• 한국항만경제학회지
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• 제21권1호
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• pp.23-44
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• 2005

The port environment is rapidly changing in North-East Asia. Containerships are getting larger and faster and major shipping companies are converting to Hub & Spoke port networks on the transport systems. Therefore, the main ports in North-East Asia are intensively competing with each other for hub port. In terms of geopolitical position, locational conditions and external reputation of ports, Busan and Kwangyang ports have a comparative advantage in comparison with main ports in other countries. But in terms of weight of transshipment cargos in total container cargos, the quality of infrastructure in ports, the environment of logistics service and the cost of, using ports, Busan and Kwangyang ports have a comparative disadvantage. For the growth into hub port in North-East Asia, it is necessary that Busan and Kwangyang ports improve their weakness. Besides It is necessary to develope ports and hinterland quickly, offer uniformity of foreign investment laws and incentive systems.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.484-489
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• 2011

In this paper, it was described the current technology status of bearingless rotor hub system for helicopter which is one of major rotor hub system. Also, a conceptual study on the new bearingless rotor hub system of helicopter was described. First, the advantages and disadvantages of major helicopter rotor hub system are described in comparison to each other types of rotor hub system. The unique characteristics of bearingless rotor hub system are described compared to other types of rotor hub systems. Next, the main function, role and characteristics of the sub-components of bearingless rotor hub system are described. Recent helicopters which adopt this bearingless rotor hub system are described and introduced. This conceptual study shows that double-H sectional construction and rectangular construction of flexbeam are the most effective candidates of this new bearingless rotor system. This bearingless rotor hub system can be used for 7,000lbs class helicopter. Now, a further trade-off study will show.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1033-1038
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• 2003

A wind turbine obtains its power input by converting the force of the wind into a torque (turning force) acting on the rotor blades. The amount of energy which the wind transfers to the rotor depends on the density of the air, the rotor area, and the wind speed. Because it has long term operating life and very complex load condition, the fatigue strength of each component must be considered. In this paper, we calculated the load condition by wind using a combined blade elemental theory and a FEM based analytical approach was use to evaluate the fatigue strength of a Hub of wind turbine. The effect of tensile mean stress was taken into account by the modified Goodman diagram. Using this approaches, we evaluated the fatigue strength of hub and main shaft and improved the design.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.340-346
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• 2013

This paper describes a helicopter vibration induced by main rotor in forward flight. The hub loads in the fixed frame, which are dominant source of helicopter vibration, are obtained by multi-blade summation of rotating blades loadings. The components of 3/rev, 4/rev, and 5/rev blades loadings are transmitted by blades to 4/rev hub loads in the fixed frame. The vertical vibrations of helicopter at pilot seat and copilot seat are calculated through rigid body transfer functions considering airframe to be rigid body. The blades are assumed to be elastic and undergo the flap, lag, and torsion motion and free wake aerodynamic model is used to calculate the precise blade loadings in the analysis. The 4/rev vertical vibration responses are analyzed from rotating blade loadings and fixed hub loadings.

• 무역상무연구
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• 제51권
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• pp.441-464
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• 2011

It is childhood yet in uTradeHub system practical use. According as company's necessity of cost-saving is increased according to trade terms aggravation such as uncertainty of international money market, commodities prices rise, necessity of e-trade practical use in company is increased. Use is inevitable by state that link with e-Nego and e-B/L service with related presentation e-L/C banks is not made. At the present users are doing specification only service this main point, and practical use activation through public information and marketing about service is needed situation because most of, companies which is not using service, do not know about existence availability of uTradeHub system, usage, availability. This study presented five such as early materialization of user center's link and integration, medium and small enterprises e-trade participation extension, utilization ratio raising through government's public information, e-trade cooperation business activation between the country, electronic documents standardization etc. by prompting competition about practical use of uTradeHub system.

• 통상정보연구
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• 제15권1호
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• pp.333-356
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• 2013

본 연구는 uTradeHub시스템의 정식운영이 개시된 후 일정한 기간이 경과한 시점에서 uTradeHub시스템 활용실태를 분석하고, 다수의 표본기업들을 선정하여 이들에 대한 설문조사를 통해 우리나라 중소기업들이 uTradeHub시스템을 활용하는데 영향을 미치는 요인이 무엇인지를 파악하고자 한다. 이러한 활용요인과 uTradeHub시스템의 활용수준 및 성과의 인과관계를 검증함으로써 중소기업의 특성에 맞는 글로벌 전자무역의 활용전략과 이를 발전시키기 위한 협력 방안을 제시하는 것이 본 연구의 궁극적인 목적이다. 이러한 연구 목적을 달성하기 위해서 uTradeHub시스템을 이용하고 있는 회원 중소기업들을 대상으로 설문조사를 통해 실증분석을 한 결과 uTradeHub시스템의 활용 요인 중 기업외부요인으로는 산업내 경쟁강도와 거래강도, 기업내부요인으로는 최고경영자의 지원, 정보화 요인으로는 기업의 IT인프라와 정보화 훈련정도 등이 uTradeHub의 활용에 정의 영향을 미치는 것으로 나타났다. 또한 uTradeHub시스템의 활용도는 전자무역의 재무적 성과와 비재무적 성과에 유의한 정의 영향을 미치는 것으로 나타났다.

• 항공우주산업기술동향
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• 제8권1호
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• pp.118-130
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• 2010

본 논문에서는 헬리콥터 로터 허브 시스템 중 최신의 기술이 적용된 무베어링 허브 시스템에 대하여 적용된 기술에 대한 동향을 기술하였다. 먼저 헬리콥터 로터 허브시스템의 형태별 장단점을 분석하였으며, 무베어링 로터 허브 시스템이 타 허브 시스템에 비하여 갖는 고유의 특징에 대하여 기술하였다. 다음으로 무베어링 로터 허브 시스템의 주요 구성품에 대한 기능 및 역할, 특성에 대하여 기술하였다. 나아가 무베어링 로터 허브를 적용하고 있는 기 개발된 헬리콥터들의 사례에 대하여 기술하였다.

• 무역학회지
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• 제44권6호
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• pp.105-118
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• 2019

In the past two decades, due to the rapid fluctuations in the oil supply and demand in Northeast Asia as well as a surge in oil prices in the early 2000s, Korea has been developing the Northeast Asia Oil Hub project as a national project. This project was promoted based on the policy consideration that the nation's energy security and regional development can be promoted by establishing an oil hub in Northeast Asia that can eventually replace Singapore as East Asia's oil logistics hub. Following the construction of a large-scale oil storage facility in Yeosu in 2013, the main project in Ulsan has suffered many difficulties due to environmental changes such as the supply and demand of oil and political factors. The survey, which investigated the performance, problems, and prospects of the oil hub project, illustrates that scores of all sectors are of average level. In terms of performance and prospects, policies such as facility investment, law, and system improvement were determined to be rather high while operational areas such as value-added activities, profitability, and marketing activities were perceived as having more serious problems by respondents. In conclusion, despite the strong potential of Korea's oil hub based on its geographical location, facilities, and oil product capacity, there are problems related to policies, institutions, and investment. In the future, the oil hub business should be reviewed by considering environmental factors, and a drastic improvement plan for attracting foreign investors and oil traders should be established.

• 한국경영정보학회:학술대회논문집
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• 한국경영정보학회 2008년도 춘계학술대회
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• pp.232-237
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• 2008

Korea is one of the most advanced countries in terms of nation-wide readiness for conducting complex trade processes in an electronic way. Since various trade processes are well-known for their complexity and cost as well as time consuming characteristics due to required collaborations with involving parties, automation and efficiency are always the main concern of trade-related practitioners. Using information technology can be a possible solution to this problem and Korea has developed the national e-trade infrastructure called "u-Trade Hub." In this paper, we propose the framework to enhance the national integrated e-trade system called "u-Trade Hub," which is ready to be released for commercial use in near future. We propose the framework to upgrade u-Trade Hub in four directions: (1) opening, (2) strengthening community feature, (3) modularization, (4) seeking profitability. In this paper, we study and compare national e-trade environment of other countries such as Singapore and Japan. Then, we analyze and design the enhanced e-trade infrastructure based on Web 2.0.

• 한국경제지리학회지
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• 제12권4호
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• pp.540-556
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• 2009

허브-스포크 망은 항공, 육상 교통 및 정보통신분야에서 유동의 규모의 경제를 고려하여 기간망을 설계하는 대표적인 입지 최적화 문제이다. 이 연구는 우선, 기존의 허브 스포크 망에 관한 지리학 및 타 분야의 연구 경향과 함께 최근 논의되고 있는 신뢰성에 기반한 허브 입지 모델을 소개한다. 기본 모델은 입지 배분 방식에 따라 단일 배분 및 다중 배분 입지 모델로 구분되고, 기본 모델의 확장 형태로서 최소 유동량 제약을 적용한 입지 디자인 모델이 제시되었다. 모델의 행태를 살펴보기 위해 미국의 15개 도시의 신뢰성 및 유동 자료를 이용하여 네트워크의 규모의 경제성과 네트워크 비용, 그리고 신뢰성간의 관계에 초점을 두어 분석을 하였다. 이 연구는 경제성과 신뢰성에 바탕을 둔 입지 문제 및 네트워크 최적화 분야에 고려해야 할 요인의 특성을 밝혔다는 점에서 그 중요성이 강조된다.