• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2012.04a
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• pp.420-423
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• 2012

원자력 발전소는 화재 발생 시 대규모 피해를 야기하는 특수한 시설물로서 일반 건축물에 비하여 매우 엄격한 화재 안전 기준을 적용하고 있으며 일반 건축물과 차별화된 화재안전 설계 조건을 요구한다. 본 연구에서는 원자력 발전소의 화재안전성을 평가하기 위한 기초연구로써 원자력 발전소 내 주 제어실(이하 MCR)에 대해 화재시나리오 및 환기조건에 따른 화재해석모델의 계산결과를 비교분석하여 각 해석모델의 특성을 파악하고자 한다. MCR 내 화재안전성을 평가하기 위해 Field Model인 FDS 와 Zone Model인 CFAST를 이용하였으며 NUREG/RC-6850, NUREG/RC-1894에 기초하여 화재시뮬레이션을 수행하였다. 해석결과로써 연기농도, 가시거리, 연층높이 등의 데이터를 분석하여 MCR내의 거주가능 시간을 평가하였으며 이를 통해 원자력 시설물의 안전성 확보를 위한 정량적인 자료를 제공하고자 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.529-534
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• 2004

Millimeter waves are potentially useful for high resolution ranging and imaging in low optical visibility conditions such as fog and smoke. Also, They are used for wide band communications. However, it is necessary to develop a theoretical and experimental understanding of millimeter wave propagation to assess the performance of millimeter wave systems. The intensity fluctuations and mutual coherence function (MCF) describe atmospheric effects on the millimeter wave propagation. Using the quasi-optical method (QOM), an efficient and practical method was suggested to obtain the intensity distribution of the antenna focal plane from MCF which can be determined using meteorological data.

• 한국벤처창업학회:학술대회논문집
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• 2021.04a
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• pp.93-95
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• 2021

새로운 코로나 바이러스 질병(COVID-19)은 많은 사람들의 일상생활에 영향을 끼쳤다. 그로 인해 학교 개학 연기와 재택근무 등으로 가정에서 생활하는 시간이 늘어났다. 정부의 사회적 거리 제한에도 식료품은 여전히 인간의 기본 필수품이다. 전염병이 유행하는 동안 식료품에 대한 소비자의 지출은 온라인 소매상에서 큰 폭의 증가를 보이며 온라인 쇼핑이 더욱 확대되고 있다. 판매 품목 중 신선도가 매우 중요한 요인으로 작용하는 농식품은 다른 제품보다 더딘 온라인 쇼핑의 성장 행태를 보이고 있다. 시장 상황을 보아 제품의 특성으로 인하여 농식품의 온라인 구매에 영향을 미치는 요소는 타 제품군과 다른 것으로 판단된다. 본 연구의 목적은 농식품의 온라인 및 모바일 거래 활성화를 위해 농식품 쇼핑몰의 특성과 혁신성이 구매의도에 미치는 영향력을 분석하는 데 있다. 본 연구는 온라인 농산물 쇼핑몰의 특성이 구매의도에 미치는 영향을 살펴보고, 그 관계에서 농식품의 온라인 및 모바일 거래 활성화를 위한 농식품 쇼핑몰 혁신성이 구매의도에 미치는 영향력을 중심으로 진행한다. 따라서 본 연구에서는 소비자의 혁신성이 농식품의 온라인 및 모바일 거래에서 거래 위험에 대한 저항을 낮추어 구매의도를 증가시키는데 영향을 미칠 것이라는 인과적 경로를 검증하고자 한다.

• 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 Navigation and Port Research
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• v.34 no.6
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• pp.423-427
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• 2010

Land fire receives additional extinguishing methods easily by professional extinguisher. But because of isolation and independence from land when sailing on the sea, ships are difficult to get special help from land. Generally, the death ratio by suffocation is higher than the death rate by flame and to reduce suffocation death ratio, fast evacuation is required. This paper aims to improve survival ratio at ship fires by soot density reduction. This study examines soot density and visibility using FDS. And also examines evacuation time by Pathfinder. The FDS(Fire Dynamic Simulator) is a 3 zone model(Field Model) analysis tool and the patherfinder is a useful analysis tool for evacuation. This research examined about evacuation time using the current regulations of the ship's corridor width and exit width first. And then studied evacuation time again when ship's structure was changed according to the method that is proposed in this paper. And finally compared the results each other.

• Fire Science and Engineering
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• v.27 no.5
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• pp.8-14
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• 2013

In the subway, various fires continue to take place across the world. In the Daegu subway accident in 2003, many people were damaged by shortened visibility range caused by toxic gas and smoke. This paper, assuming that a subway fire happens in the Mandeok Station of the subway system in Busan, analyzed different smoke-spreading situations depending on the ventilation situation at its platform (opening of the train doors, operation of ventilation facilities in the tunnel, and working of fire door), using FDS. The calculation proved that it would be more effective to secure evacuation route when the ventilation facilities of the tunnel are not operated, than when they are on. And, it was also found that the case where the doors of the platform to the escape route and only the platform-facing doors of the subway car on fire office are open would be more effective to ventilation than the case where all the doors are open. And, it was found to be important that the fire doors of the platform are working properly.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.1
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• pp.69-73
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• 2011

Unlike land fires, Fires on board a ship are not likely to be extinguished by skilled human resources using a variety of fire fighting equipments, but have to be brought under control on board a ship itself despite of difficult task. There are more cases of deaths from suffocation by smoke than from an increased temperature by heat in fires on board ships, because crew fail to secure a sufficient visibility range enough to escape from the scene of a fire or to leave the ship as early as possible. On the assumption that the height of ship's accommodation area increases from 2.0m to 2.3m comparable to the height of apartments on the ground in Korea, behaviors of fire smokes between the cases of 2.0m and 2.3m heights were compared and analyzed. Based on the blue print of the existing Training Ship "Hanbada", a new blueprint with the 30 cm height adjustment was additionally created. FDS (Fire Dynamic Simulator), which was created by the NIST in the United States and is the most widely distributed simulator for fires, was used to conduct a simulation and predict results. The results of simulation on the basis of temperature of $60^{\circ}C$ showed a safe evacuation period of time at the position 10m apart from the scene of a fire to increase by 55.8 seconds, when the height of ship's accommodation area increased from 2.0m to 2.3m. The results of simulation on the basis of visibility range of 6m showed the safe evacuation periods of time at the positions 10m, 20m and 30m apart from the scene of a fire to increase by 27.1 seconds, 109.2 seconds and 73.3 seconds, respectively, as the height of ship's accommodation area increased from 2.0m to 2.3m. This means that crew can escape more safely from a scene of fires on board when the height of ship's accommodation area is increased and equal to the height of living room in a building on land.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.4
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• pp.347-365
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• 2020

In order to resolve traffic problems in urban areas and to increase the area of green spaces, tunnels in downtown areas are being increased. Additionally, the application of large port smoke extraction ventilation systems is increasing as a countermeasure to smoke extraction ventilation for tunnels with high potential for traffic congestion. It is known that the smoke extraction performance of the large port smoke extraction system is influenced not only by the amount of the extraction flow rate, but also by various factors such as the shape of the extraction port (damper) and the extraction air velocity through a damper. Therefore, in this study, the design standards and installation status of each country were investigated. When the extraction air flow rate was the same, the smoke extraction performance according to the size of the damper was numerically simulated in terms of smoke propagation distance, compared and evaluated, and the following results were obtained. As the cross-sectional area of the smoke damper increases, the extraction flow rate is concentrated in the damper close to the extraction fan, and the smoke extraction rate of the damper in downstream decreases, thereby increasing the smoke propagation distance on the downstream side. In order to prevent such a phenomenon, it is necessary to reduce the cross-sectional area of the smoke damper and increase the velocity of passing air through the damper so that the pressure loss passing through the damper increases, thereby reducing the non-uniformity of smoke extraction flow rate in the extraction section. In this analysis, it was found that when the interval distance of the extraction damper was 50 m, the air velocity passing through damper was 4.4 m/s or more, and when the interval distance of the extraction dampers was 100 m, the air velocity passing through damper was greater than 4.84 m/s, it was found to be advantageous to ensure smoke extraction performance.

• Fire Science and Engineering
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• v.30 no.4
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• pp.1-5
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• 2016

This research performed tests of Video Fire Detector and criteria of installation to make suggestions regarding the criteria that must be reflected in NFSC 203 by comparing the standards of FM Approvals, UL, ISO7240 and NFPA 72. FM Standard related to Video Fire Detector test has been classified as Smoke, Flame type, but the UL Standard has classified only as a Smoke type. This research examined 6 cases of fire phenomenon detection case in ISO 7240 and 3 cases in NFPA 72, respectively. There are 15 items required for the installation standard of a Video Fire Detector and each field standard is presented as a per installation method. To apply a Video Fire Detector, the pertinent items (the definition of term, detector's classification, structure and function among its test item) must be inserted. In addition, 7 items of the fire test, i.e., the sensitivity adjustment, prevent false alarm, ambient temperature test, the effective sensitivity and detection distance and viewing angle, aging test, flood test, must be applied to the actual test. For installation in the field, the operation environment and levels of illumination, and NFSC 203 must be set, and standards relevant to the sound system, indicators' installation distance, etc. need to be inserted.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.3
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• pp.289-300
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• 2013

This study numerically considered the characteristic of smoke movement and the effect of hot smoke gas on tunnel wall surface temperature during road tunnel fire under boundary condition of fire growth curve that is applied to fire analysis in road tunnels. The maximum heat release rate were 20 MW and 100 MW and tunnel air velocities were 2.5 m/s and velocity induced by thermal buoyancy respectively, also the cooling effect of tunnel wall was considered. As results, when tunnel air velocity was constant at 2.5 m/s during tunnel fire, due to the cooling effect of tunnel wall, the smoke layer was rapidly descent after some distance and it flowed the same patterns at the downstream. When heat release rate was 100 MW (and jet fan was not installed), the maximum temperature of tunnel wall surface has risen up to $615^{\circ}C$. The heat transfer coefficient of tunnel wall surface was varied from 13 to $23W/m^2^{\circ}C$ approximately.