• 한국재난정보학회 논문집
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• 제16권4호
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• pp.842-848
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• 2020

연구목적: 노후화된 발전기의 지속 가능한 운영을 위하여 효율적이며, 안전한 운영이 중요하다. 효율적 운영이란 경제적 관점이며, 안전한 운영은 발전 설비의 치명적 사고 발생에 대한 발생 이전의 사전 조치를 말한다. 그러므로 발전기의 지속가능 운영 모니터링을 위하여 관련된 센서 설치와 이를 기반으로 지속 가능에 대한 예측할 수 있는 모델에 대한 연구가 필요하다. 연구방법: 전기와 열에 대한 수요 예측, 엔진의 성능과 이상을 탐지하는 예측, 그리고 재 난 안전에 대한 예측 모델을 제시하였다. 이를 위하여 필요한 센서를 정의하였으며, 이를 기반으로 예측 모델을 각각 개발하여 수행하였다. 연구결과: 수요 예측 모델은 기존의 79%에서 90% 이상으로 예측 정확도를 향상시켰으며, 다른 2개 모델도 시스템의 지속가능한 안정적 운영을 지원하였다. 결론: 노후화된 발전설비의 지속가능 운영을 지원하기 위한 3가지 종류의 예측 모델을 개발하고 이를 제이비주식회사의 발전 설비에 실제 적용하여 운영하고 있다.

• Journal of Veterinary Science
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• 제24권4호
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• pp.53.1-53.12
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• 2023

Background: Mammalian orthoreovirus type 3 (MRV3), which is responsible for gastroenteritis in many mammalian species including pigs, has been isolated from piglets with severe diarrhea. However, the use of pig-derived cells as an infection model for swine-MRV3 has rarely been studied. Objectives: This study aims to establish porcine intestinal organoids (PIOs) and examine their susceptibility as an in vitro model for intestinal MRV3 infection. Methods: PIOs were isolated and established from the jejunum of a miniature pig. Established PIOs were characterized using polymerase chain reaction (PCR) and immunofluorescence assays (IFAs) to confirm the expression of small intestine-specific genes and proteins, such as Lgr5, LYZI, Mucin-2, ChgA, and Villin. The monolayered PIOs and three-dimensional (3D) PIOs, obtained through their distribution to expose the apical surface, were infected with MRV3 for 2 h, washed with Dulbecco's phosphate-buffered saline, and observed. Viral infection was confirmed using PCR and IFA. We performed quantitative real-time reverse transcription-PCR to assess changes in viral copy numbers and gene expressions linked to intestinal epithelial genes and antiviral activity. Results: The established PIOs have molecular characteristics of intestinal organoids. Infected PIOs showed delayed proliferation with disruption of structures. In addition, infection with MRV3 altered the gene expression linked to intestinal epithelial cells and antiviral activity, and these effects were observed in both 2D and 3D models. Furthermore, viral copy numbers in the supernatant of both models increased in a time-dependent manner. Conclusions: We suggest that PIOs can be an in vitro model to study the infection mechanism of MRV3 in detail, facilitating pharmaceutical development.

• 한국안전학회지
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• 제35권1호
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• pp.25-33
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• 2020

In most plant layout optimization researches, MILP(Mixed Integer Linear Programming) problems, in which the objective function includes the costs of pipelines connecting process equipment and cost associated with safety issues, have been employed. Based on these MILP problems, various optimization solvers have been applied to investigate the optimal solutions. To consider safety issues on the objective function of MILP problems together, the accurate information about the impact and the frequency of potential accidents in a plant should be required to evaluate the safety issues. However, it is really impossible to obtain accurate information about potential accidents and this limitation may reduce the reliability of a plant layout problem. Moreover, in real industries such as plant engineering companies, the plant layout is previously fixed and the considerations of various safety instruments and systems have been performed to guarantee the plant safety. To reflect these situations, the two step optimization problems have been designed in this study. The first MILP model aims to minimize the costs of pipelines and the land size as complying sufficient spaces for the maintenance and safety. After the plant layout is determined by the first MILP model, the optimal locations of blast walls have been investigated to maximize the mitigation impacts of blast walls. The particle swarm optimization technique, which is one of the representative sampling approaches, is employed throughout the consideration of the characteristics of MILP models in this study. The ethylene oxide plant is tested to verify the efficacy of the proposed model.

• Nuclear Engineering and Technology
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• 제52권9호
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• pp.2009-2016
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• 2020

A nuclear power plant is a large complex system with tens of thousands of components. To ensure plant safety, the early and accurate diagnosis of abnormal situations is an important factor. To prevent misdiagnosis, operating procedures provide the anticipated symptoms of abnormal situations. While the more severe emergency situations total less than ten cases and can be diagnosed by dozens of key plant parameters, abnormal situations on the other hand include hundreds of cases and a multitude of parameters that should be considered for diagnosis. The tasks required of operators to select the appropriate operating procedure by monitoring large amounts of information within a limited amount of time can burden operators. This paper aims to develop a system that can, in a short time and with high accuracy, select the appropriate operating procedure and sub-procedure in an abnormal situation. Correspondingly, the proposed model has two levels of prediction to determine the procedure level and the detailed cause of an event. Simulations were conducted to evaluate the developed model, with results demonstrating high levels of performance. The model is expected to reduce the workload of operators in abnormal situations by providing the appropriate procedure to ultimately improve plant safety.

• 시스템엔지니어링학술지
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• 제14권1호
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• pp.13-18
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• 2018

Plant Engineering is a series of activities going through following life cycle phases: planning, basic design, detailed design, procurement and construction, commissioning, operation and maintenance, to produce a target product. From among these phases of plant engineering life cycle, a detailed design phase is an important phase producing final design deliveries. Luckily, through technical co-operation and experiences of constructing plants, large Korean engineering companies have accumulated know-hows of efficient detailed designs. However, smaller engineering companies have less experience of performing detailed designs so there is always a risk of causing design errors in the detailed design phase. To mitigate the risk of design errors in the detailed design phase, it is necessary to systematize a concrete activity model of a detailed design phase. In this paper, we have developed a prototype of a detailed design activity model through a widely used function modeling methodology called IDEF0.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.52-56
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• 2009

In this study a dynamic modeling scheme is presented to derive the probabilistic structure of soil water and plant water stress when subject to stochastic precipitation conditions. The newly developed model has the form of the Fokker-Planck equation, and its applicability as a model for the probabilistic evolution of the soil water and plant water stress is investigated under climate change scenarios. This model is based on the cumulant expansion theory, and has the advantage of providing the probabilistic solution in the form of probability distribution function (PDF), from which one can obtain the ensemble average behavior of the dynamics. The simulation result of soil water confirms that the proposed soil water model can properly reproduce the results obtained from observations, and it also proves that the soil water behaves with consistent cycle based on the precipitation pattern. The plant water stress simulation, also, shows two different PDF patterns according to the precipitation. Moreover, with all the simulation results with climate change scenarios, it can be concluded that the future soil water and plant water stress dynamics will differently behave with different climate change scenarios.

• 시스템엔지니어링학술지
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• 제11권1호
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• pp.1-7
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• 2015

The purpose of this paper is to present the results of reengineering of the YGN 3&4 (Yonggwang Nuclear Power Plant, Units 3&4) SDS (Safety Depressurization System) retrofit design and to make recommendations for the improvement in design and design procedure implementing the Systems Engineering (SE) process. YGN 3&4 is a basic model for OPR1000 (the Korean standard 1000 MWe plant). The basic model, herein, represents the reference plant for the OPR1000 development. In the middle of the YGN 3&4 construction, the Korean Nuclear Regulatory Body requested a retrofit of this plant with a means to rapidly depressurize the plant in conformance with a severe accident mitigation requirement. For the reengineering of the SDS in YGN 3&4, V-model and functional and physical architectures have been developed. A SE decision making method has been used for the selection of SDS valves. Finally, recommendations have been made to improve OPR1000 design for the improved operation and enhanced safety.

• Nuclear Engineering and Technology
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• 제51권2호
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• pp.561-572
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• 2019

In the design criterion for the nuclear power plant piping system, the limit state of the piping against an earthquake is assumed to be plastic collapse. The failure of a common piping system, however, means the leakage caused by the cracks. Therefore, for the seismic fragility analysis of a nuclear power plant, a method capable of quantitatively expressing the failure of an actual piping system is required. In this study, it was conducted to propose a quantitative failure criterion for piping system, which is required for the seismic fragility analysis of nuclear power plants against critical accidents. The in-plane cyclic loading test was conducted to propose a quantitative failure criterion for steel pipe elbows in the nuclear power plant piping system. Nonlinear analysis was conducted using a finite element model, and the results were compared with the test results to verify the effectiveness of the finite element model. The collapse load point derived from the experiment and analysis results and the damage index based on the stress-strain relationship were defined as failure criteria, and seismic fragility analysis was conducted for the piping system of the BNL (Brookhaven National Laboratory) - NRC (Nuclear Regulatory Commission) benchmark model.

• 방사성폐기물학회지
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• 제3권4호
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• pp.319-328
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• 2005

본 논문에서 사고로 누출된 삼중수소에 의한 농작물 오염평가 모델을 제시한다. 본 논문에서 제시된 모델은 동적격실모델로써 작물의 성장 방정식을 도입한 것이 특징이며, 이로부터 삼중수소 피폭시 작물의 성장단계에 따른 오염 정도를 예측할 수 있다. 시스템은 크게 대기, 토양, 작물격실로 구성되며, 격실의 삼중수소 농도 변화는 비선형 상미분방정식으로 표현되므로 시간에 따른 각 격실의 삼중수소 농도가 계산된다. 모델의 검증을 위해 배추 및 무에 대한 삼중수소 피폭 실험을 수행하였다. 생육단계별 오염 효과를 조사하기 위해 각기 다른 생육단계에 있는 배추와 무를 독립적으로 HTO 증기에 노출시켰으며, 피폭 후 오염된 작물의 tissue free water tritium(TFWT) 및 organically bound tritium(OBT) 농도를 측정하였다. 측정된 작물 부위별 삼중수소 농도 데이터와 모델 예측 값은 대체로 잘 일치하였다.

• 한국시뮬레이션학회논문지
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• 제20권4호
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• pp.49-58
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• 2011

국산 개발 분산 제어시스템의 발전 설비에의 적용을 위해서는 시뮬레이터를 이용한 제어 시스템의 기능 및 신뢰성 등의 검증이 선행되어야만 한다. 본 논문에서는 제어 시스템 검증용 시뮬레이터를 개발하는데 있어서, 제어 모델 중 발전소 기동 초기에 보일러 압력을 조절하고, 정상 운전 중 보일러의 과대 압력 상승을 방지하기 위해 보일러에서 발생한 증기를 복수기로 방출하는 터빈 바이패스 계통의 제어 모델을 개발하였다. 제어 모델 개발을 위해, 통합 시뮬레이션 개발 환경에서 활용가능한 제어 로직 구현 툴을 개발하였다. 또한 개발한 툴의 기능은 개별 기능 블럭의 설계 사양에 기반한 시뮬레이션에 의해 검증을 하였으며, 개발한 툴을 이용하여 고압 터빈 바이패스 계통의 압력 제어 로직을 구현하였다. 500 MW급 표준 석탄화력 발전소 공정 모델과 보일러 제어 모델, 터빈 제어 모델 등 타 계통의 제어 모델과의 연계를 통한 통합 시뮬레이션을 통해 개발한 제어 모델의 효용성을 확인하였다.