• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2006년도 PARALLEL CFD 2006
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• pp.301-305
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• 2006

The Vertical Launching System design is especially complicated by complex flow structure in a plenum with the severe thermal state and high pressure load form the hot exhaust plume. The flow structures are numerically simulated by using the commercial code, CFD-FASTRAN with the axi-symmetrical Navier-Stokes equations. Two different cases are considered; that is, the stationary fire and the moving fire.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.2011-2016
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• 2004

In order to develop a high efficiency fire pump, its performance characteristics with various operating conditions are investigated. The governing equations are derived from making using of three-dimensional Navier-Stokes equations with the standard ${\kappa}-{\varepsilon}$ turbulence model and SIMPLE algorithm. Using a commercial code, CFX, pressure distribution and flow fields in a fire pump are calculated with various ranges of rotating speed 800-2400 rpm. Particularly, calculations with multiple frames of reference method between the rotating and stationary parts of the domain are carried out. With the help of numerical results, correlation formula between the casing pressure and the efficiency is derived.

• 한국대기환경학회지
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• 제33권4호
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• pp.319-325
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• 2017

In this study, the new particulate matter emissions considering condensable PM (CPM) of stationary pollutant sources were calculated to modify the CAPSS emissions based on only filterable PMs in Seoul and Incheon. When the new calculated emissions were compared to the existing filterable PM based emissions of local governments, different contribution patterns of emission sources were found. For example, the proportion of mobile sources was high when the filterable PM was considered; however, the contribution of non-industrial sources was dominant in Seoul when the emissions of CPM were considered. Also, the proportion of energy industrial combustion and manufacturing combustion sources was significant in Incheon when CPM emissions considered. Therefore, it seems to be much desirable to consider CPM emissions for determining adequate locations of collective energy facilities and manufacturing combustion facilities in the future. In addition, CPM should be considered to solve the dust problem nationwide. The emission analysis, diagnosis, prediction and countermeasures using CPM emissions should be appropriately performed.

• 대한공간정보학회지
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• 제24권4호
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• pp.3-11
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• 2016

Sixty four percent of Korean territory consists of forest which is fragile for forest fire. However, it is difficult to detect the disaster-induced damages due to topographic complexity in mountainous areas and harsh weather conditions. For this reason, satellite imaging systems have been widely utilized to detect the damage caused by forest fire. In particular, ground vegetation condition can be estimated from multi-spectral satellite images and change detection technique has been used to detect forest fire damages. However, since Korea has clear four seasons, simple change detection technique has limitation. In this regard, this study applied the NDVI(normalized difference vegetation index) annual cycle modeling technique on time-series of Landsat images from 1991 to 2007 to analyze influence of forest fire of Yangyang-gun, Gangwon-do in 2005 on vegetation condition. The encouraging result was obtained when comparing the areas where forest fire occurs with non-damaged areas. The mean value of NDVI was decreased by 0.07 before and after the forest fire. On the other hand, annual variability of NDVI had been increasing and peak value of NDVI was stationary after the forest fire. It is interpreted that understory vegetation was seriously damaged from the forest fire occurred in 2005.

• 한국화재소방학회논문지
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• 제20권1호
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• pp.43-49
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• 2006

본 논문은 조명설비 중 220V/100W 백열전구의 온도특성과 화재분석에 관하여 연구하였다. 백열전구의 발열에 의한 발화가능성을 실험한 결과 정상상태에서는 최고 $161.9^{\circ}C$로 측정되었다. 밀폐된 공간에서 축 열이 되면 약 $538.1^{\circ}C$까지 상승하는 것으로 나타났다. 유리구를 파손하였을 경우 필라멘트는 공기 중에서 용단되었다. 외부 열에 의한 경우 전구 내부의 가스가 약한 부분으로 분출되었다. 따라서 백열전구는 산소의 공급이 원활하면서 폐쇄된 공간에서 화재의 가능성이 높으며, 가연성 물질 등이 주변에 있다면 화재 가능성이 매우 높은 것으로 나타났다. 백열전구의 외형변화, 재료특성의 변화 등을 통해 화재원인을 규명하는 중요한 자료로 이용될 것이 기대된다.

• 한국정보통신학회논문지
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• 제23권9호
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• pp.1082-1087
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• 2019

영상유고감지시스템은 터널 내 보행자, 낙하물, 정지 차량, 역주행, 화재(화염 및 연기) 등 돌발상황 시에 초동 감지 목적의 시스템으로 최근 도심지의 대심도 지하도로 건설에 따라 중요성이 부각되고 있다. 그러므로 영상유고감지시스템을 대심도 복층터널에 적용하기 위하여 복층터널의 설계 특성을 반영하여 개발하였고, 본 논문에서는 특히 기존 영상유고감지시스템에서는 지원되지 않거나 또는 오감지가 많아 복층터널 환경에 그대로 적용하기 어려웠던 화재 감지를 색 영상 분포, 실루엣 확산 및 통계적 특성 분석을 복합적으로 사용하는 방법을 제안하고, 이를 복층터널 테스트베드 환경에서 차량 실물화재 실험을 통하여 검증하였다.

• 한국화재소방학회논문지
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• 제16권3호
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• pp.1-7
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• 2002

Diffusion and dispersion of injected $CO_2$gas into the $N_2$ gas flow are complex. In the packed column with porous particles the axial dispersion and the extra-particle mass transport as well as the intra-particle mass transport are involved. The pulse spreads by stationary diffusion during the period of arrested flow. Hence, the effect of axial dispersion, and of entrance and exit, as well as that of intraparticle convection should be eliminated during the period. The effective diffusivity was determined experimentally by using the gas chromatography, which is to arrest the gas flow during the period after injecting the pulse. This experiment method hasn't been used often in the field. Effective diffusivities are raised with temperature increasing, and it is quite satisfied com-pared to literature values. In this study, the calculated data of gaseous chemical for extinguish fires could be helpful to appreciate several physical phenomenons. Also, it could be expected that, the calculated data of this study might be very useful for development of excellent gaseous chemical for extinguish fires and improvement of its efficiency.

• 한국군사과학기술학회지
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• 제6권1호
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• pp.21-29
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• 2003

The Strap Down Inertial Measurement Unit(SDIMU) is recently used for the sensor package of the modern underwater vehicles such as torpedoes and unmanned underwater-vehicles. For using SDIMU, an initial alignment must be carried out before the fire or navigation stage. The general initial alignment methods require that a mother vehicle Is a stationary condition or the Inertial Navigation System(INS) of vehicle is received the specific of data navigation from the mother vehicle. But an underwater vehicle dropped from aircraft is hard to satisfy above both necessary conditions of the general initial alignment. So, we suggest a new strap down initial alignment method of an underwater vehicle dropped from aircraft without using any aided sensors. The highlight point of this method is that a period of initial alignment is not before the fire but during running stage to fix alignment error. And we verify it by analyzing various data of S/W simulations, Hardware In the Loop Simulation(HILS) tests and sea trials.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.149-150
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• 2022

In Korea, there is no clearly established technology for diagnosing and evaluating the damage depth of concrete structures created by fire. There have been cases of repairing, reinforcing, and demolishing degraded structures without diagnosing the damage depth. The commonly used phenolphthalein-based carbonate thickness measurement does not satisfy the complete disappearance condition of Ca(OH)₂ in the interval where the relatively stationary flow declines after exposure to high temperatures. Even a small amount of Portlandite[Ca(OH)₂] reacts with a red color, and the damage depth is misjudged. It was confirmed by X-ray diffraction and scanning electron microscope that Ca(OH)₂ existed from 300℃ to 500℃ where the residual compressive strength decreased.

• 대한산업공학회지
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• 제31권4호
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• pp.297-302
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• 2005

Kopzon and Weiss adopted the notion of push-pull into the queueing system recently. We extend this queueing system to the ($N_1,N_2$)-policy version such that the original system corresponds to the special case $N_1=N_2=1$. For the extended system, we perform the cycle analysis and obtain the PGF of the stationary number of customers in the system.