• Korean Institute of Interior Design Journal
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• no.13
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• pp.130-138
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• 1997

This study is to present the visual phenomenon of natural light in the interior space. The continuously changing natural light define the visual phenomenon of the architectural space. First, the objective of this study was finding the importance of the visual phenomena which were generated from correlating natural right with the interior space. And the second was to categorize the factors of the visual phenomenon which can be useful factors for modern interior design practice. As a result of this study, two visual phenomena were classified. First; territorial phenomenon: dividing, partitioning, and sectioning by natural light, Second; phenomena by the inflow methods of natural light; a) by direct inflow; transparency, expansion, and floating, b) by filtering fixtures; the architectural structure, color, and the transluscent material, c) by dramatic spacial present of natural light, d) by the sense of direction of naturel light; continuity, and transformatiov. Found and classified each factor is not presented by itself, rather compounded forms. Because of the limited analysis of modern buildings, these found visual factors can not represent all phenomena. But if we practice these finding factors to design present interior space, it is sure of being very valuable factors to re-introduce the overlooked natural light into interior space.

• Journal of The Korean Association For Science Education
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• v.28 no.3
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• pp.197-210
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• 2008

The purpose of this study is to explore the cases and features of the abductive inference used by young children when trying to explain natural phenomena in everyday life. From observing a 5-year-old's daily activities with his family, and analyzing the data according to the criterion extracted from the form of abductive inference described by C. S. Peirce, a few cases where the child used abductive inferences to explain natural phenomena were found. The abductive inferences in the cases were conducted: (a) based on figural resemblance and behavioral resemblance (b) under the influence by individual belief and communal belief, then (c) resulted in new categorization accompanied by over generalization. Such features of the abductive inference showed the 'double faces'; sometimes encourages and sometimes discourages children's generating better scientific hypotheses and explanations. These results suggest that even young children use abductive inference to explain doubtful natural phenomena in everyday life, although we need to consider carefully with the double aspects of the features of abductive inference for the practical applications to the fields of science education. Finally, several suggestions and following studies for science education are proposed.

• Journal of Digital Contents Society
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• v.9 no.3
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• pp.461-470
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• 2008

There are two methods to express natural phenomena using image processing techniques. One is the presentation of simulations for natural phenomena and the other is the display of images based on script. A lot of people used to get the display using vast data and complicated math formulas. When we get the output images in this way, we will have some problems in time and cost. In this paper, we use fluid images excluding using the complicated math formulas, programming, and taking pictures to present the natural phenomena. We construct the library to express the natural phenomena effectively using 2D images and simulation of fog for the background of oriental painting in 3D space.

• Nuclear Engineering and Technology
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• v.52 no.1
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• pp.27-36
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• 2020

Natural convection and thermal stratification phenomena are found in large water pools that are being used as heat sinks for decay heat removal from the reactor core using passive heat removal systems. In this study, the two-phase (water and air) natural convection and thermal stratification phenomena with conjugate heat transfer in the rectangular enclosure were investigated numerically using ANSYS Fluent 17.2 code. The transient numerical simulations of these phenomena in the full-scale computational domain of the experimental facility were performed. Generation of water vapour bubbles around the heater rod and evaporation phenomena were included in this numerical investigation. The results of numerical simulations are in good agreement with experimental measurements. This shows that the natural convection is formed in region above the heater rod and the water is thermally stratified in the region below the heater rod. The heat from higher region and from the heater rod is transferred to the lower region via conduction. The thermal stratification disappears and the water becomes well mixed, only after the water temperature reaches the saturation temperature and boiling starts. The developed modelling approach and obtained results provide guidelines for numerical investigations of thermal-hydraulic processes in the water pools for passive residual heat removal systems or spent nuclear fuel pools considering the concreate walls of the pool and main room above the pool.

• International Journal of Contents
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• v.2 no.2
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• pp.1-5
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• 2006

The modeling and animation of natural phenomena have received much attention from the computer graphics community. Synthetic of natural phenomena are required for such diverse applications as flight simulators, special effects, video games and other virtual realty. In special effects industry there is a high demand to convincingly mimic the appearance and behavior of natural phenomena such as smoke, waterfall, rain, and fire. Particle systems are methods adequate for modeling fuzzy objects of natural phenomena. This paper presents particle system API(Application Program Interfaces) for generating special effects in virtual reality applications. The API are a set of functions that allow C++ programs to simulate the dynamics of particles for special effects in interactive and non-interactive graphics applications, not for scientific simulation.

• Journal of the Korean Society of Industry Convergence
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• v.3 no.4
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• pp.293-296
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• 2000

We have accumulated the knowledge of the phenomena of external nature under the gravity fields of the earth, but have not the data of the natural phenomena under the high or low gravity fields. It is necessary to research the phenomena of the combustion, heat transfer and the behavior of the living animals under the high or low gravity fields. This paper introduces the mysterious universe in high and low gravity fields from the experimental study by Arai et al.

• The KIPS Transactions:PartB
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• v.10B no.7
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• pp.785-794
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• 2003

Computer simulation of natural phenomena has been inclined to graphic processing for visual reality. This negligence of cosmic causalities in their occurrence and natural laws in their development should lead to limited degree of immersion to the users. We attempt to develop a logical framework for authentic simulation of diverse, unpredictable occurrence and development of natural phenomena (such as solar radiation and wind) based on their associated inherent laws and principles. To this end we structure the relevant objects organized in an ontology and propose a data management method. Then we describe our simulation method for the natural phenomena as delimited in phases and present modeling techniques for qualitative changes of physical objects due to their factors' values beyond normal ranges.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1555-1562
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• 2023

Natural circulation phenomena have been nowadays largely revisited aiming to investigate the performances of passive safety systems in carrying-out heat removal under accidental conditions. For this purpose, assessment studies using CFD (Computational Fluid Dynamics) and also 3D thermal-hydraulic system codes are considered at different levels of the design and safety demonstration issues. However, these tools have not being extensively validated for specific natural circulation flow regimes involving flow mixing, temperature stratification, flow recirculation and instabilities. In the present study, an experimental test case based on a small-scale pool test rig experiment performed by Korea Atomic Energy Research Institute, is considered for code-to-code and code-to-experimental data comparison. The test simulation is carried out using the FLUENT and the 3D thermal-hydraulic system CATHARE-2 codes. The objective is to evaluate and compare their prediction capabilities with respect to the test conditions of the experiment. It was observed that, notwithstanding their numerical and modelling differences, similar agreement results are obtained. Nevertheless, additional investigations efforts are still needed for a better representation of the considered phenomena.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.3166-3175
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• 2022

The most numerical investigations of the thermal-hydraulic phenomena following the loss of the residual heat removal capability during the mid-loop operation of the pressurized water reactor were performed according to simplifications and are not sufficiently accurate. To perform more accurate and more reliable predictions of thermal-hydraulic accidents in a nuclear power plant using computational fluid dynamics codes, a more detailed methodology is needed. Modelling results identified that thermal stratification and natural convection are observed. Temperatures of lower monitoring points remain low, while temperatures of upper monitoring points increase over time. The water in the heated region, in the upper unheated region and the pipe region was well mixed due to natural convection, meanwhile, there is no natural convection in the lower unheated region. Water temperature in the pipe region increased after a certain time delay due to circulation of flow induced by natural convection in the heated and upper unheated regions. The modelling results correspond to the experimental data. The developed computational fluid dynamics methodology could be applied for modelling of two-component single/two-phase natural convection and thermal stratification phenomena during the mid-loop operation of the pressurized water reactor or other nuclear and non-nuclear installations at similar conditions.

• Journal of computational fluids engineering
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• v.20 no.4
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• pp.14-20
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• 2015

Without electirc power to cool down the hot reactor core, passive systems utilizing natural circulation are becoming a big specialty of recent neculear systems after the severe accident in Fukusima. When we consider the natural circulation in a pool, thermal mixing phenomena may start from single phase circulation and can continue to two phase condition. Since the CUPID code, which has been developed for two-phase flow analysis, can deal with the phase transition phenomena, the CUPID would be pertinent to natural convection problems in single- and two-phase conditions. Thus, the CUPID should be validated against single- and two-phase natural circulation phenomena. For the first step of the validation process, this study is focused on the validation of single-phase natural circulation. Moreover, the CUPID code solves the fluid properties by the relationship to pressure and temperature from the steam table considering non-condensable gas effects, so that the effects from variable properties are included. Simple square thermal cavity problems are tested for laminar and turbulent conditions against numerical and experimental data. Throughout the investigation, it is found that the variable properties can affect the flow field in laminar condition, but the effect becomes weak in turbulence condition, and the CUPID code implementing steam table is capable of analyzing single phase natural circualtion phenomena.