• International Journal of Aerospace System Engineering
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• v.6 no.1
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• pp.1-7
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• 2019

In the present study, structural safety and stability on the main wing and tail planes of the 1.2 ton WIG(Wing in Ground Effect) flight vehicle, which will be a high speed maritime transportation system for the next generation, was performed. The carbon-epoxy composite material was used in design of wing structure. The skin-spar with skin-stressed structural type was adopted for improvement of lightness and structural stability. As a design procedure for this study, the design load was estimated with maximum flight load. From static strength analysis results using finite element method of the commercial codes. From the stress analysis results of the main wing, it was confirmed that the upper skin structure between the second rib and the third rib was unstable for the buckling load. Therefore in order to solve this problem, three stiffeners at the buckled region were added. After design modification, even though the weight of the wing was a little bit heavier than the target weight, the structural safety and stability was satisfied for design requirements.

• Journal of the Korean Data and Information Science Society
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• v.19 no.4
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• pp.1233-1246
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• 2008

This study examines characteristics of people who are experiencing severe hair loss problems. We focus on how these characteristics are related to their psychological problems, hair loss treatments, wig-wearing practices, and life styles. We gathered survey data from people who visited wig shops for their hair loss problems. The study shows that men and women have different characteristics in every aspect we consider.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.8
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• pp.37-46
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• 2004

Several notes on ground effects drawn from Navier-Stokes analyses and their aerodynamic interpretations were addressed here; For two-dimensional ground effect, the change of surface pressure due to image vortex, the venturi effect due to thickness and the primary inviscid flow phenomena of ground effect, and for three-dimensional ground effect, strengthened wing tip vortices, increased effective span and the outward drift of trailing vortices. Irodov's criteria were evaluated to investigate the static longitudinal stability of conventional NACA 6409 and DHMTU 8-30 airfoils. The analysis results demonstrated superior static longitudinal stability of DHMTU 8-30 airfoil. The DHMTU airfoil has quite lower value of lrodov's criterion than the conventional NACA airfoil, which require much smaller tail volume to stabilize the whole WIG-craft at its design stage.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.5
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• pp.381-389
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• 2011

In this study, we are focusing our attention on lift characteristics of the low aspect wings for Wing-In Ground effect crafts (WIG). Experimental measurements at an open-type wind tunnel are carried out and results are comparatively presented. In order to simulate the realistic ground condition in where the WIG craft is flying, moving ground is implemented by a conveyor belt rotating with the same velocity of the inflow. We consider two different wings (NACA0012 and DHMTU section) which have four different aspect ratios (0.5, 1.0, 1.5 and 2.0). Forces acting on the wings are measured and lift characteristics are elaborately investigated for various different conditions. In addition, end-plate effects are estimated. Results are validated by comparing with theoretic solutions of the symmetric airfoil. Present results show that ground effects are differently generated in moving or fixed ground conditions, and hence left characteristics are affected by the ground condition. Consequently, accurate aerodynamic forces acting on the WIG craft are guaranteed in a realistic moving ground condition.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.179-184
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• 2005

In the present study, conceptual design of the main wing for 20 seats WIG{wing in Ground Effect) flight vehicle, which will be a high speed maritime transportation system for the next generation, was performed. The high stiffness and strength Carbon-Epoxy material was used for the major structure and the skin-spar with a foam sandwich structural type was adopted for improvement of lightness and structural stability. As a design procedure for this study, firstly the design load was estimated with maximum flight load, and then flanges of the front and the rear spar from major bending load and the skin structure and the webs of the spars were preliminarily sized using the netting rules and the rule of mixture. In order to investigate the structural safety and stability, stress analysis was performed by Finite Element Codes such as NASTRAN/PA TRAN[6] and NISA II [7]. From the stress analysis results, it was confirmed that the upper skin structure between the front spar and rear spar was very unstable for the buckling. Therefore in order to solve this problem, a middle spar and the foam sandwich structure at the upper skin and the web were added. After design modification, even thought the designed wing weight was a little bit heavier than the target wing weight, the structural safety and stability of the final design feature was confirmed. Moreover, in order to fix the wing structure at the fuselage, the insert bolt type structure with six high strength bolts was adopted for easy assembly and removal.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.7-12
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• 2007

Previously study on structural design of the main wing of the twenty-seat class WIG (Wing in Ground Effect) craft. In the final design, three spars construction was selected for safety in the critical flight load, and the Carbon-Epoxy material was selected for lightness and structural stability. In this study, the forced vibration analysis was performed on the composite main wing structure of the twenty-seat class WIG craft with two-stroke pusher type reciprocating engine. The vibration analysis based on the finite element method was performed using a commercial FEM code, MSC/NASTRAN. Excitations for the frequency response analysis were assumed as the Y-mode (lateral mode), the Z-mode (vertical mode) and the $M_{xyz}$-mode (twisted mode) which are typical main vibration modes of engine. And excitations for the transient response analysis were assumed as the X-mode (longitudinal mode) with the oscillating propeller thrust which occurs in operation.

• Journal of the Korean Society of Costume
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• v.60 no.5
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• pp.51-70
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• 2010

The ritual to change the hairstyle holds the same meaning as the coming of age ceremony. The ceremony was performed throughout three times including choga, jaega, and samga. The garment and hairstyle attuned to the ceremony formalities. Women in the royal family had 'su-siK when they were fully grown up during choga, 'gwang-sik' during Jaega, and 'keun-meo-ri (big hairstyle)' during samga. 'su-sik' is the noblest hairstyle according to social status, which is allowed to be worn only by spouse of king and prince, regardless of adult or not. During jaega, 'gwang-sik' which was 'u-yeo-meo-ri', is made by winding 'darae (wig)' around a jjok-jin-muri (bun) [Jo-jim-meo-ri]? which distinguished the hairstyle of unmarried women, who did not go through a coming of age ceremony yet. Unmarried women maintained a hairstyle which is mostly twisted into one string, but they had 'saeang-meo-ri' when they were prepared for ceremonial costumes. Also, they had 'ga-raemeo-ri' when growing further. keun-meo-ri during samga is an addition of keun-meo-ri chaebal(wig) onto u-yeo-meo-ri. Women in the royal family made geo-du-mi by adding keun-meo-ri, which is formed by twisting wig, and oimyeongbu (noble ladies) and sanggung (court ladies) added a wooden wig called u-yeo-mi. Also, yeoryeong wore ga-ri-ma. In this way, the types of hairstyles were distinguished according to hierarchy. As the coming of age ceremonial dress. Wonsam was worn. During choga. wonsam was worn as a formal dress and during jaega and samga wonsam was worn as a full dress.

• Journal of Industrial Convergence
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• v.20 no.6
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• pp.117-123
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• 2022

Appearance, which is directly related to competitiveness, has become one of the essential self-care for modern people living in the era of the 4th industrial revolution. For the purpose of producing more practical and convenient wigs for suffering customers, data of research subjects were collected through an information search portal site. The trend of new material development of leading wig companies was analyzed. As a result of the study, it was found that many applications for wig attachment and binding technology were applied before 2005, artificial hair-related manufacturing technology for wigs from 2006 to 2013, and functional-related wig technology after 2014. In addition, both H and M companies showed the development trend of new materials for shape memory materials and nanoskins with their own characteristics. We believe that this study will be provided as basic data for the development of functional wigs that can lead to customer satisfaction while providing customers with a comfortable and convenient fit in the wig industry market.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.2 s.152
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• pp.180-188
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• 2007

In this paper the longitudinal control problem for the large WIG(wing-in-ground effect) craft is considered in the sense of the control augmentation system(CAS) derived by control surface of elevator. In order to achieve longitudinally stable systems, two modes of CAS are applied to the control systems which are pitch rate hold mode and pitch hold mode for steady flight. Since the employed CASs include the dynamic properties of the actuator time delay and the low pass filter, it provides the possible solution to be applicable to real systems. Nonlinear model simulations are fulfilled to investigate the effectiveness of the applied CASs with wind disturbance.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.2
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• pp.192-197
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• 2008

The value of this paper is to use reduced size apparatuses to perform field measurement in order to identify and validate that the harmonic-current effects are due to the presence of self-excitation capacitance connected at stator's terminals of the studied SEIG. This paper has presented the measured electrical quantities of a three-phase $\Delta$-connected wind induction generator (WIG) under sudden connection and disconnection of resistive loads. An intelligent power-system recorder/monitor has been employed to measure three-phase voltages and currents of the studied system at the terminals of the studied WIG and the load. The measured electrical quantities have been analyzed. Total harmonic distortion (THD) of current using cumulative probability density function has been employed to determine the penetration of harmonic distortion at load side. The results show that the harmonic currents generated by the studied WIG can be severely amplified by the connected self-excited capacitance at the stator's terminals.