• Structural Engineering and Mechanics
• /
• 제17권1호
• /
• pp.113-140
• /
• 2004

A mixed eight-node hexahedral element formulated via the Hu-Washizu principle as well as the field extrapolation technique is presented. The mixed element with only three translational degrees of freedom at each node can provide extremely accurate and reliable performance for popular benchmark problems such as spacial beams, plates, shells as well as general three-dimensional elasticity problems. Numerical calculations also show that when extremely skewed and coarse meshes and nearly incompressible materials are used, the proposed mixed element can still possess excellent behaviour. The mixed formulation starts with introduction of a parallelepiped domain associated with the given general eight-node hexahedral element. Then, the assumed strain field at the nodal level is constructed via the Hu-Washizu variational principle for that associated parallelepiped domain. Finally, the assumed strain field at the nodal level of the given hexahedral element is established by using the field extrapolation technique, and then by using the trilinear shape functions the assumed strain field of the whole element domain is obtained. All matrices involved in establishing the element stiffness matrix can be evaluated analytically and expressed explicitly; however, a 24 by 24 matrix has to be inverted to construct the displacement extrapolation matrix. The proposed hexahedral element satisfies the patch test as long as the element with a shape of parallelepiped.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2006년도 추계학술대회 논문집
• /
• pp.552-557
• /
• 2006

Since the 20th century, the business of railway was invaded by the invention of airplanes and vehicles in the field of the transportation of passenger and commercial products, however, in the 21st century, the fervent development of a high-speed railway made possible the huge capacity of transporting passengers and commercial freight, so the railway industry is facing a new era of railway revolution. The 200 years old railway tradition includes the history of railway bridges built in areas of river, valley and metropolitan region and in that, the number of constructions of railway bridges that is composed of cable-stayed bridges is increasing as one of the most optimal bridges considering the quality of materials and the span of continuous-welded long rail. Thanks to the minimized effects of the fixed load on the stiffening girder section by delivering the fixed load which is applied to the pylon with the composition of elastic supporting-points by using cables and the effective structural system that can throughly resist extra loads in addition to fixed load, the long-extended span of a bridge becomes possible. In this structural system, the load that is applied to the stiffening girder section forms a flow pattern and in the process of these load delivery, there will be a necessity to examine the concentration of stress occurred in the cable-anchor system of the cable.

• 한국재난정보학회 논문집
• /
• 제9권1호
• /
• pp.113-122
• /
• 2013

우리나라는 철도이용객 증가에 따라 여러 다양한 철도안전 관련 제도 등을 마련하고 있으며, 이러한 차원에서 철도 보안검색시스템의 도입을 검토 중에 있다. 본 연구는 철도 보안검색시스템 도입에 앞서 이에 대한 충분한 대비를 위하여 외국의 철도보안검색제도 시행현황을 살펴보고, 국내 도입가능한 철도보안 검색방법 등을 제시하였다. 또한, 철도이용자들을 대상으로 하여 철도 보안검색 제도 시행과 관련한 설문조사결과를 바탕으로 철도 보안검색 제도에 대한 견해, 제도 시행 시 문제점, 개선방안 등을 파악하였다. 결론적으로 고속철도역에 대한 시범적 실시를 통해 점진적 시스템 도입이 필요하다고 제안하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 제38회 하계학술대회
• /
• pp.1609-1611
• /
• 2007

The owner of underground metallic structures (gas pipeline, oil pipeline, water pipeline, etc) has a burden of responsibility for the corrosion protection in order to prevent big accidents like gas explosion, soil pollution, leakage and so on. So far, Cathodic Protection(CP) technology have been implemented for protection of underground systems. The stray current from DC subway system in Korea has affected the cathodic protection (CP) system of the buried pipelines adjacent to the railroads. In this aspect, KERI has developed a various mitigation method, drainage system through steel bar under the rail, a stray current gathering mesh system, insulation method between yard and main line, distributed ICCP(Impressed Current Cathodic System), High speed response rectifier, restrictive drainage system, Boding ICCP system. In this paper, the mechanism of mitigation method of DC stray current for underground metallic structures is described.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 제38회 하계학술대회
• /
• pp.1612-1614
• /
• 2007

The owner of underground metallic structures (gas pipeline, oil pipeline, water pipeline, etc) has a burden of responsibility for the corrosion protection in order to prevent big accidents like gas explosion, soil pollution, leakage and so on. So far, Cathodic Protection(CP) technology have been implemented for protection of underground systems. The stray current from DC subway system in Korea has affected the cathodic protection (CP) design of the buried pipelines adjacent to the railroads. In this aspect, KERI has developed a various mitigation method, drainage system through steel bar under the rail, a stray current gathering mesh system, insulation method between yard and main line, distributed ICCP(Impressed Current Cathodic System), High speed response rectifier, restrictive drainage system. We installed the mitigation system at the real field and test of its efficiency in Busan and Seoul, Korea. In this paper, the results of field test, especially, distributed ICCP system is described.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 추계학술대회 논문집
• /
• pp.1270-1278
• /
• 2008

A great deal of development has been made in the field of railroad control in Korea. Like the recent High speed railroad (KTX) and the intercity light rail train (LRT) are being vigorously promoted. Therefore, in concert with the new railroad development projects, improved train control technics are being applied. Along with the focus on these newly developed advanced technologies the need for a reliable safety system for the safety of the passengers and railroad control personnel alike is being intensified. New safety facilities are continuously being developed in order to safely introduce and develop these new technologies. There is an urgent need for research and development of safety facilities for the implementation of the presently developed facilities as well as for the presently being used. Therefore, this research will study the safe operation of Korean railroad and the implementation situation of the class, functionality, ensured safety range etc. of the safety facilities for users and operators. In studying the material of the kinds of implemented safety facilities and technologies being used abroad we have researched into the most suitable direction of development of safety facilities for the Korean railroad environment.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 추계학술대회 논문집
• /
• pp.657-665
• /
• 2008

The main transportation mode of long distance inter-city passenger trips is high-speed rail and the modal share of transportation has been changed profoundly since the KTX service has been started in the Kyung-Bu railroad transportation corridor in the day of 1 April, 2004. After an opening of KTX service in the second stage Kyung-Bu and Ho-Nam railroad transportation corridors, a capacity of incumbent railroads will be increased and operational environments of freight train will be improved. The purpose of this paper is to examine the impact of KTX service operation on the national logistics thoroughly. This paper establishes a deceptive scheme in the national railroad logistic transportation and a route operational strategy between the main origins and destinations efficiently considering the changes of the current freight transportation system in the future. We expect to achieve efficiency of logistic transportation in this paper through alternative routes for example Ho-Nam, Chang-Hang, Seo-Hae line.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 추계학술대회 논문집
• /
• pp.666-672
• /
• 2008

Train wheels are the most important part of the high-speed rail system with supporting body, running stably and safely. Wheel exchange and fix plan is computed by the worker who managing entire Train Maintenance Process based on his know-how so that this system is losing its reliability and accuracy. And predicting of the wheel's lifetime is absolutely difficult matter because of uncertainty between trains like mileage of the type of trains, condition of operation, curve section and wheel's cutting pattern. Therefore workers always used to hold many wheels. For this reason, the cost of stock is soar when the level of stock was normal. If the stock is sufficient, the cost of stock will rise. On the other hand, If the stock is deficient, we would have trouble that the plan of the train maintenance process will be failed. Thus this paper aimed at application that "Wheel Managing System" which is able to predict wheel's life-cycle and demands under the RIMS(Rolling-Stock Information Maintenance System) with analysing wheel exchanging and cutting status considering economical or stable aspects.

• 한국항공운항학회지
• /
• 제32권1호
• /
• pp.79-90
• /
• 2024

UAM is emerging due to the deepening population concentration in the metropolitan area and the problem of congested ground transportation in urban areas. Accordingly, along with research on eVTOL aircraft for UAM services, interest in vertiport, the interest in vertiports, the infrastructure that allows eVTOLs to take off and land, is also increasing. However, behind the concentration of population in the metropolitan area, aphenomenon of local extinction is occurring in conjunction with the aging population. AAM, which moves quickly through 3D space, can be an effective SOC facility in times of local extinction crisis. In this paper, we introduce a design plan from the perspective of a complex transper center for a regional hub-level vertiport that can connect with local high-speed rail and utilize local airports in compliance with the vertiport design guidelines issued by FAA(Federal Aviation Administration) and EASA(European union Aviation Safety Agency). We would like to present Vertiport's future operation plan.

• 한국지역지리학회지
• /
• 제10권2호
• /
• pp.252-266
• /
• 2004

본 연구는 신개념의 교통수단이 국토공간에 도입됨으로써 발생하는 공간조직 변화를 분석하기 위하여 프랑스 TGV교통망 건설이 가져온 프랑스 국토공간 조직의 변화를 국토 전체적인 공간조직 변화, 도시체계의 수정, 교통체계의 변화 양상 및 유럽 통합공간체계 측면에서 고찰하였다. 프랑스는 TCV 교통망 건설이후 20여년간 커다란 국토공간조직상의 변화를 겪게 되는데 지리적 단위마다 독특한 변화양상을 보이고 도시권의 관계적 위치에 따라서도 상이한 변화의 모습을 보이고 있다. 전체 국토 차원에서 TGV망 건설의 가장 큰 효과는 국토공간 수렴효과와 프랑스 국토가 Paris를 정점으로 한 고속교통망 체계로 연결된 것이다. 그러나 시간거리 축소효과는 각 지역의 고속철도망으로의 접근성과 연결성에 따라 차이를 나타내고 이는 지역간 개발기회의 불균등을 더욱 증폭시키는 부작용을 낳아 국토 공간의 불균형개발을 강화하는 요인이 되기도 한다. 지역적 차원에서는 TGV의 중간 경유역이 있는 지방 중소도시는 기존의 지역행정중심도시와 함께 지역경제 중심권으로 발전하여 단핵구조에서 다핵구조의 지역 공간구조로 이행하는 변화 양상이 나타난다. 도시권차원의 변화는 TGV역세권을 중심으로 신시가지 개발 및 경제집적지구의 성장으로 새로운 경제활동지구가 성장하였다. 현재 유럽국제 고속철도망의 연계건설 추진으로 각 유럽도시 권은 새롭게 편성되는 유럽 도시체계에서 경쟁력을 갖춘 고차 계층의 도시로 자리매김하기 위해 새로운 공간조직 전략을 통한 새로운 도시경쟁력창출을 모색하고 있다. 우리나라의 KTX교통망의 구축 또한 국토공간 조직의 변화를 동반할 것으로 예상된다. 따라서 향후 나타날 효과와 부작용을 미리 예견하여 세계화와 지방화시대에 적합한 경쟁력 있고 유연적인 교통체계로 발전시켜가야 한다.