• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.7
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• pp.535-543
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• 2014

A computational simulation for a nonslender BWB UCAV configuration with rounded leading edge and span of 1.0m was performed to analyze its aerodynamic characteristics. The freestream is 50m/s over -4 to 26 degree A.o.A.s. Reynolds number based on the mean chord length is $1.25{\times}10^6$. 3D multi block hexahedral grids are used which allow good grid quality and ease to capture boundary layer. ${\gamma}-Re_{\theta}$ model as well as $k-{\omega}$ SST model is employed to assess the effect of transition for flow behavior. Drag and lift of the UCAV were well predicted while $C_M$ is under predicted at high angle of attacks and influenced by the turbulence models strongly. After assessing pressure distribution, skin friction lines and velocity field around the UCAV configuration, it was found that transition effect should be considered to enhance the prediction of aerodynamic behavior by a vortical flowfield.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.1
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• pp.87-97
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• 2010

Purpose: The purpose of this study is to investigate the effects of sports vision training on baseball player's visual performance and baseball records. Methods: All subjects were 21 males of high school baseball players, and they participated on eight weeks of sports vision training program. Pre- and post- test results were obtained for static and dynamic visual acuity, static and dynamic stereo acuity, distance and near phoria, fusional reserves, near point of convergence, contrast sensitivity, visual-reaction time. Results: Statical analysis indicated significant improvement in most of mentioned visual variables and baseball records (p<0.001). Conclusions: It can be concluded that the sports vision training program improves visual skills of baseball players, which could lead to improvement in the baseball records. Vison training will be a promotor for baseball player to enhance their performance if proper test instruments and training course is supplied.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.2
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• pp.17-24
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• 2003

This paper presents results from steady wind tunnel test conducted on a $65^{\circ}$ delta wing at a root chord Reynolds number of $1.76{\times}10^6$. In these experiments, the wing was instrumented with 188 pressure taps, conjunction with powerful multi-channel data logging system, allowed the wing upper surface pressure distribution to be measured. Analysis indicates that the wing upper surface distribution can provide considerable insight into the comvined aerodynamic effects of angle of attack and sideslip on the wing. In a sideslip condition, the strength of the vortex on the windward side is much stronger than that of leeward side. This asymmetric pressure disstribution betwwen each side of wings result in a negative value of rolling moment. However, at a certatin range of angle of attck and sideslip angle(${\alpha}$=$24^{\circ}{\sim}36^{\circ}C$, ${\beta}$=$-5^{\circ}{\sim}-15^{\circ}C$) abrupt change of sign of rolling monent, rolling monent reversal, was observed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.12
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• pp.1-8
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• 2005

A parametric study has been accomplished to figure out the effects of the elliptic cylinder thickness, angle of attack, and Reynolds number on the lift and drag forces exerted on the elliptic cylinder. A two-dimensional incompressible Navier-Stokes flow solver is developed using SIMPLER method to analyze the unsteady viscous flow over elliptic cylinder. Thickness-to-chord ratios of 0.2, 0.4, and 0.6 elliptic cylinders are simulated at different Reynolds numbers of 400 and 600, and angles of attack of $10^{\circ}$, $20^{\circ}$, and $30^{\circ}$. Through this study, it is observed that the elliptic cylinder thickness, angle of attack, and Reynolds number affect significantly not only the time-mean values and the amplitudes of the drag and lift forces but also the frequencies of the force oscillations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.11
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• pp.933-940
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• 2016

A comparative study between a wind tunnel test and an XFOIL simulation looking at the aerodynamic performance of the airfoil for MW-class wind turbine was conducted for validation in the design stage. Tests are carried out for 21% and 30% thickness-ratio airfoils developed for 5 ~ 10 MW offshore wind turbine and the results are compared with the output from the XFOIL simulation at Reynolds number $1.0{\times}10^7$. The test is performed at a free-stream velocity of 50 m/s, corresponding to a Reynolds number of $2.2{\times}10^6$ based on the chord. Surface roughness is simulated using a zig-zag tape. Discrepancies between the results of the test and the XFOIL analysis are found, however, meaningful data for surface pressure distribution, basic performance and surface roughness effect are obtained from the tests, while useful lift-to-drag ratio data is found by the XFOIL simulation.

• Korean journal of communication and information
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• v.26
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• pp.157-208
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• 2004

This study explored how television news constructed an issue of the building of a nuclear waste facility on Wido, an issue which displayed a social conflict in the latter half of the year 2003. To do this, this study conducted frame analysis on KBS and MBC main news including national and local ones, broadcasted from 11 July, 2003 to 10 December, 2003. It was found that television news tended to stress violent protests against site designation and social disorder rather than the causes of a conflict and its solutions. Therefore, news reporting excluded fundamental reasons of conflict such as the governmental decision-making process of site designation, geological suitability, safety issue and nuclear energy policy, emphasizing the confrontation and clash between pro and con groups of site designation. This indicates that television news defines an issue of the building of a nuclear waste facility as the local conflict between groups, the police and demonstrators, or neighbors who approve and protest the site designation, not as the national issue of nuclear policy.

• Korean journal of communication and information
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• v.80
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• pp.224-253
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• 2016

In this study, we analyzed the television news frames related to private school irregularities. Television broadcasting stations have not dealt with underlying problems of private school irregularities, but their reporting have been focused more on stating the situations. While Public announcing frame, Interference and solutions frame, Moral hazard frame and Protests and strikes frame have been applied in reporting, Autonomy highlighted frame and Publicity highlighted frame which are fundamental to the existence of private schools hardly appeared. In particular, the adhesion between private schools and political power has been continuously pointed out to be a cause of raising problems, whereas articles with such perspectives were hard to find. As a result, television broadcasting stations are required to change the way in reporting of private school irregularities in order for a lively discussion about them as the social agenda.

• Korean Journal of Social Welfare
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• v.66 no.2
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• pp.231-253
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• 2014

This paper aims to investigate epistemic principles and practical virtue items in Confucism about formation of social capital in a community. First, I have reviewed the basic perspective of Confucism utilizing holistic point of view, which is based on the theory of Yum-Yang, and human relationship in terms of role harmony, which is based on the theory of Si-Wi. I have then explored several items, some of which are Jung and Hwa as an internal value criterion, Ui and Ye as an external one. Analyzing other items such as In and Deok as directional items, Chung-Seo and Hyeol-ku-ji-do as epistemic items and Hyo and Ye as practical ones, I have found out that all of them, mentioned above functioned as factors of social capital in a community. Therefore, we emphasize that Confucian epistemic principles and practical virtue items can not only function as components of social capital in modern communities but have useful and practical implications for policy in modern community welfare.

• Korean journal of communication and information
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• v.54
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• pp.32-57
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• 2011

This study examined how the Korean courts have made a balance between rights of school teachers' expression and the public interests derived from regulating their rights for expression in related cases. Under the Korean laws such as National Public Service Law and the Law on Assembly and Demonstration, school teachers are considered as civil servants and basically not allowed to assemble to demonstrate for their own interests. The analysis revealed that in 24 cases from a total of 31 teacher-related court cases, teachers were found guilty in violation of related laws. In deciding whether the teachers' participation on anti-government assembly was guilty or not, the courts put an emphasis on public purpose of their expression, the degree to which their expressions affect the society, and specific contents of their expression. Conclusively, it was found out that in applying the related law, Korean courts tend to overweigh the public interests, rather than the teachers' right to express.

• The Journal of the Korea Contents Association
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• v.16 no.7
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• pp.154-167
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• 2016

This study is to analyze whether the use of SNS in politics has any political effects. Most previous studies on political participation by SNS tended to just focus on the participation difference between SNS users and non-users. The test results first show that the development of ICT increases citizens' interest in political information and differentiate the methods of their political participation. Second, we identified SNS users tend to have higher reliability in political information and greater transversion effects by the use of media. Finally, the study verifies SNS is a more effective tool in collective actions such as non-customary rallies and demonstration rather than in customary political participation.