• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2006년도 춘계학술대회 논문집
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• pp.447-448
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• 2006

• 대한기계학회논문집B
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• 제23권1호
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• pp.12-24
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• 1999

A computer program has been developed for analyzing the two-dimensional, unsteady conservation equations for transport phenomena in the molten region of twin-roll continuous casting in order to predict the turbulent velocity, temperature fields, and solidification process of the molten steel. The energy equation of the cooling roll is solved simultaneously with the conservation equations of molten steel in order to consider heat transfer through the cooling roll. The results show the velocity, temperature and solidification pattern in the molten region with roll temperature as a function of time. The results for velocity and temperature fields with solidification are compared with those without solidification, giving different thermofluid characteristics in the molten region. We also investigated the effects of revolutional speed of roll, superheat and nozzle geometry on the turbulent flow, temperature and solidification in the molten steel and temperature fields in the cooling roll.

• Journal of Mechanical Science and Technology
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• 제16권1호
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• pp.94-101
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• 2002

Convection-dominated melting in a rectangular cavity is analyzed numerically with particular attention to the multi-cellular flows in the melt. At the earlier stage of the melting, the melt region is quite similar to a cavity with high aspect rati71, where the multi-cellular natural convection appears. Numerical results show that the formation and evolution of the multiple flow cells in the melt region is approximately similar to t]tat of a single-phase flow in a tall cavity with the same aspect ratio; however, the continuous change of the melt region due to the melting affects the detailed process. Also, numerical aspects for the prediction of the detailed flow structure in the melt are discussed.

• Journal of Forest and Environmental Science
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• 제32권2호
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• pp.149-157
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• 2016

Understanding regional characteristics in forest fire occurrence is important to establish effective forest fire prevention policy in Korea. This study analyzed the characteristics of forest fires occurred in 16 administrative districts for recent 25 years (1990~2014) to examine regional characteristics in forest fire occurrence. Forest fire occurrence reflects regional characteristics depending on climatic factors as well as region's society-cultural factors. Results showed that the first cause of forest fire occurrence was carelessness by human activities throughout all administrative districts, however, the second cause depends on regional characteristics. As the results of forest fire occurrence period analyzed for 10 days, the most forest fires occurred in the southern region during January to March, while forest fires in the northern region occurred mostly during March to April. We classified forest fire occurrence patterns into three types (centralized: Gyeonggi-do, dispersal: Busan, horizontally distributed: Gyeongsangnam-do) by multi-temporal analysis for forest fire occurrence period.

• BMB Reports
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• 제31권6호
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• pp.604-606
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• 1998

The nucleotide sequence of two hypervariable regions of the D-loop and the frequency of the 9-bp repeat in the region V of mitochondrial DNA (mtDNA) were investigated in the Korean population. Alignment of these sequences with the published reference revealed a unique pattern of base substitution and deletion compared with those of other races. The deletion and addition frequency of the 9-bp repeat in the region V was also distinct.

• 대기
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• 제19권2호
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• pp.145-154
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• 2009

This study compared the sea surface wind pattern between model results from KMA operational model (RDAPS) and retrieved results from QuickSCAT in the 2006-2007 year. The mean spatial distributions of sea surface wind of RDAPS and QuikSCAT show the prominent seasonal patterns of summer and winter season adjacent to Korean Peninsular. The magnitude of sea surface wind predicted by RDAPS is weaker than that of QuikSCAT in most north Pacific ocean. In summer of 2006 positive bias with the maximum of 1 m/s is appeared in broad region of north Pacific ocean, however. the positive bias region is decreased to small region in 2007. Even though the predicted sea wind by RDAPS is stronger(weaker) than observed one by QuikSCAT in summer (winter), the RDAPS model simulate well the sea surface wind adjacent to Korean peninsular.

• Journal of Astronomy and Space Sciences
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• 제33권3호
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• pp.207-210
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• 2016

Under the assumption of the presence of a medium-scale E × B drift vortex of plasma in the daytime midlatitude F region, and using a simplified ionospheric model, we demonstrate that the E × B drift produces noticeable perturbations in the horizontal distribution of the plasma density in the upper F region. The pattern of ion density perturbations shows two separate medium scale domains of enhanced and reduced ion density with respect to the background. The E × B drift does not produce multiple small-scale ion density irregularities through plasma mixing because of the suppression effect of the field-aligned ambipolar plasma diffusion.

• Journal of Ship and Ocean Technology
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• 제8권1호
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• pp.10-30
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• 2004

High-fidelity RANS simulations are presented for a ducted marine propulsor, including verification ＆ validation (V＆V) using available experimental fluid dynamics (EFD) data. CFDSHIP-IOWA is used with $\textsc{k}-\omega$ turbulence model and extensions for relative rotating coordinate system and Chimera overset grids. The mesh interpolation code PEGASUS is used for the exchange of the flow information between the overset grids. Intervals V＆V for thrust, torque, and profile averaged radial velocity just downstream of rotor tip are reasonable in comparison with previous results. Flow pattern displays interaction and merging of tip-leakage and trailing edge vortices. In interaction region, multiple peaks and vorticity are smaller, whereas in merging region, better agreement with EFD. Tip-leakage vortex core position, size, circulation, and cavitation patterns for $\sigma=5$ also show a good agreement with EFD, although vortex core size is larger and circulation in interaction region is smaller.

• 대한치과의사협회지
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• 제51권11호
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• pp.586-594
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• 2013

The critical factors affecting the esthetics of anterior implants can be summarized as following: 1) Correct positioning of implant fixture 2) Enough amount of alveolar bone 3) Optimum volume of soft tissue. The position of implant is probably the most important factor in obtaining esthetic treatment outcome. The 3-dimensional orientation of implant is determined by the position on the alveolar ridge and its direction. Clinicians often try to mimic natural teeth when fabricating restorations. During the course of esthetic diagnosis and treatment, however, one should not forget to consider the correlation between facial pattern, lips, gingiva, alveolar ridge, as well as remaining dentition. Since anterior region is biologically unfavorable when compared with posterior region, one minor discrepancy in positioning of implant can cause esthetically undesirable treatment outcome. If one understands the biological and prosthetic meaning of implant's 3-dimensional position, he or she can achieve superior esthetic outcome in anterior region.

• 대한원격탐사학회지
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• 제21권1호
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• pp.83-89
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• 2005

This study utilized a spatial region growing segmentation and a classification using fuzzy membership vectors to detect the changes in the images observed at different dates. Consider two co-registered images of the same scene, and one image is supposed to have the class map of the scene at the observation time. The method performs the unsupervised segmentation and the fuzzy classification for the other image, and then detects the changes in the scene by examining the changes in the fuzzy membership vectors of the segmented regions in the classification procedure. The algorithm was evaluated with simulated images and then applied to a real scene of the Korean Peninsula using the KOMPSAT-l EOC images. In the expertments, the proposed method showed a great performance for detecting changes in land-cover.