• 한국안전학회지
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• 제37권6호
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• pp.166-173
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• 2022

A variety of input parameters are taken into consideration while performing a Level 3 PSA. Some parameters related to plume segments, spatial grids, and particle size distribution have flexible input formats. Fine modeling performed by splitting a number of segments or grids may enhance the accuracy of analysis but is time-consuming. Analysis speed is highly important because a considerably large number of calculations is required to handle Level 2 PSA scenarios for a single-unit or multi-unit Level 3 PSA. This study developed a sensitivity analysis supporting interface called MACCSsense to compare the results of the trials of plume segmentation with the results of the base case to determine its impact (in terms of time and accuracy) and to support the development of a modeling approach, which saves calculation time and improves accuracy. MACCSense is an automation tool that uses a large amount of plume segmentation analysis results obtained from MUST Converter and Mr. Manager developed by KAERI to generate a sensitivity report that includes impact (time and accuracy) by comparing them with the base-case result. In this study, various plume segmentation approaches were investigated, and both the accuracy and speed of offsite consequence analysis were evaluated using MACCS as a consequence analysis tool. A simultaneous evaluation revealed that execution time can be reduced using multi-threading. In addition, this study can serve as a framework for the development of a modeling strategy for plume segmentation in order to perform accurate and fast offsite consequence analyses.

• 방재기술
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• 통권23호
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• pp.20-33
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• 1997

• 한국가스학회지
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• 제2권4호
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• pp.7-17
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• 1998

본 연구는 화학장치설비중 가압 염소포화액체 저장탱크의 2상흐름 연속누출에 대한 유해위험거리(또는 독성완충거리)를 정량적으로 예측하기 위한 결과영향 모델링 방법론을 개발하기 위한 것이다. 누출원 모델링은 미환경청의 가이드라인에 근거한 정교한 해석방법과 SuperChems 모델의 자체계산에 의하여 각각 수행되었다. 유해위험성 평가에서 법적 독성규제농도로서 사용되는 STEL, IDLH 및 ERPGs (ERPG-2와 ERPG-3) 농도들에 대하여 유해위험거리를 예측하였다. 비상대응계획 수립시 유해위험성 평가의 가이드라인으로 활용하기 위하여 특히 ERPG-2 농도에 대하여 누출원특성 및 기상변화들의 유해위험거리에 미치는 영향을 고찰하였다.

• 한국가스학회:학술대회논문집
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• 한국가스학회 1998년도 추계학술발표회 논문집
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• pp.103-108
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• 1998

• Korean Chemical Engineering Research
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• 제54권4호
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• pp.582-585
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• 2016

ALOHA, PHAST 등의 사고영향평가 프로그램들을 활용하여 전기 전자 등의 산업 분야에서 많이 쓰이며 인체에 유독한 HF 가 누출되는 사고의 발생 시 대피해야 하는 초기 이격거리에 대한 연구를 수행하였다. 다양한 공정조건과 상태로 저장되어 있는 HF의 사고시나리오를 간단하게 정의하기는 어렵지만 화학물질안전원의 지침대로 10분 내 총 저장량 누출을 최악의 시나리오, 결속된 배관의 일부 파열을 대안의 시나리오로 하여 비상상황을 가정하였다. 그로부터 사고모델링의 시작인 누출속도 산정을 한 후 보수적으로 확산모델링을 적용하여 밤과 낮의 대표적인 기상상태에 따라 일반적인 대피거리로 권고되는 ERPG-2 농도가 도달하는 끝점거리를 구하여 현장에서 신속하게 쓸 수 있는 간단한 그래프와 같은 형태로 제시하였다. 이는 유사시를 대비한 사전적인 성격의 그래프로 화학물질 누출사고 시 신속한 비상대응계획을 수립하는 데 도움이 될 것이다.

• Journal of Astronomy and Space Sciences
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• 제40권1호
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• pp.11-18
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• 2023

The ionosphere is one of the key components of the near-Earth's space environment and has a practical consequence to the human society as a nearest region of the space environment to the Earth. Therefore, it becomes essential to specify and forecast the state of the ionosphere using both the observations and numerical models. In particular, numerical modeling of the ionosphere is a prerequisite not only for better understanding of the physical processes occurring within the ionosphere but also for the specification and forecast of the space weather. There are several approaches for modeling the ionosphere, including data-based empirical modeling, physics-based theoretical modeling and data assimilation modeling. In this review, these three types of the ionospheric model are briefly introduced with recently available models. And among those approaches, fundamental aspects of the physics-based ionospheric model will be described using the basic equations governing the mid-latitude ionosphere. Then a numerical solution of the equations will be discussed with required boundary conditions.

• 천문학회보
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• 제42권1호
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• pp.39.1-39.1
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• 2017

Protoplanetary disks (PPDs) are a natural consequence of star formation and play crucial roles in planet formation. Atacama Large Millimeter/submillimeter Array (ALMA) has provided sub-mm data for the PPDs with a high angular resolution and sensitivity, and it makes us enable to study PPDs in detail. We have developed Packages of Unified modeling for Radiative transfer, gas Energetics, and Chemistry (PUREC), which consists of a self-consistent thermo-chemical model and line and continuum radiative transfer models, in order to interpret and predict the ALMA observations for PPDs. In this talk, we introduce capabilities of PUREC.

• 한국가스학회지
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• 제5권2호
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• pp.1-8
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• 2001

공정의 위험성 평가를 위한 이상트리 작성은 많은 시간과 인력을 요하는 작업으로 대규모 화학공장에 적용하기가 매우 힘들다. 본 연구에서는 화학공정의 이상트리 합성을 위해 장치에서 발생할 수 있는 공정변수의 이탈 및 장치이상에 대한 원인-결과 관계를 나타내는데 필요한 객체지향 지식기반의 프레임워크를 제안하였다. 이상에 대한 원인을 탐색하기 위하여 장치의 객체지향 모델링과 장치간의 연결관계를 이용하여 이탈을 전파하고 이를 통해 이상트리를 합성하였다. 제안된 방법론을 질산 냉각 공정에 적용하여 그 유효성을 검증하였다.

• 전자공학회논문지B
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• 제31B권6호
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• pp.43-52
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• 1994

A design method of rule-based fuzzy modeling is presented for the model identification of complex and nonlinear systems. The proposed rule-based fuzzy modeling implements system structure and parameter identification in the efficient form of ``IF....,THEN...', using the theories of optimization theory , linguistic fuzzy implication rules and fuzzy c-means clustering. Three kinds of method for fuzzy modeling presented in this paper include simplified inference (type I), linear inference (type 2), and modified linear inference (type 3). In order to identify premise structure and parameter of fuzzy implication rules, fuzzy c- means clustering and modified complex method are used respectively and the least sequare method is utilized for the identification of optimum consequence parameters. Time series data for gas furance and those for sewage treatment process are used to evaluate the performance of the proposed rule-based fuzzy modeling. Comparison shows that the proposed method can produce the fuzzy model with higher accuracy than previous other studies.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.449-453
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• 2008

This research focused on analyzing and comparing between the results of hydraulic physical modeling and the results of numerical modeling of Grass Concrete which is newly developed in-situ block system. The physical model was built as a scale of 1:50 by Froude similitude measuring the water levels and the water velocities for before and after vegetation and the effects were analyzed after reviewing the results. In consequence, the water velocities were observed to decrease meanly 19.1%, and the water depth were determined to increase meanly 27.8% in case of the of design flood, $Q=200m^3/sec$. Moreover, the velocities were produced reduction effects of 27.2%, and the water levels were derived from addition effects of the highest 31.3% in case of the probability maximum flood(PMF), $Q=600m^3/sec$. To verifying the hydraulic physical modeling, the numerical modeling was conducted for a close examination of before and after vegetation. HEC-RAS model was for 1 dimensional numerical analysis and RMA-2 was for 2 dimensional numerical analysis. The results of the numerical simulation, under the condition of roughness coefficient calibration, shows similar results of the physical modeling. These satisfactory results show that the accomplished results of hydraulic modeling and the predicted results of numerical modeling corresponded reasonably each others.