• 천문학논총
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• 제30권2호
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• pp.79-82
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• 2015

The physical and chemical properties of prestellar cores, especially massive ones, are still far from being well understood due to the lack of a large sample. The low dust temperature (< 14 K) of Planck cold clumps makes them promising candidates for prestellar objects or for sources at the very initial stages of protostellar collapse. We have been conducting a series of observations toward Planck cold clumps (PCCs) with ground-based radio telescopes. In general, when compared with other star forming samples (e.g. infrared dark clouds), PCCs are more quiescent, suggesting that most of them may be in the earliest phase of star formation. However, some PCCs are associated with protostars and molecular outflows, indicating that not all PCCs are in a prestellar phase. We have identified hundreds of starless dense clumps from a mapping survey with the Purple Mountain Observatory (PMO) 13.7-m telescope. Follow-up observations suggest that these dense clumps are ideal targets to search for prestellar objects.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 추계학술발표회요약집
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• pp.158-158
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• 1998

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1995년도 추계학술발표회논문집(1)
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• pp.358-363
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• 1995

A study on passive cooling systems for concrete containment of advanced pressurized water reactors has been performed. The proposed passive containment cooling system (PCCS) consist of (1) condenser units located inside containment, (2) a steam condensing pool outside containment at higher elevation, and (3) downcommer/riser piping systems which provide coolant flow paths. During an accident causing high containment pressure and temperature, the steam/air mixture in containment is condensed on the outer surface of condenser tubes transferring the heat to coolant flowing inside tubes. The coolant transfers the heat to the steam condensing pool via natural circulation due to density difference. This PCCS has the following characteristic: (1) applicable to concrete containment system, (2) no limitation in plant capacity expansion, (3) efficient steam condensing mechanism (dropwise or film condensation at the surface of condenser tube), and (4) utilization of a fully passive mechanism. A preliminary conceptual design work has been done based on steady-state assumptions to determine important design parameter including the elevation of components and required heat transfer area of the condenser tube. Assuming a decay power level of 2%, the required heat transfer area for 1,000MWe plant is assessed to be about 2,000 ㎡ (equivalent to 1,600 of 10 m-long, 4-cm-OD tubes) with the relative elevation difference of 38 m between the condenser and steam condensing pool and the riser diameter of 0.62 m.

• 한국태양에너지학회 논문집
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• 제32권4호
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• pp.90-95
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• 2012

Of school buildings, university building requires various case analysis unlike buildings in the elementary, middle and high schools in accordance with its characteristic for variables such as characteristic of department, construction structure and material, the number of persons admitted and schedule. Through the case research on the 'D' university located in Daejeon, this study made a comparison on the monthly and yearly consumption of gas and electricity of the most recent 3 years and implemented analysis on the usage pattern and standby power of air conditioning and heating by the hour and month using PCCS(Power Consumption Consulting System) as respects electricity that is considered to have a possibility of energy-saving. The result of analysis showed that enormous amount of electric power was used during the night time for freeze protection and burst in winter season and standby power was increased in winter season as a result.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.282-287
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• 2011

Of school buildings, university building requires various case analysis unlike buildings in the elementary, middle and high schools in accordance with its characteristic for variables such as characteristic of department, construction structure and material, the number of persons admitted and schedule. Through the case research on the 'D' university located in Daejeon, this study made a comparison on the monthly and yearly consumption of gas and electricity of the most recent 3 years and implemented analysis on the usage pattern and standby power of air conditioning and heating by the hour and month using PCCS(Power Consumption Consulting System) as respects electricity that is considered to have a possibility of energy-saving. The result of analysis showed that enormous amount of electric power was used during the night time for freeze protection and burst in winter season and standby power was increased in winter season as a result.

• Nuclear Engineering and Technology
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• 제54권6호
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• pp.2297-2310
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• 2022

A condensation heat transfer model is essential to accurately predict the performance of the passive containment cooling system (PCCS) during an accident in an advanced light water reactor. However, most of existing models tend to predict condensation heat transfer very well for a specific range of thermal-hydraulic conditions. In this study, a new correlation for condensation heat transfer coefficient (HTC) is presented using machine learning technique. To secure sufficient training data, a large number of pseudo data were produced by using ten existing condensation models. Then, a neural network model was developed, consisting of a fully connected layer and a convolutional neural network (CNN) algorithm, DenseNet. Based on the hold-out cross-validation, the neural network was trained and validated against the pseudo data. Thereafter, it was evaluated using the experimental data, which were not used for training. The machine learning model predicted better results than the existing models. It was also confirmed through a parametric study that the machine learning model presents continuous and physical HTCs for various thermal-hydraulic conditions. By reflecting the effects of individual variables obtained from the parametric analysis, a new correlation was proposed. It yielded better results for almost all experimental conditions than the ten existing models.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.378-380
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• 2003

This paper presents the optimal point for measuring harmonic levels in distribution systems. Harmonic should be measure PCC (Point of Common Coupling), where is extended over distribution systems, but some PCCs are limited for economical and technical reason : for this reason, the harmonic measurement for a real distribution system and computer simulation are performed to find the optimal PCC in this paper.

• 에너지공학
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• 제25권1호
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• pp.56-68
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• 2016

최근 원자력 발전소의 안전성을 획기적으로 향상시키기 위한 연구가 활발하게 진행되고 있으며 특히 피동냉각계통의 연구개발이 아주 중요하게 부각되고 있다. 피동냉각계통의 열전달 방식으로는 응축열전달 양식이 주로 채택되고 있다. 이와 같은 맥락에서 부산대학교 Ahn & Yun (Ahn 등, 2014)은 새로운 수평관내부 응축 모델을 제시한 바 있다. 본 연구에서는 먼저 Ahn & Yun 이 제시한 수평관 응축 모델을 MARS 코드에 삽입하고 PASCAL 실험데이터를 이용하여 평가하였다. 이 평가결과를 통해 Ahn & Yun 모델의 코드적용에 있어 문제점을 규명하고 새로운 적용방법론을 적용하여 다양한 실험데이터로 다시 평가함으로써 MARS 코드의 향상된 응축 열전달 해석 능력을 확인하였다.

• 융합정보논문지
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• 제11권11호
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• pp.277-287
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• 2021

본 연구의 목적은 퍼스널컬러를 정량적으로 진단할 수 있는 모델을 구축하는 것이다. 현재 사용되고 있는 대표적인 퍼스널컬러용 색채 시스템들은 퍼스널컬러 진단 유형을 지나치게 단순화하거나, 진단 유형간의 객관화된 차이를 구별하기 어렵다는 한계를 가진다. 이를 보완한 새로운 색채 시스템을 개발하기 위해 논리적 배색이 가능한 PCCS 색체계를 도입하고, 색이 가지는 주요 4속성을 토대로 재분류하였다. 기존 색채 시스템보다 다양한 20개의 진단 유형을 제안하였으며, 정량적 방법을 피험자와의 어울림 정도를 평가하여 최적화된 유형을 찾을 수 있게 하였다. 평가 결과를 기호화하여 대입하면 피험자에게 맞는 유형이 도출되는 매트릭스를 고안하여 실험자의 개별 역량과 주관의 개입을 최소화하였다. 최종적으로 속성진단, 기호화, 계절진단의 세 단계로 이루어진 퍼스널컬러의 정량적 진단 모델을 구축하였다. 이는 기존 진단 방법에 다양성, 신뢰성, 정확성을 부여할 것이라 볼 수 있다.

• 디지털융복합연구
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• 제17권6호
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• pp.349-354
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• 2019

본 연구는 공주대학교 내 설치된 공공환경조형물과 설치환경, 학내 이용자가 조형물을 관람하고 느끼는 감성이미지, 색채 계획 시 선호하는 색상과 감성이미지를 측정 분석하는 연구이다. 연구는 학내 설치된 조형물 분석 및 학생들을 대상으로 한 설문으로 진행되었다. 연구 결과 학내 환경조형물에 대한 이용자의 인식 및 조형물 제작 시 고려되어야 할 지향점을 제안할 수 있었다. 본 연구는 학내 설치된 공공 환경 조형물의 색채에 대하여 학술적으로 접근하고, 향후 색채계획단계에서 유의해야할 요소들을 제안하고 있다. 따라서 학내 조형물을 설치 기획할 때에 적절한 가이드라인을 제시 할 것으로 기대된다.