• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.11
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• pp.1039-1048
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• 2008

new computational procedure for the Non-Linear Vortex Lattice Method (NLVLM) is suggested in this work. Conventional procedures suggested so far usually involves inner iteration loop to update free vortex shape and an under-relaxation based iteration loop to determine the free vortex shape. In this present work, we suggest a new formula based on quasi-steady concept to fix free vortex shape which eliminates the need for inner iteration loop. Further, the ensemble averaging of the induced velocities for a given free vortex segment evaluated at each iteration significantly improves the convergence property of the algorithm without resorting to the under-relaxation technique. Numerical experiments over several low aspect ratio wings are carried out to obtain optimal empirical parameters such as the length of the free vortex segment, the vortex core radius, and the rolled-up wake length.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.5
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• pp.397-403
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• 2007

Insect and birds in nature flap their wings to generate fluid dynamic forces that are required for locomotion. To develop a feasible flapping MAV, it is of crucially important to study the fundamental relations between flapping motion and thrust generation. In this paper, the onset conditions of the thrust generation of a heaving flat plate is investigated using a Lattice-Boltzmann method. For a fixed heaving amplitude of h/C=0.5, the effect of reduced frequency on the thrust generation is investigated. For several values of heaving amplitude(h/C=0.25, 0.325, 0.50), the effect of reduced frequency on the thrust generation is also investigated. It can be said that Strouhal number is more important rather than reduced frequency in case of thrust generation. It is found that the critical Strouhal number over which the flat plate starts to produce thrust is around 0.1. Thrust is an exponential function of the Strouhal number.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.3
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• pp.259-267
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• 2017

Flow fields around a KARI-11-180 airfoil, SDM and transonic body are numerically simulated by using an unstructured meshes based compressible flow solver developed at KAIST. RANS equations are solved to analyse the flow fields and Roe's FDS method is adopted to evaluate convective fluxes. Turbulence effect of the flow fields is modeled by a SA model, SST model and ${\gamma}-{\widetilde{Re}}_{{\theta}t}$ model. It is found that smaller drag coefficients are predicted for the KARI-11-180 airfoil when a transition phenomenon is considered and small deviations exist between CFD and EFD results. For the SDM, flow separation is observed at a leading edge and calculated aerodynamic properties show similar tendencies to experimental results. A shock wave on main wings of the transonic body is successfully captured by the present flow solver at a Mach number 0.9. Estimated pressure profiles by means of the present CFD method also agree well with those of wind tunnel results.

• Journal of the Korean Society of Costume
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• v.37
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• pp.47-69
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• 1998

The purpose of this study is to inquire the hair, head-dress and clothing(upper clothing: Veil, Samkaksika, Sash) of Bodhisattvas in Dunhuang Mogaoku of the period from Northern Liang Dynasty(421∼439) to Tang Dynasty(618∼907). The method of this figure and the change of clothing form : 'Dunhuang Mogaoku'1st Volume-4th Volume. The Bodhisattvas' hair style are somehat various ; A part in her hair, Suibal, Gae, Sakbal. A part in Bodhisattvas's hair is observed from Northern Liang Dynasty to Sui Dynasty. But Suibal had been continuous succeeded. Meanwhile, in the periods of Sui and Tand Dynasty, there were the hair styles whose ends were curled up. It is called Eulle Meor-ee. Especially, in Tang Dynasty various styles of Gae were appeared. Doogun was observed from Northern Wei to Tang Dynasty. There were three kinds of head-dress; Samsikkwan(having 3 decoration), Bokwan and Jungmeunkwan(appeared in Tang Dynasty). Meanwhile, Sash let was become more and more decorative. The Upper clothing can be classify into Veil, Samkaksika, Sash, etc. Veil were observed in every period but X shaped one was form Northern Wei and U shaped one was from Northern Zhou Dynasty. After the period of Sui Dynasty U shaped Veil become prevalent. Samkaksika was observed for the first time in Northern Zhou Dynasty. Cutted sam-kaksika was appeared in Sui Dynasty and succeeded to Tang Dynasty. Poncho tyed Samkaksika was also observed in Tang Dynasty. In Westhern Wei Dynasty. daesupo was used into outter garment, which us that chinese influence was deep tell. Sash showed up in Tang Dynasty and it is used for Veil for the whole period of the Dynasty. But using sash for veil was formally hanged on going the lated period of Tang Dynasty. We can observe the sun-moon decoration and the wings of a bird decoration at the Bokwan, Veil, Samkaksika and Sash, etc. It is was the influendce of Sasan Per-sia and India. I will fill up the insufficency of this study wity continous research of ornament(Muktahara) and skirt of Bodhisattva and deeper inquiry of the relationship around the many countries.

• Journal of the Korean Society of Costume
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• v.25
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• pp.183-199
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• 1995

Among many different approaches of study of history of Kokuryo clothing culture, this study attempted to understand the costume by including political , militarial , economical , cultural , and religious aspects of Kokuryo society. It also included pictures in mural tumbs and old studies in Kokuryo costume. Clothing culture related to political life clearly differenciated social status by restricting styles and colors of clothes according to peoples social status. Generally people in high social status wore clothes with detailed decorations invariety of colors, and also used more fabrics than people in low social status. Costume was also affected by military life style that needed to meet the vigorous physical activities. High rank worriors wore iron scaled shielded clothes with red decoration on it which identified different ranks of the worriors. Economy also contributed it role to affect the clothing styles in Kokuryo. Based on old studies of costume, this study focused on people's life styles that included hunting and weaving . Hunting clothes were differentiated by decorating wit feathers . Jowoguan(조우관) is one of the examples. Since weaving was a major economic power or factor, silk and flax were very popular. People even used those fabrics to pay tax. Regarding cultural aspect , this study emphasized on song and dance wear along with active wear. Song and dance wear specially decorated with poka dots, however men and women wear were claryly distinguished. Unlike other clothes that were restricted in colors and styles, song and dance wear were decorated in variety of colors. Lastly this study presents religious aspects of Kokuryo costume . Monks wore black clothing (내의) that was influenced from China and the Western Regions(서역). To emphasize their religious power, Gods in the pictures of mural tumbs wore clothes with wings and feathers. God of fire and agriculture wore simple dresses without much decorations which represented simple life style of working class.

• Journal of the Korean Society of Costume
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• v.25
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• pp.185-199
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• 1995

Among many different approches of study of history of Kokuryo clothing culture, this study attempted to understand the costume by in-cluding political, militarial, economical, cul-tural, and religious aspects of Kokuryo society. It also included pictures in mural tumbs and old studies in Kokuryo costume. Clothing culture related to political life clearly differenciated social status by restricting styles and colors of clothes accord-ing to peoples social status. Generally people in high social status wore clothes with detailed decorations in variety of colors, and also used more fabrics than people in low social status. Costume was also affected by military life style that needed to meet the vigorous physi-cal activities. High rank worriors wore iron scaled shielded clothes with red decoration on it which identified different ranks of the worriors. Economy also contributed its role to affect the clothing styles in Kokuryo. Baseed on old studies of costume, this study focused on people's life styles that included hunting and weaving. Hunting clothes were differentiated by decorating with feathers. Jowoguan is one of the exemples. Since weaving was a major economic power or factor, silk and flax were very popular. People even used those fabrics to pay tax. Regarding cultural aspect, this study emphasized on song and dance wear along with active wear. Song and dance wear specially decorated with poka dots, however means and womens wear were claryly dis-tinguished. Unlike other clothes that were re-stricted in colors and styles, song and dance wear were decorated in variety of colors. Lastly this study presents religious aspects of Kokuryo costume. Monks wore black cloth-ing that was influenced from China and the Western Regions. To emphasize their religious power. Gods in the pictures of mural tumbs wore clothes with wings and feathers. God of five and agriculture wore simple dresses without much decorations which represented simple life style of working class.

• Fashion & Textile Research Journal
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• v.17 no.3
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• pp.429-439
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• 2015

This study develops a new brassiere for new silver women. A new brassiere design was developed for the silver generation based on apreliminary survey; subsequently, a wire and no-wire type of brassier were developed after a second fitting evaluation. The results were as follows. First, in terms of brassiere design, the cup shape was designed as mold type full cup, shoulder straps were designed as camisole type with cups, bias tape was designed for body correction in the side line and mash tape was designed for easy movement below the cups. On the other side ofthe cup shape was a pocketdesigned on a support pad forthe wire type and a support panel to serve as a wire in the no-wire type brassiere. Second, brassiere patterns were designed by referencing the educational H pattern. Thetotal length was elongated by 5cmto reduce pressure when wearing a brassiere and the height of the front center increased by 8cm for the stability of the front center of the brassiere. In addition, the side line was moved back by 3cm and the width of the brassiere wings was designed widely at 10.5cm. Third, a wearing test was conducted for the wire type and the no-wire type brassiere with comparison products, using a 7-point Likert scale. Appearance results and movement tests for the wire and no-wire type showed a higher score than comparison products.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.201-204
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• 2002

This paper describes the hydrodynamic characteristics of a test-bed AUV SNUUV-I constructed at Seoul National University. The main purpose of the AUV is to carry out fundamental control and hydrodynamic experiments. Its configuration is basically a long cylinder of 1.35m in length and 0.25m in diameter with delta-type wings near its rear end. On the edge of each wing, a thruster of 1/4HP is mounted, which is used for both drive and turn the vehicle for horizontal movement as the output control power is varied. A pair of control surfaces installed near its font part generates pitch moments for vertical movement. The 6 DOF mathematical model of SNUUV-I contains hydrodynamic forces and moments expressed in terms of a set of hydrodynamic coefficients. These coefficients can be classified into linear damping coefficients, linear inertial coefficients and nonlinear damping coefficients. It is important to estimate the exact value of these coefficients to control the vehicle precisely. Among these, the linear coefficients are known to affect the motion of the vehicle dominantly. The linear damping coefficients are estimated by using Extended Kalman Filter. The responses of the vehicle to input signals are used to estimate the hydrodynamic coefficients, which can be inferred from output signals measured from an IMU (inertial motion unit) sensor, while the linear inertial coefficients are calculated by a potential code. By using these coefficients estimated as described above, a simulation program is constructed using Matlab.

• Transactions of the KSME C: Technology and Education
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• v.2 no.1
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• pp.29-37
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• 2014

In this study, analyzed the aerodynamic characteristics of Kline-Fogleman airfoils and wings with those more efficiency at low Reynolds number. It was found that lift to drag ratio is enhanced in the range of Reynolds number below $2.4{\times}10^5$, especially, can be improved up to 26% at Reynolds number is $1{\times}10^4$. It was confirmed that the most advantage case in terms of lift-to-drag ratio is Middle case and lift-to-drag ratio is improved to 20% at 80% of the wing area is Kline-Folgeman airfoil. At this time, endurance time increase to 12%. Also taking the structural stability of the wing and lift-to-drag improvement into account, designed to be from 50% to 80% the size of the Kline-Fogleman Airfoil would be advantageous.

• Journal of the Korean Society for Library and Information Science
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• v.36 no.2
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• pp.243-264
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• 2002

In literature, it has been widely accepted that knowledge management (KM) success ratio in private companies depends on the corporate size and type of industries. However, there are few studies concerning the procedures about building knowledge management system in state-run corporations. Especially. as the Korean Government advocated the slogan saying. The Strong Nation with Knowledge and Information, the need to investigate the knowledge management case about state-run corporations instead of private companies becomes more urgent. In this respect, this paper is aimed at introducing how knowledge management system has been successfully incorporated in KAMCO, and summarizing several fact findings which are deemed noteworthy for other similar studies.