can reduce the number of casualties.

• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.173-181
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• 2022

Purpose: The purpose of this study was to examine the safety awareness and safety behaviors of personal assistant for visual impairments. Method: This study was targeted at 263 personal assistant for blind people from May to June 2021. Research subjects who wished to participate in the study expressed their intention to participate through the recruitment documents and gave written consent before participating in the study. Result: First, the safety awareness and safety behavior were high among the personal assistants who had practical fire extinguisher practice experience and education on how to act in a disaster situation. In addition, when the emergency rescue method was educated, the life safety awareness and fire safety awareness were high, but there was no difference in the awareness of disaster safety, and the safety behavior was higher. Third, the higher the life safety awareness, fire safety awareness, and disaster safety awareness of personal assistant for the visually impaired, the higher the safety behavior. Conclusion: This study revealed that it is important to provide appropriate safety education to personal assistant and implement a program to raise safety awareness so that the visually impaired can live a safer life.