• Proceedings of the Korea Information Processing Society Conference
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• 2002.11c
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• pp.2141-2144
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• 2002

최근 인터넷 기술의 급속한 보급과 발전은 컴퓨팅 패러다임의 변화를 촉진시키고 있다. 이러한 컴퓨팅 패러다임 변화의 중심에는 인터넷을 기반으로 네트워크화 되는 e비즈니스가 등장하였다. e비즈니스 환경에서 기업들은 다양한 거래 파트너를 관리하게 된다. 이로 인해 보다 효율적인 관리가 필요하며 자주 발생하는 거래 파트너의 변화에 신속히 대처하기 위해 이를 관장하고 처리해주는 시스템이 필요하다. 또한 거래 파트너와의 메시지 교환에 있어서 메시지 전송에 대한 요청/응답을 담하고 응답 지연과 실패에 대한 처리가 필요하다. 따라서 본 논문에서는 SOAP(Simple Object Access Protocol)을 이용한 XML Hub 시스템을 설계하여 이를 해결하고자 한다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.402-408
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• 2003

Now many major airports in the world which operate strategic alliance or Hub & Spoke system have met capacity restriction and confusion problems. And the time and the walking distance for boarding to flight are important standard to measure customer convenience. And the effective gate assignment guarantees customers convenience as well as increasing airport capacity without expanding established airport equipments. So it can be a major concern to manage airports. So this paper formulate gate assignment problem in the hub airport not quadratic assignment problem but a improved single-period integer problem which is minimize local and transit passengers I walking distance. As a result, this study will present a method producing optimal gate assignment result using optimization software. We use real flights and gates data in the national airport, so we will compare a assignment results with a real airport assignment results and previous researches and analyze those results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.9 s.114
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• pp.912-918
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• 2006

A modeling method for the vibration analysis of rotating multi-blade systems considering the coupling stiffness effect is presented in this paper. Blades are assumed as cantilever beams and the coupling stiffness effect originates from disc or shroud between blades. As the angular speed, hub radius ratio, and the coupling stiffness vary, the natural frequencies of the system vary. Numerical results show that the coupling stiffness is very important to estimate the natural frequencies. Along with the natural frequencies, associated mode shapes, critical angular speed, and critical hub radius ratio are obtained through the analysis.

• Journal of Navigation and Port Research
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• v.26 no.4
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• pp.455-463
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• 2002

In 1990s the debate on very large ships made the Mega ship and mega port concept emerge. Many studies have bees done on such big ships by consultant, naval architects, port designers, ship operators, economists etc,. with different points of view and results. This paper, by reviewing the literature systematically, identifies limitations and major issues, and suggests directions for further studies.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1354-1359
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• 2006

A modeling method for the vibration analysis of rotating multi-blade systems considering the coupling stiffness effect is presented in this paper. Blades are assumed as cantilever beams and the coupling stiffness effect originates from disc or shroud between blades. As the angular speed, hub radius ratio, and the coupling stiffness vary, the natural frequencies of the system vary. Numerical results show that the coupling stiffness is very important to estimate the natural frequencies. Along with the natural frequencies, associated mode shapes, critical angular speed, and critical hub radius ratio are obtained through the analysis.

• Journal of Korea Port Economic Association
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• v.21 no.3
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• pp.61-81
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• 2005

China has increased 10 percent every year since 1978. In particular, development and growth of Chinese ports make a remarkable in that the marine and coastal transportation handles the 90 percent of export-import cargo. This growth is beginning to threaten Korea's ports which are striving to become the hub of Northeast Asia logistics. Furthermore, the hub strategy of Northeast Asia is closely related to transshipment cargo invitation. The results of documents research indicate Busan and Gwangyang ports play an important role as an intermediate stopover between China and America. The ways to achieve transshipment cargo invitation are the construction of transshipment system based on the supply chain between korea and china, the maximization of trading volumes creation, equipment of ports infrastructure, and the constructions of the rail, road, coastal transportation infrastructures.

• Journal of Korea Port Economic Association
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• v.21 no.3
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• pp.35-59
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• 2005

The Purpose of this study is to exmaine fundamental problems of Gwangyang Port and draw up plans of its Hub Port. Gwangyang Port has been gradually reduced container cargo increase rate. on account of large development of Chinese Port, undevelopment of Hinterland, Port facilities of Gwangyang Port. We should develop hinterland to be closely connected with Port Cluster, Business City, Free Economic Zone to increase cargo volume. and in order to increase transshipment cargo volume, We should prepare diverse plans that can induce Chinese and Japanese transshipment cargo. Gwangyang Port and Busan Port should be managed united one port system by a Port Authority to strengthen international competitiveness. Activation of new ports for the most part call for full support by Government at the beginning. Gwangyang Port's future it can be if Government has strong will.

• International Journal of Air-Conditioning and Refrigeration
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• v.11 no.4
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• pp.178-187
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• 2003

In this study, ventilation flow rate and pressure rise through a tunnel are simulated numerically using computational fluid dynamics (CFD) for various conditions such as roughness height of the surface of tunnel, swirl angle and hub/tip ratio of jet fan, and entrance and exit effects. By using a modified wall function, friction factor can be predicted with respect to the Moody chart within 10% of error for the circular pipe flow and 15% for the present tunnel. For more accurate design, the effect of the swirl angle and hub/tip ratio of jet fan, which is not included in the theoretical equation of pressure rise by jet fan needs to be considered.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.347-350
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• 1998

본 논문에서는 최근 광대역 무선 가입자망으로 각광받고 있는 LMDS(Local Multipoint distribution Service)시스템에서 Head-End 의 AIU(Air Interface Unit)와 HUB 사이의 거리에 따른 전송지연 시간과 HUB 와 가입자 장치(CPE:Customer Premises Equipment)내의 NIU(Network Interface Unit)간의 전송 지연 시간에 의하여 서비스 반경이 제한되어 지는 것에 관하여 살펴보고 적절한 서비스 반경에 대하여 제안하였다.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.280-281
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• 2017

본 논문에서는 기존의 배풍기 효율을 높이고 크기를 줄이기 위해 임펠러의 속도를 높이는 설계에 관한 연구다. 임펠러 속도는 5500rpm으로 증가시키고 크기는 320mm에서 250mm로 줄였으며 효율과 최대 풍량을 향상키기기 위해 임펠러의 Hub/Tip 비율을 줄이며, 날개각도에 변화를 주는 방식을 제안한다. Hub/Tip 비율이 줄어들면 유량이 통과하는 면적이 넓어지게 되는 효과를 얻게 되고, 임펠러 중심거리에 따른 날개 각도를 변화시키면 풍압과 풍량이 달라지는 효과를 얻게 되어 동일한 rpm으로 회전하는 배풍기의 효율을 높일 수 있다. 설계된 구동용 SRM과 임펠러의 설계에 따른 운전 특성을 시뮬레이션을 통해 해석하고자 한다.