• 항공우주기술
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• 제13권2호
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• pp.177-184
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• 2014

우주발사체의 비행안전분석은 정상 및 비정상 비행으로 인해 발생되는 파편의 낙하점 및 낙하분산영역을 예측하여 인명, 선박 그리고 항공기에 미치는 영향을 분석하게 된다. 낙하점 및 낙하분산영역 예측은 우주발사체의 비행안전분석에 필수 요소이다. 특히, 낙하분산영역은 몬테카를로 시뮬레이션을 적용하여 예측될 수 있다. 이럴 경우, 수백회 이상의 반복 계산이 요구되는 몬테카를로 방법은 낙하분산영역을 산출하는데 많은 시간이 소요된다. 본 논문에서는 몬테카를로 시뮬레이션을 대체할 수 있는 방안으로 JU 변환과 다구치 방법을 적용해보고, 세가지 방안의 결과를 비교하여 낙하분산영역 계산을 위해 적합한 방법을 제시한다.

• 환경영향평가
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• 제12권5호
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• pp.323-340
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• 2003

There have been persistent civil appeals in Ansan area against the odor and aerosols emitted from nearby Banwol/Sihwa industrial complex. A fundamental solution for the good air quality has not been addressed yet in spite of the continuous counterplan to reduce odor emission. A systematic and scientific study is needed to examine the reason for the odor episode and to predict the impact coverage of odor pollution. An approach by computational simulation is considered to be adequate to investigate the transportation and the dispersion processes of air pollutants blown by sea breeze toward the coastal city, Ansan. This study has employed various dispersion models to simulate the transportation and the dispersion processes of odor pollutants by a local circulation between land/sea breeze using the data set of emission rates of odorous species from the Banwol/Sihwa industrial complex.

• Nuclear Engineering and Technology
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• 제56권6호
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• pp.2039-2049
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• 2024

The radioactive pollutant could migrate to the downstream urban area under the action of atmospheric dispersion due to the turbulent mixing under actual pollution accidents. A scenario in which radioactive contaminants from the upstream (for example, a nearshore nuclear power plant accident) migrates to the downstream urban blocks have been considered in this study. Numerical simulations using computational fluid dynamics (CFD) are then conducted to investigate the effects of the urban morphology (building packing density and layout) on the atmospheric dispersion of radioactive pollutants in this scenario. The building packing density and structure can significantly affect urban areas' mean flow pattern and the turbulent kinetic energy (TKE). The flow pattern and the TKE distribution influence the radioactive pollution dispersion. It is found that the radioactive pollution at the urban canyons is significantly affected by the vertical transport at the canyon. A comparison of the distributions of radioactive and traditional non-radioactive pollutants is also provided.

• 한국항공우주학회지
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• 제49권3호
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• pp.197-204
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• 2021

유도탄의 비행 시험 중 고장 또는 비정상적인 기동이 발생하는 경우 비행을 계속하지 않도록 의도적으로 자폭한다. 이때 파편이 발생하며 안전 지역을 벗어났는지 여부를 실시간으로 추정하는 것이 중요하다. 본 논문에서는 Fully-Connected Neural Network(FCNN)를 이용하여 실시간으로 파편의 예상 낙하 영역 및 낙하 시간을 추정하는 방법을 제안한다. 많은 양의 학습 데이터 생성을 위해 Unscented Transform(UT)를 적용하였으며 신뢰도 확보를 위해 Monte-Carlo(MC) 시뮬레이션과 비교하여 파라미터를 선정하였다. 또한 제안한 방법의 추정 결과를 MC와 비교하여 성능을 분석하였다.

• 한국대기환경학회지
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• 제27권1호
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• pp.87-96
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• 2011

In this study, the AERMOD dispersion model was used for predicting odor concentrations and back-calculating industrial area source odor emission rate. The studied area was Sihwa industrial complex in Korea. Odor samples were collected during two days over a year period in 2009. The comparison between the predicted and observed concentrations indicates that the AERMOD model could fairly well predict average downwind odor concentrations. The results show odor emission rates of Sihwa industrial complex area source were ranged from 0.204 to 2.320 $OUms^{-1}$ (average 0.476 $OUms^{-1}$). The results also show wind speed and direction are important parameters to the odor dispersion.

• 한국항공우주학회지
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• 제49권8호
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• pp.681-688
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• 2021

본 논문은 시험발사체의 비행궤적 및 낙하점 분산 분석에 대해 다룬다. 2018년 11월의 시험발사체 비행시험 전/후에 수행한 비행궤적 및 낙하점 분산 분석 과정을 설명하고 비행시험 결과와의 비교를 통해 분산 분석 방안이 적절하였음을 보인다. 발사체의 궤적 및 낙하점 분산은 발사체 성능 오차 요인 및 대기권에서의 바람 영향을 고려한 6자유도 몬테카를로 시뮬레이션을 통해 이루어진다. 이와 같이 사전에 분석한 결과를 토대로 비행시험 전에 낙하 안전 영역을 설정한다. 결과적으로, 시험발사체는 사전에 분석한 궤적 및 낙하점 분산 범위 내에서 안전하게 비행하였다.

• 환경영향평가
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• 제6권2호
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• pp.81-92
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• 1997

This paper presents the results from the comparison analysis and evaluation between the air pollutant dispersion modeling results and the observation data in the area within a 10 km radius from the Boryong thermal power plants. The observation data used in this study were the air pollutant concentrations which had been continuously measured from 8 locations around the Boryong power plants by TMS(tele-monitoring system) for 3 months from September to November, 1996. The short-term and long-term predictions were carried out using ISC3 model and LPDM(Lagrangian Panicle Dispersion Model). The results of ISC3 modeling in a short-term showed highly as 0.7 in a correlation coefficient, but in a long-term showed just 0.54. On the other hand, LPDM showed 0.78 in a correlation coefficient for a long-term, but in a short-term showed highly value than the observation concentrations.

• 환경영향평가
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• 제7권1호
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• pp.35-48
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• 1998

Gaussian type models have limitations on predicting a detailed description of the near flow and pollution leads over complex terrains under neutral atmospheric conditions. Also, most models used recently have lack of ability to include atmospheric reactions. The model based on the numerical solution of the time-averaged Navier-Stokes equations and conservation equations needs to be developed to improve the limitations mentioned above. When the model was applied to the Shihwa area where the tracer experiment had been carried out, the simulation results have a great difference from the experimental results. There are two reasons that make the difference between the results by the model and the experiment. First, the Shihwa area is not a complex terrain. Second, meteorological data is insufficient. Therefore, the model should be applied to predict the dispersion of air pollutants over complex terrain rather than flat terrain in order that the model could be verified because the model was developed for the prediction of the dispersion over a complex terrain.

• 환경영향평가
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• 제14권5호
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• pp.291-303
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• 2005

Impact pathway analysis(IPA) is a bottom-up approach to estimates health and environmental risks from emissions of classical pollutants (eg. $PM_{10}$, $SO_2$, $NO_x$ and CO). The model starts from the emission rates of facility, calculates the yearly mean concentrations of pollutants at the ground level using atmospheric dispersion models. After this, proper epidemiological exposure-response functions are applied to determine the impact on the receptors. Finally the methodology can monetise the calculated physical impact on the basis of selected economic evaluation. The aim of this study is to evaluate an external cost of virtual point source in Suwon area using IPA. The results shows minor modification of local input data can make it possible to apply the model to Suwon area.

• 환경영향평가
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• 제14권6호
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• pp.427-441
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• 2005

In order to choose proper dispersion model and emission factors suitable in Korea in evaluating the effect of pollutants emitted by the vehicles in highway on nearby area, various road dispersion models and vehicle emission factors were reviewed. With theoretical inter-comparisons of the exiting models for line source, CALINE 3 and CALINE 4 models which were suggested by US EPA were selected as the road dispersion models for further evaluation with the measurement. The emission factors suggested by Korean Ministry of Environment was turned out to be appropriate since the classification of vehicle kinds was simple and easy to apply in Korea. The comparisons of predicted concentrations by CALINE 3 and 4 models with the measurements in flat, fill and bridge road types showed that CO and PM-10 were in good agreements with experiments and the differences between CALINE 3 and 4 models are negligible. The model concentrations of $NO_2$ by CALINE 4 were also in good agreement with the measurement but those by CALINE 3 were over-predicted. The discrepancies in CALINE 3 model were due to rapid decay reaction of $NO_2$ near the highway, which was not included in CALINE 3 model. For the road type with one & two side cutting grounds, the similar patterns as the flat & fill road type for CO, PM10, & $NO_2$ were observed but the number of data for comparison in these cases were not enough to draw the conclusion. These results lead to the conclusion that CALINE4 model is proper in road environmental impact assessment near the highway in flat, fill and bridge road types.