• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.405-410
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• 2006

This paper presents a control algorithm of supply and exhaust diffusers by recognizing a contaminant source location. CFD analysis has been conducted to calculate steady state airflow and concentration distributions in a model room, which has two supply and two exhaust openings on the ceiling. Calculations have been performed for five cases out of nine different ventilation modes by combining on/off control of the supply and exhaust openings. Local mean residual life times are obtained and compared at 9 internal points for each ventilation case. Depending on the contaminant source location, the ventilation system is operated at an optimum ventilation mode, which can results in maximum exhaust performance.

• 한국태양에너지학회 논문집
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• 제26권2호
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• pp.87-94
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• 2006

The efficiency of ventilation system is one of the most important issues of designing ventilation in high-rise apartment buildings. The purpose of this study is to analyze the ventilation efficiency of ventilation system by experimental study using CO2 gas method. The results of this paper can be summarized as follows; (1) An appropriate ventilation including opening planning, mechanical and hybrid system are required. (2) The supply diffuser of ventilation system should be located near the contaminant source. (3) The return grill should be located along with supply diffuser for proper ventilation. and the return grill should be located near or right above the contaminant source. (4) However, the supply location right above the contaminant source has to be avoided. and the supply diffuser should be installed in module with return grill increase ventilation effectiveness.

• Journal of Korean Society for Atmospheric Environment
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• 제14권E호
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• pp.1-7
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• 1998

This paper presents an experimental study for understanding the indoor air quality in a room. A model room, which had a ceiling-mounted supply and a sidewall-mounted exhaust, was used to examine the effect of air exchange rate (AER) and contaminant source location (CSL) as a function of the elapsed time. A tracer gas method, using carbon monoxide tracer, gas analyzers, and a data acquisition system, was applied to study the ventilation air distribution and the tracer removal efficiency, so-called pollutant removal efficiency, in the model room. The experiment was composed of two parts; firstly the AER was varied to examine its effect on the ventilation air distribution and the ventilation effectiveness and secondly both AER and CSL were considered to determine their effect on the pollutant removal efficiency. It was found that the ventilation effectiveness in the model was proportional to AER but not linearly. It was also found that changing the CSL can improve the pollutant removal efficiency. In some cases, the efficiency improvement by increasing AER was achieved by simply changing CSL.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 총회 및 춘계학술발표회
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• pp.316-319
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• 2005

Contaminated area should be identified for designing polluted groundwater cleanup plan. A methodology was suggested to identify a contaminant plume distribution geostatistically. James & Gorelick (1994) suggested a methodology to evaluate data worth as expected reducing remediation cost. In this study, their methodology was modified to evaluate data worth as expected reducing uncertainty of the contaminant plume distribution. In suggested methodology, the source identification model by Mahar & Datta (2001) using a forward solute transport model is integrated. Suggested methodology was assessed by two simple example problems and its result represented reducing uncertainties of contaminant plume distribution successfully.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2020년도 학술발표회
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• pp.114-114
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• 2020

Water contamination in a water distribution network (WDN) is harmful since it directly induces the consumer's health problem and suspends water service in a wide area. Actions need to be taken rapidly to countermeasure a contamination event. A contaminant source ident ification (CSI) is an important initial step to mitigate the harmful event. Here, a CSI approach focused on determining the contaminant intrusion possible location and time (PLoT) is introduced. One of the methods to discover the PLoT is an inverse calculation to connect all the paths leading to the report specification of a sensor. A filtering procedure is then applied to narrow down the PLoT using the results from individual sensors. First, we spatially reduce the suspect intrusion points by locating the highly suspicious nodes that have similar intrusion time. Then, we narrow the possible intrusion time by matching the suspicious intrusion time to the reported information. Finally, a likelihood-score is estimated for each suspect. Another important aspect that needs to be considered in CSI is that there are inherent uncertainties, such as the variations in user demand and inaccuracy of sensor data. The uncertainties can lead to overlooking the real intrusion point and time. To reflect the uncertainties in the CSI process, the Monte-Carlo Simulation (MCS) is conducted to explore the ranges of PLoT. By analyzing all the accumulated scores through the random sets, a spread of contaminant intrusion PLoT can then be identified in the network.

• 한국산업보건학회지
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• 제10권2호
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• pp.140-149
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• 2000

In industrial field, there are several operations where a horizontal unidirectional airflow is used to control airborne contaminants. When a worker is immersed in a uniform freestream, a recirculating airflow can be created downstream of the worker by the phenomenon of boundary layer seperation. If the contaminant source and the breathing zone are within this near-wake region, high exposure may occur. The investigation for the effect of contaminant source location on worker exposure was performed by using CFD(Computational Fluid Dynamics). The airflow field was numerically calculated by assuming a steady flow and using the standard $k-{\varepsilon}$ turbulence model. As the results were compared with experimental data, the applicability of CFD was successfully verified. Subsequently, the breathing zone concentrations of the worker were predicted and compared with experimental data. The effects of contaminant density and turbulence intensity of freestream on worker exposure were evaluated.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 추계학술발표회
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• pp.204-207
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• 2001

An optimization process for the design of groundwater remediation is developed by simultaneously considering the well location and the pumping rate. This process uses two independent models: simulation and optimization model. Groundwater flow and contaminant transport are simulated with MODFLOW and MT3D in simulation model. In optimization model, the location and pumping rate of each well are determined and evaluated by the genetic algorithm. In a homogeneous and symmetric domain, the developed model is tested using sequential pairs for pumping rate of each well, and the model gives more improved result than the model using sequential pairs. In application cases, the suggested optimal design shows that the main location of wells is on the centerline of contaminate distribution. The resulting optimal design also shows that the well with maximum pumping rate is replaced with the further one from the contaminant source along flow direction and that the optimal pumping rate declines when more cleanup time is given. But the optimal pumping rate is not linearly proportional to the cleanup time and the minimum total pumping volume does not coincide with the optimal pumping rate.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.1031-1033
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• 2013

후쿠시마와 같은 방사선 누출 사고 시 방사선원의 위치를 찾는 일은 방사선 방호 뿐만 아니라 원전 사고의 조속하고 안전한 처리를 위해서도 중요하다. 방사선원의 3차원 위치 탐지는 기존에 방사선 탐지기의 2차원적 방사선 위치 탐지기능에 방사선원의 거리정보까지 추가 제공할 수 있어 방사선 오염원의 제거 및 제염작업에 결정적 역할을 할 수 있다. 본 연구에서는 반도체 센서에 기반한 듀얼(Dual) 방사선 탐지기를 이용한 방사선원 3차원 가시장치 개발 연구의 일환으로 방사선 센서부의 효율적 차폐체 구조설계에 관한 결과를 논하였다. 고하중의 텅스텐 또는 납 차폐체를 MCNP기반으로 최적구조로 설계함으로써 경량의 고효율 방사선원 위치탐지기 구현을 시도하였고, 이를 위해 차폐체의 구조와 두께, 그리고 콜리메이터에 형상의 다양한 변수모델에 대한 방사선 차폐시뮬레이션을 수행하였다. 본 연구의 결과는 향후 실리콘 센서기반의 소형 경량의 3차원 방사선원 탐지 및 가시화 연구에 활용될 예정이다.

• 대한토목학회논문집
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• 제12권2호
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• pp.217-227
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• 1992

본 논문에서는 일계(一階) 및 이계(二階) 신뢰해석법(信賴解析法)을 이용 흙속으로의 오염물 이동을 해석할 수 있는 모델을 개발하였으며 오염이동 모델은 1차원 차분법과 2차원 유한요소법을 이용하였다. 일계(一階) 및 이계(二階) 신뢰성 해석법은 흙의 특성을 제한하는 가정사항이 필요치 않은 확률모델이며 본 해석으로부터 얻어지는 예민도(sensitivity)는 확률해에 큰 영향을 미치는 입력 매개변수에 대한 정보를 제공한다. 1차원 오염물 이동 신뢰성 해석으로 신뢰성해석 프로그램의 유용성과 정밀성을 검증하였으며, 연속 오염원의 2차원 해석과 농도 극한상태 함수를 이용하여 오염물 이동 경로상 지점의 입력변수가 신뢰성해석의 확률해(解)에 미치는 영향을 검토하였다.

• 한국정보통신학회논문지
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• 제24권11호
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• pp.1519-1527
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• 2020

일반적인 방사선 측정장치는 방사능 오염원에 대한 선량률을 측정하는 공간 선량률 탐지 장치와 방사능 오염정보에 대한 2차원 또는 3차원 영상화 장치의 형태로 개발되었다. 이러한 방사선 계측 기법은 각각의 장단점을 가지고 있으나 방사능 사고 지역에서 인명피해를 최소화하며, 빠른 제염을 위해서는 두 가지 탐지 장치의 장점이 모두 필요하다. 방사능 오염원으로부터 방사능 피해를 최소화하기 위해서는 방출되는 방사선에 대한 선량률 뿐만 아니라 어디에서 방출되고 있는지를 빠르게 확인해야 하기 때문이다. 본 논문에서는 방사능 오염원 탐지를 위한 검출 센서와 회전체, 방향성을 갖는 콜리메이터를 이용하여 방사능 오염원에 대한 선량률 및 방향 정보를 실시간으로 측정 할 수 있는 기법을 고안하였다. 회전형 기반의 방사능 탐지 장치는 탐지 센서를 둘러싼 회전체가 회전하며 개구부와 일치할 때 획득되는 방사능 정보와 회전체의 위치정보를 통해 선량률과 방향을 확인할 수 있도록 구성하였으며, 다수개의 홀을 통해 수직, 수평 방향에 대한 측정 기법을 제안하였다. 탐지 결과 수평 방향에서의 탐지 시 방향 정보에 대한 측정오차는 1% 미만으로 확인하였다.