• Journal of the Korean Geographical Society
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• v.50 no.5
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• pp.527-541
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• 2015

The purpose of this study is to investigate the changes in the inter-city passenger flows since adapting the express rail system in Korea(KTX). For the purpose, we analyze the express bus and rail passenger annual flow data of the before and after adapting KTX. In first, we examine the changes in the time-distance parameters in the inter-city passenger flows of the express bus, general rail, and KTX by applying gravity model. The results reveal that express bus passenger flows are less sensible to the time-distance compare to the rail passenger flows, and the trends have been intensified over time. However, the time-distance parameters for the KTX passenger flows reveal the reverse relationships with the gravity model. The KTX passenger flows expand between the long distance cities. We also apply the MST(Maximum Spanning Tree) method to find out the spatial structural changes in the inter-city passenger flows. The number of hierarchies has been increased in the express bus and general rail passenger flows, while single hierarchical structure has been lasted in the KTX passenger flows.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.8
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• pp.728-733
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• 2008

Unsteady aerodynamic analysis of an air-pressure-levitated high-speed ground vehicle moving over the nonplanar ground surface are performed using the boundary-element method. The potential flow solution is included in a time-stepping loop and the wake is captured as part of the solution. When the vehicle moving inside the channel, the lift coefficient and the pitching moment coefficient of the vehicle are increased further because the air trapped by the channel increases the ground effect. In other words, the nonplanar ground surface such as the channel decreases further the longitudinal stability of the vehicle. On the other hand, there is little difference between the ground and the channel in the lateral stability of the vehicle because the lift increment due to the nonplanar ground surface such as the channel takes place on both sides of the wing with the same rate of increase.

• Bulletin of the Society of Naval Architects of Korea
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• v.32 no.1
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• pp.17-20
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• 1995

고전적인 고속선형에서 탈피한 새로운 형태의 고속선형에 대한 효시는 1960년경의 수중관통형 수중익선의 개발이라 할 수 있다. 그 후, 1980년대까지는 일반적인 중,저 속의 화물선 및 LNG 운반선에 대한 유체역학적 특성의 향상을 위한 선형 개발 경쟁이 국내외적으로 활발하게 진행 되어져 왔다. 그러므로, 이러한 기간중인 약 20여년간은, 선박의 선형 개발면에서는 기존의 선 박형태를 탈피하지 못한 채 유체역학적 성능을 향상시키려는 소극적인 진전이 있었을 뿐, 발전이 매우 더딘 편이었다. 1980년대 후반에 들어서 국내외적인 물동량의 증가와 해상고속운송의 필 요성이 대두되면서 고속선의 개발에 대한 열기가 시작되었다. 그간의 고속선개발은 주로 미국을 중심으로 군사적인 목적면에서 진행되어 왔고, 일본은 거의 일반상선의 선형개발에 중점을 두어 왔으나, 1980년대 후반부터는 일본도 아시아지역에서의 물동량변화와 고속화의 필요성에 따라 고속선 개발에 뛰어들게 되었다[1, 2, 3]. 특히 최근의 50knots를 넘는 대형의 화물운송용 초고 속선 개발은 주목할 만한 연구가 되고 있다'4'. 국내에서도 1990년대에 들어서면서 소형이지만 이러한 초고속선의 선형개발을 시작하게 되었으며, 실용화된 예도 몇몇을 가지고 있다. 본고에 서는 이제까지 연구된 몇가지 초고속선형들에 대한 예와 장단점, 또한 조파저항 성능면에 대해 기술하여 보고자 한다.

• 전기의세계
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• v.44 no.9
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• pp.38-42
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• 1995

최근 산업 발달과 더불어 증가하는 운송 물량과 일일 생활권의 확대 및 생활 수준의 향상으로 인해, 빠르고 편리하며 안전한 양질의 운송수단에 대한 요구가 점차 높아지고 있다. 이러한 요구의 증대는 자동차와 같은 개별적 운송수단의 증대를 유발하였으며, 기존의 제한된 도로에 대한 운송수단의 점유율을 증가시켰다. 그 결과, 운송소요시간이 불규칙해져 평균수송량이 감소했으며 이로 인해 운송효율이 급격히 저하되었다. 따라서 많은 양의 물량을 한 번에 수송할 수 있으며, 정확한 운송시간을 보장하는 철도차량과 같은 운송수단의 확대가 절실하게 되었다. 도심 내에서는 전기 철도차량인 지하철을 설치하여 점증하는 수요를 충족시켜 왔으며, 도심간에는 기존의 궤도를 이용하는 차량의 운송횟수를 늘려 운송량을 증가시켜 왔다. 그러나 최근, 계속된 수요의 증가로 인해 기존 방식의 철도차량 운송 능력도 포화상태에 이르게 되었다. 이에 따라 기존의 제한된 선로에서 운송량을 향상시키기 위한 연구와 함께 새로운 철도노선 확장 및 차량의 고속화를 위한 연구가 활발히 진행되고 있다.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.107-118
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• 2011

This paper performs flow analysis of ultra-high speed vehicle inside the long distance tunnel. One and three dimensional hybrid mesh was used for describing moving motion and flow analysis of an vehicle inside a long distance tunnel which over 20 km. Flow analysis and aerodynamic drag measuring were performed by three dimensional mesh: around vehicle, and pressure waves of a tunnel was measured by one dimensional mesh: the other region where rare changing of flow pattern.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.2075-2089
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• 2008

Improvement of transport system is necessary to advance the freight traffic meanwhile logistics are getting bigger and faster by worldwide tendency. The link between each transportations occurs bottleneck state and it raises the necessity of non-stop mixed transport system which can reduce the cost of logistics. DMT(Dual Mode Trailer) was designed to use road and railway at the same time for door to door service. It is called DMT for every transport system which can connect between road and railway in Korea. This study would like to examine the present condition of promotion for localization of DMT which is new idea and technology and suggest the new subjects from now.

• Journal of KSNVE
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• v.14 no.2
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• pp.35-45
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• 2004

한국에서의 철도는 1890년대 말 서울-노량진간(33 km)을 시속 20km/h로 1시간 30분에 주파한 이래 100여년이 지난 2004년 4월 1일 시속 300 km/h 의 고속철도시대를 개막하였다. 고속철도의 개통은 전국을 한나절 생활권으로 묶으면서 국민 생활 전반에 큰 변화를 가져올 것으로 기대된다. 지역균형 발전과 지역경제 활성화에 기여할 뿐만 아니라 사람과 물류의 이동시간을 단축시켜 운송 및 물류비용을 절감시키는 등 고속철도는 국토의 대동맥 역할을 담당할 신교통수단으로서 그 자리를 굳건히 할 것이다.(중략)

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.119-127
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• 2011

This paper shows development of 1-3 dimensional hybrid mesh method to analysis flow induced by ultra-high speed vehicle inside a long distance tunnel. For three-dimensional analysis of the tunnel system many meshes are required. However it is not efficient to calculate the whole tunnel system in three-dimension. Therefore in this paper, three-dimension meshes was used to describe stations, shafts and around vehicle, and one-dimension meshes was used to describe the tunnel except these three sections. And unsteady flow analysis of the ultra-high speed vehicle was performed with UDFs in commercial software, Ansys vr. 12.0.

• Fire Protection Technology
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• s.35
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• pp.16-23
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• 2003

• Tunnel and Underground Space
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• v.28 no.3
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• pp.247-257
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• 2018

High-speed trains have been developed widely in many countries in order to transport large quantity of people and commodities rapidly. When a high speed train enters a tunnel, aerodynamic resistance is generated suddenly. The resistance caused from air pressure induces micro pressure wave and discomfort to passengers in a train. Therefore, a pressure relief system should be installed in a tunnel to reduce the resistance acting against the running train in a tunnel. Additionally, the shape of a grain should be streamlined in order to reduce aerodynamic resistance caused by a high-speed train. The cross-section of a tunnel also should be carefully designed to reduce discomfort of passengers. This study represents the effect of pressure relief ducts installed between two running tunnels. The pressure relief duct was integrated with a cross-passage in order to save cost and construction time. One-dimensional network numerical simulations were carried out in order to estimate the effect of pressure relief systems.