• Journal of Korea Port Economic Association
• /
• v.21 no.1
• /
• pp.23-44
• /
• 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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2011.04a
• /
• pp.484-489
• /
• 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.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.1033-1038
• /
• 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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2013.04a
• /
• pp.340-346
• /
• 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.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.51
• /
• pp.441-464
• /
• 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.

• International Commerce and Information Review
• /
• v.15 no.1
• /
• pp.333-356
• /
• 2013

The main purpose of this article is to find out the determinants of usage and performance of the uTradeHub system in Korean SMEs. To achieve the purpose of the study, the research model and the hypotheses were developed based on the previous research on uTradeHub and e-Trade. And to test the research hypotheses, empirical survey was conducted to Korean SMEs which were using uTradeHub services. The results of the empirical analyses are as follows. First, among the external factors, intra-industry competition and transaction intensity were significant determinants of uTradeHub usage level. Secondly, among the internal factors, only CEO's support was found to be a significant determinant. Thirdly, among the IT related factors, IT infrastructure and IT training were positively related to uTradeHub usage level. Finally, the uTradeHub usage level was found to have positive effect both on financial and non-financial export performance of the Korean SMEs.

• Current Industrial and Technological Trends in Aerospace
• /
• v.8 no.1
• /
• pp.118-130
• /
• 2010

In this paper, it is described the current technology status of bearingless rotor hub system for helicopter which is one of major rotor hub system. First, the advantages and disadvantages of major helicopter rotor hub system are described and compared each other. 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. Furtherly, recent helicopters which adopt this bearingless rotor hub system are described and introduced.

• Korea Trade Review
• /
• v.44 no.6
• /
• pp.105-118
• /
• 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
• /
• 2008.06a
• /
• pp.232-237
• /
• 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.

• Journal of the Economic Geographical Society of Korea
• /
• v.12 no.4
• /
• pp.540-556
• /
• 2009

The hub and spoke network is a critical network-based infrastructure that is widely applied in current transportation and telecommunications systems, including Internets, air transportation networks and highway systems. This main idea of hub location models is to construct a network system which achieves the economy of scale of flows. The main purpose of this study is to introduce new hub location problems that take into account network reliability. Two standard models based on assignment schemes are proposed, and a minimum threshold model is provided as an extension in terms of hub network design. The reliability and interaction potentials of 15 nodes in the U.S. are used to examine model behaviors. According to the type of models and reliability, hubs, and minimum threshold levels, relationships among the flow economy of scale, network costs, and network resiliency are analyzed.