• Journal of the Korean Society of Safety
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• v.29 no.1
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• pp.59-63
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• 2014

Smoke is one of the most critical factor when escaping from the fire since it reduces visibility and interrupts finding emergency exit lights. Therefore, it is recommended that an evacuation simulation program should incorporate the smoke factor. In addition, it is suggested that the program should include not only the unilateral damage by the smoke but also the detour evacuation by risk communication. In this study, MAS (Multi Agent System)-based simulation program which incorporates the reduced walking speed by smoke and adopts the dispersion evacuation logic during escaping from the fire. To make comparison, a commercial evacuation program, Pathfinder was used. It was found that the simulation results of MAS (Multi Agent System)-based program is better than Pathfinder in terms of safe evacuation. It means that evacuation simulation need a additional evaluation categories that include not only quick evacuation time but also safe evacuee number.

• Journal of the Korea Safety Management & Science
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• v.14 no.3
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• pp.159-166
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• 2012

A*algorithm is highly useful to search the shortest route to the destination in the evacuation simulation. For this reason, A*algorithm is used to evaluate the evacuation experiment by the computer simulation. However there are some problems to analyze the outcome in relation to the reality. Because all the people in the building are not well-informed of the shortest route to the exit. And they will not move to the disaster spot though it is shortest route to the exit. Therefore, evacuation simulation program based on A*algorithm raise a problem of bottleneck phenomenon and dangerous result by damage surrounding the disaster spot. The purpose of this research is to prove the necessity for dispersion evacuation simulation by Multi agent system to solve the problems of the existing evacuation simulation program based on A*algorithm.

• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2195-2206
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• 2021

In order to mitigate the damage caused by accidents in nuclear power plants (NPPs), evacuation strategies are usually managed on the basis of off-site effects such as the diffusion of radioactive materials and evacuee traffic simulations. However, the interactive behavior between evacuees and the accident environment has a significant effect on the consequential gap. Agent-based modeling (ABM) is a method that can control and observe such interactions by establishing agents (i.e., the evacuees) and patches (i.e., the accident environments). In this paper, a radiological emergency evacuation model is constructed to realistically check the effectiveness of an evacuation strategy using NetLogo, an ABM toolbox. Geographic layers such as radiation sources, roads, buildings, and shelters were downloaded from an official geographic information system (GIS) of Korea, and were modified into respective patches. The dispersion model adopted from the puff equation was also modified to fit the patches on the geographic layer. The evacuees were defined as vehicle agents and a traffic model was implemented by combining the shortest path search (determined by an A ^* algorithm) and a traffic flow model incorporated in the Nagel-Schreckenberg cellular automata model. To evaluate the radiological harm to the evacuees due to the spread of radioactive materials, a simple exposure model was established to calculate the overlap fraction between the agents and the dispersion patches. This paper aims to demonstrate that the potential of ABM can handle disaster evacuation strategies more realistically than previous approaches.

• Journal of the Korean Society of Safety
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• v.28 no.3
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• pp.118-122
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• 2013

For safe evacuation in the fire disaster, the evacuees must find the exit and evacuate quickly. Especially, if the evacuees don't know the location of the exit, they have to depend on the evacuation guidance system. Because the more smoke spread, the less visibility is decreasing, it is difficult to find the way to the exit by the naked eye. For theses reasons, the evacuation guidance system is highly important. However, the evacuation guidance system without change of direction has the risk that introduce to the dangerous area. In the evacuation safety assessment scenario by the evacuation simulation has the same problem. Because the evacuee in the simulation evacuate by the shortest route to the exit, the simulation result is same like the evacuation without the evacuation guidance system. In this study, it was used with MAS (Multi Agent System)-based simulation program including the evacuation guidance system to implement the change of evacuation by fire. Using this method, confidence of evacuation safety assessment can be increase.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.5
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• pp.1-7
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• 2010

Since subway fire disaster at Daegu, Korea smoke control system and passengers evacuation distance has been focused to reform. Existing smoke control facilities need to expand volume of ventilation capacity however, the complicate subway station structure can hardly react dispersion of smokes from massive subway cabin fire. Smoke flow at platform level move upward thought vertical stairway and passengers evacuation goes with same direction. The victims of evacuees from subway station fire mainly due to exposure of heat radiation and smoke. The study demonstration the effect of downward evacuates stairway system by separating evacuation route to smoke movement pass way including saving times of evacuation.

• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.196-205
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• 2016

Background: The emergency planning zone (EPZ) of the city of Busan is divided into the precautionary actions zone (PAZ) and the urgent protective action planning zone; which have a 5-km radius and a 20-km to 21-km radius from the nuclear power plant site, respectively. In this study, we assumed that a severe accident occurred at Shin-Kori nuclear unit 3 and evaluated the dispersion speed of radiological material at each distance at various wind speeds, and estimated the effective dose equivalent and the evacuation time of PAZ residents with the goal of supporting off-site emergency action planning for the nuclear site. Materials and Methods: The total effective dose equivalent, which shows the effect of released radioactive materials on the residents, was evaluated using the RASCAL 4.2 program. In addition, a survey of 1,036 residents was performed using a standardized questionnaire, and the resident evacuation time according to road and distance was analyzed using the VISSIM 6.0 program. Results and Discussion: According to the results obtained using the VISSIM and RASCAL programs, it would take approximately 80 to 252.2 minutes for permanent residents to move out of the PAZ boundary, 40 to 197.2 minutes for students, 60 to 232.2 minutes for the infirm, such as elderly people and those in a nursing home or hospital, and 30 to 182.2 minutes for those temporarily within the area. Consequently, in the event of any delay in the evacuation, it is estimated that the residents would be exposed to up to $10mSv{\cdot}h^{-1}$ of radiation at the Exclusion Area Boundaries (EAB) boundary and $4-6mSv{\cdot}h^{-1}$ at the PAZ boundary. Conclusion: It was shown that the evacuation time for the residents is adequate in light of the time lapse from the initial moment of a severe accident to the radiation release. However, in order to minimize the evacuation time, it is necessary to maintain a system of close collaboration to avoid traffic congestion and spontaneous evacuation attempts.

• Korean Journal of Remote Sensing
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• v.36 no.5_4
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• pp.1255-1266
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• 2020

In this study, a complex simulation prototype was developed for rapid and accurate prediction of chemical dispersion range in order to reduce human casualties caused by chemical accidents. Complex simulation considered the leakage momentum during the near-field dispersion to take into account the leakage characteristics of the chemical. In the far-distance dispersion process, the wind distribution of the existing model, which was presented uniformly, was improved using weather and topographical information around the accident site, to realize a wind field similar to the actual one. Finally, the damage range was more precise than the existing model in line with the improved near- and far-distance dispersion process. Based on the results of damage range prediction of the complex simulation, it is expected that it will be highly utilized as a system to support policy decision-making such as evacuation and return of residents after a chemical accident.

• Fire Science and Engineering
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• v.18 no.4
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• pp.103-109
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• 2004

The risk of underground space become an important issue of life safety thought the Taeku subway line Accident. It is essential to study of smoke control screen to minimize the damage of human life because of smoke passage and passenger evacuation routes are on the same vertical and dispersion movement. The Fire modeling result shows the effect of fire control screen can save the evacuation time about 2-2.5 times compare to existing the system However, The designs of fire control screen need to be complied with smoke control ventilation system to present optimum design and the position of installation.

• Journal of the Korean Society of Safety
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• v.31 no.3
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• pp.156-161
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• 2016

An accident of an ammonia tank pipeline at a storage plant resulted in one death and three injuries in 2014. Many accidents including toxic gas releases and explosions occur in the freezing and refrigerating systems using ammonia. Especially, the consequence can be substantial due to that the large amount of ammonia is usually being used in the refrigeration systems. In this study, offsite consequence analysis has been investigated when ammonia leaks outdoors from large storages. Both flammable and toxic effects are under consideration to calculate the affected area using simulation programs for consequence analysis. ERPG-2 concentration (150 ppm) has been selected to calculate the evacuation distance out of various release scenarios for their dispersions in day or night. For offsite residential, the impact area by flammability is much smaller than that by toxicity. The methodology consists of two steps as followings; 1. Calculation for discharge rates of accidental release scenarios. 2. Dispersion simulation using the discharge rate for different conditions. This proactive prediction for accidental releases of ammonia would help emergency teams act as quick as they can.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.290-293
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• 2008

In this study, the Computational Fluid Dynamics (CFD) has been used to analyze the smoke movement and the carbon monoxide concentration distribution, both vertically and longitudinally, in a compartment, based on conservation laws. The Fire Dynamics Simulator (FDS) developed by National Institute of Standards and Technology (NIST) was used for numerical simulations using Reynolds averaged Navier-Stokes equations (RANS) model to solve for time-averaged properties. Results show, as a function of time, a detailed distribution of temperature and carbon monoxide concentration changing against the height above the floor and those changes alongside the distance away from the fire source. Fire-induced smoke and toxic gases like CO are more dangerous in a confined space. The result of study may contribute in designing the smoke evacuation system based on the precise tenable condition.