• Title/Summary/Keyword: Center of Force

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The Activating Plan of Domestic Super-Highway Information Network Equipment Industry using Competitive Strategy Model (경쟁 전략 모형을 활용한 국내 초고속 정보통신 장비 산업 활성화 방안)

  • Ryu, Kyung-Suk;Park, Joo-Seok;Yun, Byung-Nam;Lee, Han-Gyu;Lee, Kwang-Jae
    • Information Systems Review
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    • v.4 no.2
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    • pp.323-341
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    • 2002
  • Due to the development of information technology, IT industry has become the core factor of a country competence. So we recognized the importance of information network technology as a basis of IT industry. The infrastructure and service in domestic super-highway information networks show the rapid growth both in quantity and quality because of the government programs. However, foreign information network equipment companies have most of the domestic market-share and have controlled core part of the industry, thus national companies are having a difficulty in penetrating the industry market. In this paper, we will analyze domestic super-highway information network equipment industry and make its activating plan using competitive strategy model.

A Study about the Training Program for the Kolman Technique on the Horizontal Bars (체조 철봉 콜만 기술동작의 훈련프로그램 적용 및 향상도평가)

  • Back, Jin-Ho;Park, Jong-Chul;Yoon, Chang-Sun
    • Korean Journal of Applied Biomechanics
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    • v.19 no.1
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    • pp.37-47
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    • 2009
  • This study develops a technique training program to enhance the completion of Kolman, the high air flight technique, and applies it to two national athletes of the horizontal bar, one of the gymnastic events, for eight weeks. After that, their improvement was measured through 3D motion analysis to help them elevate their performance. The training program includes swing, hand release, twist, and bar hold, and its implementation produced the results stated below. They were made to practice the motion in the following way. After the hand-standing of giant swing which initiates the motion, they lift their body upward a little bit more. Next, they take their body down almost like a vertical descent and make a deep tap swing. Instead of doing the tap swing which widens the flection of hip and shoulder joints, while body revolution is more emphasized in particular, they release the bar as raising the centroid of their body sufficiently. During the flight, they try to narrow every joint in their body. As a result, the bar's elasticity becomes greatly increased, and since the backing rate of their body gets higher, the centripetal force of the swing is improved that they can release the bar in the higher position. In addition, because they can erect their body faster during the flight, they can perform comfortable twist and revolution in the air. They can also adjust the direction of the flight easily without too much concern for the proper timing of hand release as they rise. Thereby, they can not only maintain adequate distance from the bar for the bar hold but also ensure enough distance for body revolution and twist.

Maternity, Suffrage, War, and State: A Diachronic Review of the Women's Movements in Modern Japan (모성·참정권·전쟁 그리고 국가 - 근대 일본 여성운동의 통시적 고찰)

  • Lee, Eun-Gyong
    • Cross-Cultural Studies
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    • v.43
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    • pp.79-113
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    • 2016
  • This study aims to diachronically explore the women's movements in modern Japan by focusing on three key words, 'maternity,' 'suffrage,' and 'war,' in uncovering how these concepts relate to Japan as a state. In particular, this study sheds light on the policies toward women not from the perspective of the state, but rather from women's perspective and evaluates their expectations toward the 'state' thorough the activities of Fusae Ichikawa and $Raich{\bar{o}}$ Hiratsuka. Hiratsuka, who was devoted to establishing the 'state protection of maternity,' ended up casting away such expectations toward the state after the failure of the petition movement developed by the New Women's Association. On the other hand, Ichikawa, encouraged by the success of women's suffrage movement in the U.S., remained active in the petition movement in the hope of attaining female suffrage. Because of this, Ichikawa was more vulnerable to the requests by the national authorities for the cooperation in war efforts-event though most of her activities were contained within the redressing of everyday life issues. The expectations toward the 'state' was a principal driving force of women's movements in modern Japan, yet at the same time it was also the reason why-as purging of Ichikawa symbolizes-they came to be stigmatized with the promotion of invasive war.

Design and Prototyping of Lifting Devices for Manhole Cover using Structural Analysis and 3D Printing (3D 프린팅과 구조해석을 이용한 맨홀의 부양장치 설계 및 제작)

  • Lee, Hyoungwook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.10
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    • pp.648-654
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    • 2018
  • In order to maintain manholes installed on the road, the manhole should be easy to open and close. Manhole covers under harsh conditions require that they can be lifted when attempting to open the manhole because the frame and cover are stuck and difficult to open and close. In this study, the design of a lifting mechanism was carried out to improve and integrate the locking type manhole. The mechanism of the locking manhole is that when the bolt located at the center is turned, the hub connected with the bolt descends, and the hook connected to the hub is rotated. The end of the hook is hooked to the manhole frame. The auxiliary device was installed on the hook so that the manhole cover can be lifted. The structure was designed to endure about 300kg of lifting force based on 70% of the yield stress of the hook to perform lifting function. The shape design was performed through the structural analysis using the finite element method. First, the basic design was performed with the simplified 2-dimensional model and the attachment position and shape were designed through the 3-dimensional model. In order to find out the structural problems of the designed shape, the scale downed model was fabricated through 3D printing and confirmed that the lifting function worked. Finally, it was confirmed that both the locking and the average lifting of about 6.1 mm can be done by applying the lifting mechanism through the machining and applying it to the existing locking manhole.

Numerical Study on Roughness Effect for Axi-symmetry Submerged Body in High Reynolds Number (고 레이놀즈 수에서의 축대칭 몰수체의 거칠기에 대한 수치연구)

  • Joung, Tae-Hwan;Song, Hyung-Do;Yum, Jong-Gil;Song, Seongjin;Park, Sunho
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.24 no.2
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    • pp.246-252
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    • 2018
  • In this paper, the friction drag force of 3D submerged body is investigated by considering the surface roughness, the first grid height, and the Reynolds number using open CFD source code, OpenFOAM 4.0. A procedure for estimating drag components by CFD code is set up and suggested in this study. In the 3D submerged body, because of the form factor in the 3D computations, the friction resistance with the small roughness of $12{\mu}m$ obtains different result with the smooth wall. As the Reynolds number increased, the boundary layer becomes thinner and the fiction resistance tends to decrease. In the computations for the effect of y+, the friction resistance and wall shear stress are excessively predicted when the y+ value deviates from the log layer. This is presumably because the boundary layer becomes thicker and the turbulence energy is excessively predicted in the nose due to the increase in y+ value. As the roughness increases, the boundary layer becomes thicker and the turbulence kinetic energy on the surface increases. From this study, the drag estimation method, considering the roughness by numerical analysis for ships or offshore structures, can be provided by using the suggested the y+ value and surface roughness with wall function.

Cultivation of millet in Mahan-Baekje Villages: Archaeobotanical examination of Osan site, Jangheung, Korea (전남 마한백제계 취락의 서속(黍粟) 재배와 농경 체계: 장흥 봉림리 오산유적 자료를 중심으로)

  • RYU Ara;KIM Sebin;OH Byungwook;KIM Minkoo
    • Korean Journal of Heritage: History & Science
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    • v.56 no.2
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    • pp.48-60
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    • 2023
  • Although foxtail and broomcorn millet have been cultivated since the Neolithic Age on the Korean Peninsula, there have been few studies on how the importance of millet cultivation changed over time. The discovery of millet has been rare in the Mahan-Baekje villages in the Jeonnam region, and archaeological discussions on ancient farming have centered around rice farming. However, a large amount of millet was found at the Osan site in Bongrim-ri, Jangheung, showing that the tradition of millet cultivation continued during the AD 3-4 centuries. In contrast to rice farming, which requires low-lying wetlands, hot and humid summers, and a large labor force, millet cultivation has few restrictions in terms of growing environment and labor mobilization. Regarding harvesting seasons, the crops at the Osan site can be divided into fall harvesting (rice, legumes, millet) and summer harvesting (wheat). Regarding field locations, the crops are divided into wetland crops (rice) and dryland crops (wheat, legumes, millet). The operation of the dual agricultural system contributed to subsistence resilience and agricultural production, making it possible to effectively manage social and climatic crises.

Study on the hydrophobic modification of zirconia surface for organic-inorganic hybrid coatings (유-무기 하이브리드 코팅액 제조를 위한 지르코니아 표면의 소수화 개질 연구)

  • Lee, Soo;Moon, Sung Jin;Park, Jung Ju
    • Journal of the Korean Applied Science and Technology
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    • v.34 no.2
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    • pp.260-270
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    • 2017
  • Zirconia has white color and physical, chemical stability, also using in high temperature materials and various industrial structural ceramics such as heat insulating materials and refractories due to their low thermal conductivity, excellent strength, toughness, and corrosion resistance. If hydrophobically modified zirconia is introduced into a hydrophobic acrylate coating solution, the hardness, chemical, electrical, and optical properties will be improved due to the better dispersibility of inorganic particle in organic coating media. Thus, we introduced $-CH_3$ group through silylation reaction using either trimethylchlorosilane(TMCS) or hexamethyldisilazane(HMDZ) on zirconia surface. The $Si-CH_3$ peaks derived from TMCS and HMDZ on hydrophobically modified zirconia surface was confirmed by FT-IR ATR spectroscopy, and introduction of silicon was confirmed by FE-SEM/EDS and ICP-AES. In addition, the sedimentation rate result in acrylate monomer of the modified zirconia showed the improved dispersibility. Comparison of the sizes of a pristine and the modified zirconia particles, which were clearly measured not by the normal microscope but by particle size analysis, provided a pulverizing was occurred by physical force during the silylation process. From the BET analysis data, the specific surface area of zirconia was approximately $18m^2/g$ and did not significantly change during modification process.

A numerical study on effects of drag coefficient of vehicle on jet fans in case of fire in road tunnels (도로터널 화재시 차량의 항력계수가 제연용 제연팬에 미치는 영향에 대한 해석적 연구)

  • Yoo, Yong-Ho;Yoo, Ji-Oh;Kim, Hyo Gyu
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.16 no.6
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    • pp.553-560
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    • 2014
  • The road tunnel install a vent for the purpose of ventilation and smoke control. Ventilation equipment capacity(number of jet fans) depends on from the condition that of the pressure and ventilation resistance. Pressure and the resistance under operating vehicle have affected on the drag coefficient. The drag coefficient of the tunnel have affected by the blockage effect and slipstream effects. However, when calculating the ventilation fan, are not properly consider taking into account such effects. Therefore, ventilation force may have been slightly overestimated. This paper describes the drag coefficient through a numerical analysis to calculate the equivalent resistance area that reflects the vehicle distance, and examined the equivalent resistance area. The ventilation coefficient corresponding to the result heavy vehicle mixing ratio of the present study was not clear. Equivalent resistance area had reduced by about 86% compared to the road design handbook current standards. Also it had analyzed and reduced to 62.2% compared to Korea Highway Corporation ventilation design criteria ratio, which is the old standard.

A Study of Structural Analysis Simulation for Squat Exercise Foot Plate (스쿼트운동장치의 풋플레이트 구조해석에 관한 연구)

  • Jung, Byung-Geun;Kim, Ji-won;Jeong, Byeong-Ho
    • Journal of the Korea Convergence Society
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    • v.8 no.9
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    • pp.365-372
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    • 2017
  • Squat exercise is one of the important free weight exercises that can safely and effectively expect the athletic performance by establishing the rationale. Therefore, it is necessary to study the side effects caused by incorrect exercise, scientific countermeasures and to develop a exercise estimation model. It is effective and accurate to use a variety of assistive devices to calibrate athletic posture. The issues of the structural analysis for designing a foot plate for squat exercise is to model the behavior by the dynamic behavior. It should be consider that the center of gravity of each segmented body is different when the maximum load is applied. It is applied to complete system design through simulation method with kinematic dynamic, ground reaction force and load analysis for the free weight exercise equipment, VR device, and safety foot plate. In this paper, the authors propose the design method for the vertical load distribution applied in the design of the foot plate used for the squat exercise mechanism, and based on these results, design make the more safe and reliable free weight exercise equipment system.

The research of the way to gain domestic and foreign market economy force of whitening cosmetics (미백화장품 국내외 시장경쟁력 확보방안 연구)

  • Park, Joon-su;kim, heung-gi
    • International Area Studies Review
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    • v.21 no.2
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    • pp.121-141
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    • 2017
  • The world whitening cosmetics market is fast being taken in 'complex functional cosmetics' including complex function. And highly functional cosmetics market that call cosmeceutical market is growing up with highly functional cosmetics market. In addition, natural cosmetics market including whitening function is growing up in the world in complex functional cosmetics. Distribution channel of the world functional cosmetics is digital communication through beauty and digital. Global companies are adding relationship in new space between customer and brand. So worldwide change phenomenon of whitening cosmetics distribution channel will suggest importance that it should be able to communication with customer in non-traditional space. Domestic whitening cosmetics market is decreasing to reference compound annual growth rate -3.61%. While complex type market is increasing to annual growth rate 33.28%. Since 2008, domestic whitening cosmetics market was changed in distribution channel of center of traditional door-to-door sales. Especially, online channel is about 1/6 level of offline, but since 2014, year-on-year increase rate of online showed 27.1%. In the future, it is anticipated that ratio of online sales is above offline. Whitening cosmetics distribution is being changed, and online channel is growing up, so domestic companies will need tragedy targeting new whitening cosmetics distribution channel and traditional offline channel at the same time. If new company go into whitening cosmetics market, the new company will have to consider natural cosmetics in complex functional cosmetics than whitening cosmetics market. To secure domestic competitiveness whitening cosmetics market, securing differentiation of brand or pursuing change of distribution channel, and we need to seek a method that company and customer can forge communication in new space.