• Journal of computational fluids engineering
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• v.1 no.1
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• pp.98-111
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• 1996

The compressible laminar and turbulent viscous flows on a slender body in supersonic speed as well as subsonic speed have been numerically simulated at high angle of attack. The steady and time-accurate compressible thin-layer Navier-Stokes code based on an implicit upwind-biased LU-SGS algorithm has been developed and specifically applied at angles of attack of 20, 30 and 40 dog, respectively. The modified eddy-viscosity turbulence model suggested by Degani and Schiff was used to simulate the case of turbulent flow. Any geometric asymmetry and numerical perturbation have not been intentionally or artificially imposed in the process of computation. The purely numerical results for laminar and turbulent cases, however, show clear asymmetric formation of vortices which were observed experimentally. Contrary to the subsonic results, the supersonic case shows the symmetric formation of vortices as indicated by the earlier experiments.

• 한국전산유체공학회:학술대회논문집
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• 1995.10a
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• pp.3-10
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• 1995

The compressible laminar and turbulent viscous flow on a slender body in supersonic speed as well as subsonic speed has been numerically simulated at high angle of attack. The steady and time-accurate compressible thin-layer Navier-Stokes code based on an implicit upwind-biased LU-SGS algorithm has been developed and specifically applied at angles of attack of 20, 30, 40 deg, respectively. The modified eddy-viscosity turbulence model suggested by Degani and Schiff was used to simulate the case of turbulent flow. Any geometric asymmetry and numerical perturbation have not been intentionally or artificially imposed in the process of computation. The purely numerical results for laminar and turbulent cases, however, show clear asymmetric formation of vortices which were observed experimentally. Contrary to the subsonic results, the supersonic case shows the symmetric formation of vortices as indicated by the earlier experiments.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.3
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• pp.33-45
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• 2007

The collision avoidance maneuver flight simulation for tilt rotor unmanned aerial vehicle was performed by time-accurate numerical integration method based on wind tunnel test data. Five representative collision avoidance maneuvers were simulated under constraints of aerodynamic stall, propulsion power, structural load, and control actuator capability. The collision avoidance performances of the maneuvers were compared by the computed collision avoidance times. The sensitivities of initial flight speed and collision zone shape on the collision avoidance time were investigated. From these results, it was found that the moderate pull-up turn maneuver defined using moderate pitch and maximum roll controls within simulation constraints is the most robust and efficient collision avoidance maneuver under the various flight speeds and collision object shapes in the tilt rotor UAV applications.

• 한국전산유체공학회:학술대회논문집
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• 2002.10a
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• pp.8-16
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• 2002

Now, the era of information, the rapid acquisition of vast and various information acts as a key role. for the national competitiveness. The smart UAV is brought to the fore as a new future technology which will be able to satisfy the information needs in broad and stereoscopic manner. The smart UAV, with VTOL capability, higher performance, and reliability over the existing technology thresholds, will lead the aerospace technology in the future. In this paper, the technology concept of smart UAV, the necessity of development, and the trend of worldwide R&D are introduced and analyzed. In addition, for the Smart UAV Development Program which is launched by the 21c Frontier R&D program this year, the role and application area of the CFD will be discussed.

• Korean journal of food and cookery science
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• v.24 no.2
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• pp.266-271
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• 2008

In this study, Jeolpyon(imprinted with flow patterns) was prepared with different amount of added Astragalus membranaceu extracts(0%, 3%, 6%, 9% and l2%)and then the quality and sensory characteristic effects were examined. All togather the chemical composition of the samples was as follows: $53.l2{\pm}0.04%$ of moisture, $l4.43{\pm}0.05$ crude protein, $7.6l{\pm}0.11%$ crude fat, and $21.35{\pm}0.09%$ crude ash. Hardness and cohesiveness significantly increased(p <0.001), and springiness, chewiness and adhesiveness decreased, with increasing amounts of Astragalus membranaceus extract. In the chromaticity analysis, the L-value(brightness)significantly decreased with increasing Astragalus membranaceus extract content, and the b-value(yellowness) increased in direct proportion to the extract content. Finally, in the sensory evaluation, the Jeolpyon containing 9.0% extract received the highest overall preference scores.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.05a
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• pp.4-4
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• 2003

Various Cu films were fabricated using sputtering and electroplating with and without additive, and their surface damages after annealing were investigated. After annealing at 43SoC, the difference between damage morphologies of the films was observed. In some films stress-induced grooves along the grain boundaries were observed, while in the others voids at the grain boundary triple junctions were observed. It was also observed that the stress-induced groove was formed along the high energy grain boundaries. It was found out that the difference of the morphologies of surface damages in Cu films depends on not process type but grain boundary characteristics. To explain the morphological difference of surface damages, a simple parameter considering the contributions of grain structures and grain boundary characteristics to surface and grain boundary diffusions is suggested. The effective grain boundary area, which is a function of grain size, film thickness and the fraction of high energy grain boundaries, played a key role in the morphological difference.

• Journal of Korean Dental Hygiene Science
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• v.3 no.2
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• pp.59-66
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• 2020

Dental hygienists handle periodontal tissue every day. Since periodontal tissue contains hard and soft tissue, dental hygienists need to cultivate scientific knowledge about bone tissue. This study introduces recent research results on cells and cytokines related to bone tissue. Recently, bisphosphonate-related osteonecrosis of the jaw has been reported, therefore we would like to present osteoporosis and osteoporosis treatment drugs and their side effects in this study.

• The Journal of the Acoustical Society of Korea
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• v.21 no.1
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• pp.69-72
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• 2002

We propose a modified splitting method to obtain an initial codebook, which is used to design a codebook. The principle of the proposed method is that the more representative vectors are assigned to the class, which has the mere member training vectors or a lower squared error. The conventional K-means algorithm and the method provided from reference (5) are used to estimate the performance of the designed codebook. In thin work, the proposed method shows better results than the conventional splitting method in all experiments.

• Proceedings of KOSOMES biannual meeting
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• 2009.06a
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• pp.165-165
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• 2009

• Journal of the Korean Society for Precision Engineering
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• v.20 no.10
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• pp.156-163
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• 2003

This research presents modeling of a functional surface which is a constructed free-formed surface. The modeling introduced in this paper adopts modified B-spline that is utilizing approximating technique. The modified B-Spline is constructed with altered control vertices. It is applied to measure points on a surface of an impeller blade. This research builds a surface-modeler accepting inputs of measured points. Generation of cutter-paths for NC machining employs the model of the constructed surfaces. The machined surfaces which is generated in several cases are compared in the aspect of machining accuracy.