• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.3
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• pp.99-104
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• 2015

As riders do not sense damage to hub bearings due to the friction that occurs while riding, unexpected accidents can happen. Hub bearings can also be broken by cracks due to minor impact. Therefore, the vibration analysis of bike hub bearings is thought to be important. Two bike hub bearings were modelled in this study. The bolts at both ends of the bearings were fixed. The standard weight of a Korean man was assumed to be 70Kg, and a force of 700N was applied. As a result of this study, maximum deformations occurred in bolts at both ends of the central axis. Regarding displacement due to natural frequencies, Model 2 had less deformation than Model 1. Using the results of this study, the structural safety of the design of hub bearings can be estimated, and design plans for durable hub bearings can be suggested.

• Aerospace Engineering and Technology
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• v.11 no.1
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• pp.19-26
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• 2012

The requirement for the aerodynamic hub drag, allocated from the system requirement of development of a bearingless rotor hub, was analyzed and embodied to be substantiated by the methodology assigned from the requirement. Drag prediction for the initial hub configuration was carried out by hand calculation using aerodynamic drag coefficients and the design change about the sectional shape of torque tube was suggested to satisfy the requirement. Finally, drag prediction was performed for the changed hub configuration by using unstructured overset mesh technique and parallel computation and the calculated result satisfied the requirement of the aerodynamic hub drag. It was found that the drag of final hub configuration was also within the range of drag inferred from the trendline of developed helicopter.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.663-669
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• 2005

Performance characteristics of an axial flow fan having distorted inlet flow have been investigated using numerical analysis as well as experiment. Two kinds of hub-cap, round shape and right-angled front shape, are tested to investigate the effect of inlet flow distortion on the fan performance. In case of right-angled front shape, axisymmetric distorted inflow is induced by flow separation at the sharp edge of hub-cap, and the characteristics of the inflow depends on the distance between hub-cap and blade leading edge. Flow analysis of the blade passage is peformed by solving the three-dimensional Reynolds-averaged Navier-Stokes equations. numerical solutions are validated in comparison with experimental data measured by a five-hole probe downstream of the fan rotor. It is found from the numerical results that non-uniform axial inlet velocity profile near the hub results in the change of inlet flowangle. The changed inlet flow angle near the hub invokesa flow separation on the blade surfaces, thus deteriorating the fan efficiency. The effect of the distance between hub-cap and blade leading edge on the efficiency is also discussed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.8
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• pp.655-661
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• 2012

In this study, aerodynamic drag of a bearingless rotor hub was predicted by computational fluid dynamics methodology using unstructured overset mixed meshes. The calculated results showed that the drag due to pressure forces rather than the viscous drag act as a major factor on both the fuselage and rotor hub, and the drag acting on the torque tube accounted for the largest portion in the hub drag. It was also found the hub drag accounted for 39 ~ 41% of the fuselage drag. Finally, the result confirmed the drag of the designed rotor hub satisfied the requirement of the aerodynamic hub drag by comparing with the drag trend of developed helicopter.

• Korea Trade Review
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• v.44 no.6
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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.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.59.3-60
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• 2020

We present the results of polarization observations at submillimeter wavelengths towards Monoceros R2 (Mon R2). The polarized thermal dust emission was obtained from SCUBA-2/POL-2 at 450 ㎛ and 850 ㎛, simultaneously. This observation is a part of the JCMT BISTRO survey project. The polarization angle distributions at 450 ㎛ and 850 ㎛ are similar and the mean value of angle differences at two wavelengths is 5.5 degrees. The Mon R2 is one of massive star-forming regions containing a clear hub-filamentary structure. The hub region shows star formation activities, and surrounding filaments provide channels for matters to move into the hub region. It is not well known the role of magnetic fields in a hub-filamentary structure. Some studies have shown well-ordered polarization segments along a filamentary structure and magnetic field morphology traced by polarization segments is interpreted as to help gas flow along the filamentary structrue. Our observations shows that filaments in Mon R2 have spiral structure and the magnetic field lines are parallel to the filaments. We interpret that the spiral structure can be formed by a rotation hub-filament system with gas flowing along the filaments to the hub. We found several dust clumps at the central part of the hub region of the Mon R2. They seems to be formed at locations where spiral field lines meet each other. These results show one observational example that a magnetic field play a role in gas flow.

• The Korean Journal of Air & Space Law and Policy
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• v.5
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• pp.303-320
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• 1993

The construction of New Seoul International Airport is under way despite much controversy. Among much discussed, but not well-formulated controversy is the possibility of the airport as a hub in the North Asia Region. This paper specifies the factors which render it possible for an airport to be a regional hub. Then each factor is applied to the new airport to see whether it can function as a hub airport. Also examined is the qualitative cost and benefit calculation related to the hub function. The usual discussion has missed one big point of cost side of hub function in the belief that the hub only produces benefits to the national economy where the airline and airport industry belong; earlier-than-expected congestion and the necessity to expand the airport sufficiently enough to accommodate the increasing air demand. An airport as a hub is determined by several factors; geographical location ; economic status of the country where the airport belongs ; bilateral air service agreements according to which the airlines can exercise the route rights; the airport charges which directly influence the cost structure of the carriers ; international aviation and airport related policies of each country in the region ; airport capacity etc. The tentative implications of this paper are the followings; first, the new airport is able to function as a regional hub in the transpacific routes which connect Asian countries and North America. That is, directional hubbing by the airlines is implicated; second, the main benefits may be accrued to american airlines exercising all the route rights in the Asian region; third, the governmental effort to make the new airport a regional hub must take caution in optimizing the hubbing level (% of transitting passengers and freight) between the benefits and the costs. Further Studies may include optimal level of hubbing for the new airport and, quantification of the impact of the new airport on the national economy depending on the degree of hubbing.

• Proceedings of the Korea Association of Information Systems Conference
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• 2003.05a
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• pp.183-197
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• 2003

This paper introduces the public-oriented e-Hub construction for strategic alliances in the community. The public-oriented e-Hub can link with all Participating internet firms on the ba business models, and consequently help them share their core competence, management resource Based upon this perspective, this paper presents the procedures corresponding with social network strategic alliances of small and medium internet firms. In addition, this paper tries to analyze th among degree of competition, potential of strategic alliance, and financial performance. The resu the firms with more easily accepting various strategic alliances make higher financial performance competitive environment. This suggests that strategic alliances through the public-oriented e-Hub virtual community provide the internet firms with various opportunities

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1285-1286
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• 2006

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.3
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• pp.201-213
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• 2009

An Airport is important space and even stands for the country because diverse people from other countries use a variety of facilities in the gateway to the country. Therefore, It is urgent for those people to increase efficiency and convenience of its usage. But we have a problem with process of passenger and this paper with the object of finding the solution in case study. This paper focus on information system, especially Intelligent Airport Information System to streamline process of passenger. There are a few of countries adopted this system in process. Therefore, IIAC(Incheon International Airport Corporation) establishing u-Information HUB System. It is unique and differential characteristics to Facilitation and increase passenger's satisfaction. u-Information HUB system unified stakeholder's process of Facilitation in Air Traffic Sides. u-Information HUB system gets the highest state of efficiency to Facilitation. This Paper is attempt to find new effort