• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.25-36
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• 2021

This study analyzed the causes of flood accidents, such as isolation and lost footing accidents in Dorimcheon, to provide legal and institutional improvements. For cause analysis, Field Investigation, Stakeholder Interview, Report, manual, Law et al. Review, Analysis of water level change characteristics, automatic alarm issuance standard level analysis, and evacuation time according to river control were evaluated. Dorimcheon has the characteristics of a typical urban river, which is disadvantageous in terms of water control. In addition, the risk of flood accidents is high because the section where fatal accidents occur forms sharply curved channels. Tripping and isolation accidents occur in the floodplain watch and evacuation stage, which is the stage before the flood watch and warning is issued. Because floodplain evacuation is issued only when the water level rises to the floodplain, an immediate response according to the rainfall forecast is essential. Furthermore, considering that the rate of water level rise is up to 2.62 cm/min in Sillimgyo 3 and Gwanakdorimgyo, sufficient evacuation time is not secured after the floodplain watch is issued. Considering that fatal accidents occurred 0.46 m below the standard water level for the flood watch, complete control is very important, such as blocking the entry of rivers to prevent accidents. Based on these results, four improvement measures were suggested, and it is expected to contribute to the prevention of Tripping and Isolation Accidents occurring in rivers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.3
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• pp.407-416
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• 2024

Over the past 20 years, there has been a rapid increase in the number and size of subway stations and underground structures worldwide, and the importance of safety for subway users has also continuously grown. Subway stations, due to their structural characteristics, have limited visibility and escape routes in disaster situations, posing a high risk of human casualties and economic losses. Therefore, an analysis of disaster vulnerabilities is essential not only for existing subway systems but also for deep underground facilities like GTX. This paper presents a case study applying a betweenness centrality-based disaster vulnerability analysis framework to the case of Gwanggyo Central Station. The analysis of Gwanggyo Central Station's base model and various disaster scenarios revealed that the betweenness centrality distribution is symmetrical, following the symmetrical spatial structure of the station, with high centrality concentrated in the central areas of basement levels one and two. These areas exhibited values more than 220% above the average, indicating a high likelihood of bottleneck phenomena during evacuation in disaster situations. To mitigate this vulnerability, scenarios were proposed to distribute evacuation flows concentrated in the central areas, enhancing the usability of peripheral areas as evacuation routes by connecting staircases continuously. This modification, when considered, showed a decrease in centrality concentration, confirming that the proposed addition of evacuation paths could effectively contribute to dispersing the flow of evacuation in Gwanggyo Central Station. This case study demonstrates the effectiveness of the proposed framework for assessing evacuation vulnerability in enhancing subway station user safety and can be effectively applied in disaster response and management plans for major underground facilities.

• Fire Science and Engineering
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• v.29 no.3
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• pp.65-69
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• 2015

The university dormitory have various functions and large floating population so in the occurrence of fire, there could be heavy casualties. Also, when university dormitory is located far from fire station, it is difficult to fire brigade arrives on Golden Time. Therefore, university dormitory need response capabilities for fire by itself. This study conducted a simulation experiment on those residing in K University dormitory in Gangwon-do, where site proximity is unfavorable, to observe evacuation characteristics of the occupants. As a result, evacuation is delayed due to a lack of evacuation routes and administrator, some students lack of fire awareness. Also fire brigade didn't arrive on Golden Time. Therefore, to resolve problems it is proposed that a student fire volunteer department.

• Proceedings of the KSRS Conference
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• v.1
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• pp.52-55
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• 2006

It's used to be said that tsunami is a rare event. The recurrence time of tsunami in Sumatra area is approximately 230 years as CalTech Research Group‘s study from paleocoral. However, the tsunami occurred in Indian Ocean on 26 December 2004, 28 March 2005 and 17 July 2006, because the earthquakes still release the energy. To cope with the tsunami disaster, we have to put the much effort on better disaster preparedness. The Tsunami Reduction Of Impacts through three Key Actions (TROIKA) was suggested by Eddie N. Bernard, the director of NOAA/PMEL (Pacific Marine Environmental Laboratory). They are Hazard Assessment, Mitigation and Warning Guidance. The satellite remote sensing has potential on these actions. The medium and high resolution satellite data were used to assess the degree of damage at the six-damaged provinces on the Andaman seacoast of Thailand. Fast and reliable interpretation of the damage by remote sensing method can be used for inundation mapping, rehabilitation and housing plans for the victims. For tsunami mitigation, the satellite data can be used with GIS to construct the evacuation map (evacuation route and refuge site) and coastal zone management. It is also helpful for educational program for local residents and school systems. Tsunami is a kind of ocean wave, therefore any satellite sensors such as SAR, Altimeter, MODIS, Landsat, SPOT, IKONOS can detect the tsunami wave in 2004. The satellite images have shown the characteristics of tsunami wave approaching the coast. For warning, satellite data has potential for early warning to detect the tsunami wave in deep ocean, if there are enough satellite constellation to monitor and detect the first tsunami wave like the pressure gauge, seismograph and tide gauge with the DART buoy can do. Moreover, the new methods should be developed to analyse the satellite data more faster for early warning procedure.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.2
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• pp.117-125
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• 2015

Quantitative risk assessment (QRA) of railway is to create a variety of scenario and to quantify the degree of risk by a result of the product of accident frequency and accident. Quantitative risk Assessment is affected by various factors such as tunnel specifications, characteristics of the fire, and relation of smoke control and evacuation direction. So in this study, it is conducted that how the way of smoke control and the relation of smoke control and evacuation direction affect quantitative risk assessment with variables (the tunnel length (2, 3, 4, 5, 6 km) and the slope (5, 15, 25‰)). As the result, in a train fire at the double track tunnel (Area = $97m^2$), it is most efficient to evacuate to the opposite direction of smoke control regardless of the location of train in train fire. In addition, under the same condition, index risk in mechanical ventilation up to 1/10.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.356-362
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• 2008

This study is intended to evaluate the characteristics of smoke spreading and the appropriateness of evacuation time extended by operation of smoke control system during fire within the underground space of the building structured in compliance with the smoke control system performance criteria from the local fire safety standard in Korea. As a preceding review of this study, the combustibles was categorized and identified their heat release rates. For validate the estimated values, modeling a single underground shop was carried out. And a numerical analysis both in case of smoke control system in operation and the system not in operation was carried out of underground space. From the viewpoint of securing the evacuation time, the results were compared in an attempt to assess the appropriateness of the fire safety criteria.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.7
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• pp.288-292
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• 2016

The purpose of this study was to improve the refuge safety area in the high-rise building type. Each simulation was conducted to evaluate the performance of three types in improving the refuge safety area. Targeting the first 63 floors (no refuge safety area), secondly, to target up to the $30^{th}$ floor (refuge safety area on the $30^{th}$ floor, $47^{th}$ floor) specified in domestic laws, and finally, the $20^{th}$ floor (evacuation safety area on the $20^{th}$ floor, $42^{th}$ floor) were considered as targets. Through this analysis, the following results were obtained : The floor for the refuge safety area through simulations showed that the evacuation time is low. It is necessary to improve the floor for the refuge safety area by using the characteristics of the domestic fire fighting vehicle. The first floor for the refuge safety area from the ground floor differs according to the distance and height of the building floor. However, in the case of a business facility it is 15F, and in the case of apartment housing, it is 20F.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.1
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• pp.51-59
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• 1994

The gas jet pumps serve to preduce a vacuum or can be used as gas jet compressors. These are operated on the same principle as a steam jet vacuum pump : in the driving nozzle the pressure energy of the motive medium is converted into the kinetic energy. In the diffuser the driving jet mixes with the suction medium and the kinetic energy is reconverted into the pressure enegy. The application fields of gas jet ejectors are the evacuation of siphoning installations, the elevation of liquids, the production of vacuum filters, the vacuum supporting airlift system, the evacuation of the suction line of centrifugal pumps and the ventilation of the dangerous gases to the atmosphere. The performance of gas jet ejector is influenced strongly to velocity coefficient of motive nozzle, the distance between the motive outlet to the diffuser inlet and the dimensions of diffuser. This study is performed for the computer aided design of gas jet ejectors in future. Through the present experiments, it is known that the velocity coefficient of the motive air nozzle ranges from 0.91 to 0.95 and the maximum efficiency of gas jet ejector is 24.6%.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2007.04a
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• pp.355-360
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• 2007

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2006.04a
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• pp.156-161
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• 2006