• Journal of the Society of Naval Architects of Korea
• /
• v.36 no.2
• /
• pp.29-39
• /
• 1999

In this study, mathematical modelling for initial motion of test vehicle launched from sliding launcher is performed, and simulation results from this mathematical models are verified by comparing them with sea trial results. Especially, it is showed that models using strip method give better results than using empirical formulae and linear equations of motion. This mathematical model can give useful tools to design sliding launchers or test vehicles.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.34 no.9
• /
• pp.20-24
• /
• 2006

Wind tunnel tests were conducted to compare gliding and turning performance of normal cruciform parachutes with newly modified cruciform parachutes. Modified cruciform parachute has better gliding performance than original cruciform parachutes but, modified cruciform parachute has worse turning performance than original cruciform parachute.

• Atmosphere
• /
• v.8 no.2
• /
• pp.12-13
• /
• 1998

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.10
• /
• pp.927-934
• /
• 2011

Design parameter analysis is performed for a solar-powered UAV, storing potential energy by climb flight. Parameters related to the flight for saving potential energy, i.e. minimum & maximum altitudes for level flight, gliding & climbing angle, design point speed & altitude, gliding & climbing start time are investigated as design parameters. Weight and size of the UAV are determined using a weight model for the components of the solar-powered UAVs. Produced energy and consumed energy are calculated using these weight and size, yielding the required weight of the battery for a given mission. Relationship between the total weight of the UAV and each parameter is investigated. For the parameters listed above, there exist their ranges only where the design is possible. And there exist optimal values of these parameters minimizing the total weight.

• Digital Contents
• /
• no.12 s.115
• /
• pp.86-89
• /
• 2002

유선보다 빠른 무선시대가 도래할 것으로 보인다. 모든 케이블이 지상으로부터 사라지고 인터넷을 비롯한 각종 데이터 콘텐츠들이 2.4GHz 무선 비행을 시작해 11Mbps 고속 활강을 시도중이다. ADSL의 뒤를 이은 초고속 인터넷 서비스를 위한 무선 네트워크 시대의 개막으로 우리의 일상을 변화시킬 정보를 신혁명의 수해에 대한 기대가 벌써부터 뜨겁다. 최근 무선 LAN을 둘러싼 시장의 움직임과 향후 전망을 살펴본다.

• Journal of computational fluids engineering
• /
• v.21 no.3
• /
• pp.71-76
• /
• 2016

In speed skiing, aerodynamic forces play an important role in determining performance of the skier. To predict aerodynamic effects of the posture of the skier on alpine downhill skiing, we constructed equation of motion of the skier and performed the corresponding CFD simulations. Comparing drag and lift of three different skier postures, it has been shown that drag decreases significantly by tucking upper body to lower body and stretching arms forward. Also, aerodynamic lift which worked as downforce in standing posture worked upward in tuck posture, reducing friction force between snow and ski. This indicates that tuck posture have advantages over standing posture in dual mechanism, namely by reducing drag and also increasing lift. By this two-dimensional initial study we could reveal the general tendency of the aerodynamic force over the skier's body. This study not only provides a theoretical foundation for the athletes to understand the aerodynamic effects of skier postures but also shed a light on towards more accurate and rational three-dimensional CFD simulation of skiers in the near future study.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.05a
• /
• pp.320-322
• /
• 2021

With the development of wireless Internet technology and the expansion of the game market, various forms of games are being developed that are mounted on various platforms, including mobile platforms. In this environment, ensuring the immersion of the game user's perspective will secure the game's competitiveness, so it is necessary to increase the immersion by satisfying each area presented by the Human Computer Interaction (HCI) theory. To this end, this high school implemented downhill games and experimented with kiosks by applying an interface that recognizes the human body's movements as a way to secure freedom and immersion of game users.

• Journal of Korean Society of Forest Science
• /
• v.76 no.1
• /
• pp.17-26
• /
• 1987

To develop the rehabilitation measures for rockily denuded forest lands which are widely distributed in Seoul metropolitan area, erosional characteristics of denudation should, first of all, be evaluated and analysed. As a fundamental study for developing such technical measures, the rockily denuded lands were classified into 6 types according to denudation features of the mountain land, and also movements of stone debris-and-sand on rock-exposed hillslopes were measured and analysed. The 6 basic types of denudation features include a) natural rock-outcrop-exposed land, b) stone debris-and-sand scattered land, c) stone debris-and-sand deposited land, d) coarse sand producing bare land susceptible to weathering and erosion, e) dwarfed pine growing land, and f) torrential valley susceptible to the debris slides. In the stone debris-and-sand scattered hillslopes (type b), average amount of moved-down debris reached to about 3.9 ton/ha/yr due to surface washing and slidings. In the particle size distribution of the moved-down debris, it amounts to about 25% of 10-25mm, about 15% of 5-10mm, about 24% of 2-5mm, and about 36% of less than 2mm in diameter class, respectively. The detailed experimental studies should be accomplished further more about the denudation processes including weathering, erosion and debris slides on rock-exposed hillslopes.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1993.02a
• /
• pp.11-12
• /
• 1993

센서를 인간의 오감에 비유한다면 가속도센서는 시각, 청각, 촉각, 미각, 후각 중에서 어떤 감각기관인가\ulcorner 먼저 시각을 쉽게 생각할 수 있다. 시각기능은 거리, 위치, 형상에 민감하다. 그러나 이들의 시간에 다른 변화 즉 1차 미분량인 속도에는 어느정도 정성적으로 감응하나 2차 미분량인 가속도는 시각으로 판단하기 어렵다. 활강하는 스키선수나 써커스의 공중곡예가 시각에만 의존한다고 볼 수 없으며 이러한 로봇(robot)을 만든다고 할 때 가속도 센서의 중요성은 상상 할 수 있을 것이다. 움직이는 모든 시스템의 동적특성을 제어하기 위해 정교한 가속도센서는 필수적이다.

• The Science & Technology
• /
• v.32 no.9 s.364
• /
• pp.30-31
• /
• 1999

새로운 21세기에는 위락산업이 유명한 성장산업으로 떠오르게 된다. 한여름에도 활강을 즐길 수 있는 실내스키돔이 세워지고 원통모양의 '플라이어웨이 돔'에서 우주 비행복으로 갈아입은 뒤 200km의 돌풍을 타고 우주인처럼 유영을 즐길 수도 있게 된다. 2020년경에는 우주호텔이 등장하고 해저캠프촌도 건설된다. 또 아마존강에서 환경친화형 여행도 즐기고 에베레스트 등반 희망자도 줄을 잇게 된다.