• Computers and Concrete
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• 제8권2호
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• pp.177-192
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• 2011

This research paper aims at computer based modeling of carbonation induced corrosion under extreme conditions and its experimental verification by incorporating enhanced electrochemical and mass balance equations based on thermo-hygro physics with strong coupling of mass transport and equilibrium in micro-pore structure of carbonated concrete for which the previous research data is limited. In this paper the carbonation induced electrochemical corrosion model is developed and coupled with carbon dioxide transport computational model by the use of a concrete durability computer based model DuCOM developed by our research group at concrete laboratory in the University of Tokyo and its reliability is checked in the light of experiment results of carbonation induced corrosion mass loss obtained in this research. The comparison of model analysis and experiment results shows a fair agreement. The carbonation induced corrosion model computation reasonably predicts the quantitative behavior of corrosion rate for normal air dry relative humidity conditions. The computational model developed also shows fair qualitative corrosion rate simulation and analysis for various pH levels and coupled environmental actions of chloride and carbonation. Detailed verification of the model for the quantitative carbonation induced corrosion rate computation under varying relative conditions, different pH levels and combined effects of carbonation and chloride attack remain as scope for future research.

• 한국초전도ㆍ저온공학회논문지
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• 제7권2호
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• pp.21-26
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• 2005

Breakdown characteristics and survival probability of turn-to-turn models were investigated under ac and impulse voltage at 77K. For experiments, two test electrode models were fabricated: One is point contact model and the other is surface contact model. Both are made of copper wrapped by O.025mm thick polyimide film(Kapton). The experimental results were analyzed statistically using Weibull distribution in order to examine the wrapping number effects on voltage-time characteristics under ac voltage as well as under impulse voltage in LN$_{2}$. Also survival analysis were performed according to the Kaplan-Meier method. The breakdown voltages of surface contact model are lower than that of point contact model, because the contact area of surface contact model is wider than that of point contact model. Besides, the shape parameter of point contact model is a little bit larger than that of surface contact model. The time to breakdown t$_{50}$ is decreased as the applied voltage is increased, and the lifetime indices slightly are increased as the number of layers is increased. According to the increasing applied voltage and decreasing wrapping number, the survival probability is increased.

• 한국지구과학회지
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• 제28권5호
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• pp.545-555
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• 2007

Ocean general circulation model developed by GFDL on the basis of MOM4 of FMS are examined and evaluated in order to elucidate the global ocean status. The model employs a tripolar grid system to resolve the Arctic Ocean without polar filtering. The meridional resolution gradually increases from $1/3^{\circ}$ at the equator to $1^{\circ}$ at $30^{\circ}N(S)$. Other horizontal grids have the constant $1^{\circ}$ and vertical grids with 50 levels. The ocean is also coupled to the GFDL sea ice model. It considers tidal effects along with fresh water and chlorophyll concentration. This model is integrated for a 100 year duration with 96 cpu forced by German OMIP and CORE dataset. Levitus, WOA01 climatology, serial CTD observations, WOCE and Argo data are all used for model validation. General features of the world ocean circulation are well simulated except for the western boundary and coastal region where strong advection or fresh water flux are dominant. However, we can find that information concerning chlorophyll and sea ice, newly applied to MOM4 as surface boundary condition, can be used to reduce a model bias near the equatorial and North Pacific ocean.

• 한국기계가공학회지
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• 제16권6호
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• pp.139-145
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• 2017

It is necessary to analyze the exact contact position and contact stress of the wheel-rail in order to predict damage to the wheel and rail. This study presents a wheel-rail contact analysis model that considers the deformation of the axle. When a wheel-rail contact analysis is performed using a full three-dimensional model of the wheelset and rail, the analytical model becomes very inefficient due to the increase in analysis time and cost. Therefore, modeling the element-coupling model of the wheel and rail as a three-dimensional element and the axle as a one-dimensional element is proposed. The wheel-rail contact characteristics in the proposed analysis model for straight and curved lines were analyzed and compared with the conventional three-dimensional analysis model. Considering the accuracy of the analysis results and time, the result shows that the proposed analytical model has almost the same accuracy as a full three-dimensional model, but the computational effort is significantly reduced.

• 복식문화연구
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• 제30권3호
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• pp.444-454
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• 2022

Flipped learning research has been applied in various educational fields since 2015 and the educational effects have been discussed in previous literature. In the beauty field, flipped learning research is insufficient; in particular, it is difficult to find research on flipped learning specifically concerning nail beauty education. The purpose of this study is to develop a model for applying flipped learning to nail beauty education which should involve practical training based on theory. Such an approach is considered effective. Data were collected and analyzed focusing on previous studies with flipped learning applied as a research method. The subject of the research is "Nail Color Design 1", a common nail major elective subject at J college. The "Nail Color Design 1" course is a practice-oriented course in the form of theory and practical classes. Consequently, the flipped learning education model for nail beauty was designed by reflecting learners' needs through the ADDIE instructional design model. It was applied based on the education structure of the Pre-class, In-class, and Post-class of the PARTNER instructional learning model. This study deviates from the traditional practical education model, and has educational significance as a practical model in which flipped learning is applied to nail beauty subjects and self-reflection is derived through project practice.

• 품질경영학회지
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• 제50권4호
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• pp.665-677
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• 2022

Purpose: The purpose of this study is to analyze the current status and investigate relevant indicators so that R&D performance evaluation suitable for government-funded research institutes can proceed. A suitable performance evaluation model was presented based on the surveyed indicators. Based on the presented performance evaluation model, the importance was analyzed to calculate the weight for each indicator of the performance evaluation model. Methods: The method applied in this study presented a performance evaluation model based on the organizational performance evaluation cases of advanced overseas countries. By using the AHP(Analytic Hierarchy Process) technique, the weight of each indicator of the performance evaluation model was studied. Results: As a result of examining the indicators necessary for the evaluation model, focusing on overseas cases, 13 evaluation items were derived. A weight was calculated for the importance of the study results. And the scientific/technical research results showed the highest excellence. Conclusion: Key indicators of performance evaluation suitable for government-funded research institutes were derived and presented through detailed modeling in three stages. A realistic model that can objectively evaluate the performance of government-funded research institutes was proposed using the AHP technique.

• 대한인간공학회지
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• 제32권2호
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• pp.159-165
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• 2013

Objective: The aim of this study was to predict human performance time in finding objects on multi-display monitors using ACT-R cognitive architecture. Background: Display monitors are one of the representative interfaces for interaction between people and the system. Nowadays, the use of multi-display monitors is increasing so that it is necessary to research about the interaction between users and the system on multi-display monitors. Method: A cognitive model using ACT-R cognitive architecture was developed for the model-based evaluation on multi-display monitors. To develop the cognitive model, first, an experiment was performed to extract the latency about the where system of ACT-R. Then, a menu selection experiment was performed to develop a human performance model to find objects on multi-display monitors. The validation of the cognitive model was also carried out between the developed ACT-R model and empirical data. Results: As a result, no significant difference on performance time was found between the model and empirical data. Conclusion: The ACT-R cognitive architecture could be extended to model human behavior in the search of objects on multi-display monitors.. Application: This model can help predicting performance time for the model-based usability evaluation in the area of multi-display work environments.

• 자원환경지질
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• 제51권2호
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• pp.121-130
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• 2018

KAERI Underground Research Tunnel(이하 KURT)는 한국원자력연구원의 연구지역에 건설된 지하처분연구시설이다. 현재 KURT에서는 방사성폐기물의 심층 처분의 주요 핵심 요소인 공학적 방벽과 천연방벽에 대한 연구를 수행하고 있다. 본 연구에서는 심부영역의 부지특성평가기술을 구축하기 위해 수행된 KURT 연구지역의 부지특성조사를 종합하여, 부지 지질모델을 구축하고, 이로부터 3차원 수리지질모델을 도출하였다. 연구지역에서 수행된 지질조사와 시추공 조사 결과를 이용하여 분석한 결과, 수리지질학적 관점에서 중요한 풍화대, 상부 단열암반대, 하부 단열암반대와 심부 영역에 존재하는 결정론적 단열대를 정의하여 이들을 3차원으로 모형화 하였고, 구축된 지질모델과 현장수리시험 결과를 종합하여 지하수유동모델링 및 처분 안전성 평가에 주요한 입력 자료가 될 수리지질모델을 도출하였다.

• 기술혁신학회지
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• 제1권3호
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• pp.326-337
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• 1998

This study aims to propose the model of functional specialization for university and the selection of research university in Korea. This study propose that we diversify universities into three categories ; research university, educational university, and technical university. Considering the current research capability and future research prospect of Korean universities, this study found that 8 universities could be classified as research university. However, in light of a balanced regional growth of research system two more universities could be designated as research university.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4322-4328
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• 2022

The two-fluid model is widely used to describe two-phase flows in complex systems such as nuclear reactors. Although the two-phase flow was successfully simulated, the standard two-fluid model suffers from an ill-posed nature. There are several remedies for the ill-posedness of the one-dimensional (1D) two-fluid model; among those, artificial viscosity is the focus of this study. Some previous works added artificial diffusion terms to both mass and momentum equations to render the two-fluid model well-posed and demonstrated that this method provided a numerically converging model. However, they did not consider mass conservation, which is crucial for analyzing a closed reactor system. In fact, the total mass is not conserved in the previous models. This study improves the artificial viscosity model such that the 1D incompressible two-fluid model is well-posed, and the total mass is conserved. The water faucet and Kelvin-Helmholtz instability flows were simulated to test the effect of the proposed artificial viscosity model. The results indicate that the proposed artificial viscosity model effectively remedies the ill-posedness of the two-fluid model while maintaining a negligible total mass error.