• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.515-524
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• 2022

The turnout system of the sleeper floating tracks (STEDEF) on urban transit is a Anti-vibration track composed of a wooden sleeper embedded in a concrete bed and a sleeper resilience pad under the sleeper. Therefore, deterioration and changes in spring stiffness of the sleeper resilience pad could be cause changes in sleeper support conditions. The damage amount of manganese crossings that occurred during the current service period of about 21 years was investigated to be about 17% of the total amount of crossings, and it was analyzed that the damage amount increased after 15 years of use (accumulated passing tonnage of about 550 million tons). In this study, parameter analysis (wheel position, sleeper support condition, and dynamic wheel load) was performed using a three-dimensional numerical model that simulated real manganese crossing and wheel profile, to analyze the damage type and cause of manganese crossing that occurred in the actual field. As a result of this study, when the voided sleeper occurred in the sleeper around the nose, the stress generated in the crossing nose exceeded the yield strength according to the dynamic wheel load considering the design track impact factor. In addition, the analysis results were evaluated to be in good agreement with the location of damage that occurred in the actual field. Therefore, in order to minimize the damage of the manganese crossing, it is necessary to keep the sleeper support condition around the nose part constant. In addition, by considering the uniformity of the boundary conditions under the sleepers, it was analyzed that it would be advantageous to to replace the sleeper resilience pad together when replacing the damaged manganese crossing.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.1
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• pp.23-29
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• 2008

The railway system is worldwide recognized as a safe mean of transportation. However, railroad accidents and incidents continue to occur. Due to the nature of the railway system that consist of many mechanical parties, it is apparently difficult to eliminate probability of accidents and incidents completely. Therefore, through the analysis of railroad accidents and incidents, it is very important to trace the various factors affecting the accidents and incidents. In this study, we performed the analysis of rail-road accidents due to track defects in foreign countries; United States of America, England, Canada, Australia. As a result of its investigation of the accidents, major risk factors are proposed in this study.

• Journal of the Korean Geotechnical Society
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• v.29 no.10
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• pp.57-66
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• 2013

Societal interest on a faster transportation demands an increase of the train speed exceeding current operation speed of 350 km/h. To trace the pattern of variations in displacements and subsoil stresses in the concrete slab track system, finite element simulations were conducted. For a simple track-vehicle modeling, a mass-point system representing the moving train load was developed. Dynamic responses with various train speeds from 100 to 700 km/h were investigated. As train speeds increase the displacement at rail and subsoil increases nonlinearly, whereas significant dynamic amplification at the critical velocity has not been found. At low train speed, the velocity of elastic wave carrying elastic energy is faster than the train speed. At high train speed exceeding 400 km/h, however, the train speed is approximately identical to the elastic wave velocity. Nonlinearity in the stress history in subsoil is amplified with increasing train speeds, which may cause significant plastic strains in path-dependent subsoil materials.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.2
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• pp.33-40
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• 2018

There are lots of literature about connected car system from industry and academia. The connected car is a smart car integrated with IT technology that is connected to people, vehicles and traffic management systems. It is important to V2I (vehicle to infrastructure) communication which is the connection between the vehicle and the infrastructure. CIM (cooperative intersection management) is a device to manage the communication between vehicle and infrastructure. In this paper, we analyze two intelligent vehicle control methods using CIM at non-signalized intersections. In the first method, a vehicle to pass through intersection needs to reserve a resource of intersection. In the second method, trajectory patterns on pre-planned vehicles are classified to pass through intersection. We analyze case studies of two methods to be implemented by DP(dynamic programming) and ACO(ant colony optimization) algorithms. The methods can be reasonably improved by placing importance on vehicles or controlling speeds of vehicles.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.614-627
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• 2018

Urban railway lines have been constructed adjacent to residential buildings and urban areas. The expansion of transportation networks and reconstruction of residential buildings in highly populated urban areas require deep excavations in areas adjacent to urban railways. Mobilized soil stresses and changes in the groundwater level induced by deep excavations results in track irregularities in urban railways. In this study, a three-dimensional finite difference model using the commercial program FLAC3D was adopted to estimate the horizontal displacements of earth retaining structures, settlements of backfill, the stability of track irregularity and underground box structure based on the criteria of each railway organization and its relationships. In deep excavations, a change in groundwater level induces relatively very small differences for track gauge irregularities, whereas relatively large differences for longitudinal irregularities of 72.5%, twist irregularities of 83.3%, cross level irregularities of 61.9%, and alignments of 43.3% were found to be the maximum differences when the horizontal displacement of earth retaining wall and settlement of backfill were 65.1% and 21.4%, respectively, because the groundwater level (GWL) on the ground surface-mobilized tensile strength of the underground box structure exceeds the allowable value. Therefore, three-dimensional numerical analysis was performed in this study. Overall, real-time monitoring should be carried out to prevent railway accidents in advance when a deep excavation adjacent to urban railway structures is constructed.

• Journal of the Korean Society for Railway
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• v.14 no.2
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• pp.188-193
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• 2011

In order to solve urban transportation problems, the various alternatives are presented to the public transportation system but the master plan of construction and operation is that there is no validity. PRT unlike other public transport system, is a new transport system that can respond appropriately, to solve the traffic demand, environmental and energy problems. Meanwhile, national and international PRT system was not commercially and the actual construction and operation of the PRT in case of base research is not well established. In this paper, PRT concept was established as the new transportation system, the target area(Nan-gok area) was selected to examine the feasibility of PRT systems and the corridor analysis method has been developed to predict the PRT demand as a basic material of planning process.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.2
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• pp.131-140
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• 2022

Installing Continuous Welded Rail (CWR) is one of the economical ways to resolve the challenges of noise, vibration, and the open-deck steel railway bridge impact, and the SSF method using the interlocking sleeper fastener has recently been developed. In this study, the method employed for determining the optimum vertical stiffness of the sleeper pad installed under the bridge sleeper, which is utilized to adjust the rail height and absorb shock when the train passes when the interlocking sleeper fastener is applied, is presented. To determine the optimal vertical stiffness of the sleeper pad, related existing design codes are reviewed, and, running safety, ride comfort, track safety, and bridge vibration according to the change in the vertical stiffness of the sleeper pad are estimated via flexible multi-body dynamic analysis,. The flexible multi-body dynamic analysis is performed using commercial programs ABAQUS and VI-Rail. The numerical analysis is conducted using the bridge model for a 30m-long plate girder bridge, and the response is calculated when passing ITX Saemaeul and KTX vehicles and freight wagon when the vertical stiffness of the sleeper pad is altered from 7.5 kN/mm to 240 kN/mm. The optimum stiffness of the sleeper pad is calculated as 200 kN/mm under the conditions of the track components applied to the numerical analysis.

• 전기의세계
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• v.39 no.5
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• pp.68-75
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• 1990

급속한 경제발전과 이에 대응한 교통인구의 증가로 운송시스템의 속도 경쟁은 날로 심화되고 있다. 그러나, 기존의 차륜구동 시스템은 본질적으로 궤도와 차륜의 마찰에 의하여 추진력을 얻기 때문에 평균 최대속도 250Km/h(상한 최대속도 350Km/h)수준이며 소음, 진동 등의 많은 문제점이 있다. 이러한 단점을 극복하기 위하여 선진 외국에서는 부상식 열차의 개발에 관심을 표명하여 1960년대 후반부터 열차와 공기부상식 열차에 대한 연구를 병행하였다. 1970년대 중반까지 프랑스, 영국, 미국 등에서 개발이 진행된 공기 부상식 열차는 고속 주행 및 환경 문제 등에 문제점이 많아 실용화에는 이루지 못하고 신교통 시스템에 부분적으로 적용되고 있는 실정이다. 그러나 자기부상 열차는 Power Electronics 및 자기관련 기술의 급속한 발전에 힘입어 현재 실용화 단계에 이르고 있다. 특히 자기부상(Magnetic Levitation : Maglev) 시스템은 레일과의 마찰력에 의해 추진하는 방식이 아니기 때문에 본질적으로 고속성, 무공해, 안정성, 신뢰성, 경제성 그리고 승차감이 뛰어나다. Maglev는 레일 표면에서 자력을 이용해서 약 1.0cm 또는 10cm 가량 부상한 상태에서 주행하기 때문에 외부와의 물리적인 접촉이 필요 없어 마찰에 의한 소음, 공해, 마모 등이 없는 대단히 이상적인 미래의 운송 수단으로 각광을 받고 있다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1040-1041
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• 2015

전용의 궤도에서 무인자동으로 승객의 요구에 따라 출발지에서 목적지까지 최적의 경로로 논스톱으로 운행하며, 높은 시스템 접근성과 프라이버시 보장 등 승용차 수준의 서비스 제공이 가능한 대중교통수단인 PRT의 운행관리를 위해 3D 그래픽 기반의 중앙제어 시스템을 개발하였다. PRT는 정거장을 필요에 따라 본선 또는 측선으로 설치가 가능하며, 승객의 요청에 따라 배차서비스를 수요에 탄력적으로 대응할 수 있다. 본 연구에서는 PRT 차량의 운행상황을 직관적으로 모니터링하기 위해 3D 그래픽 기반 운영제어 시스템을 개발하였으며, 승객이 요청한 차량이 정확하게 배차되어 탑승하였는지 확인하기 위한 운행 보조 시스템을 설계하였다.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.166-168
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• 2006

새로운 도시교통 시스템을 개발하기 위하여 시스템의 적용지역 검토 후 운영자, 이용자, 공급자 측면에서의 요구사항 도출과 아울러 이를 토대로 하여 시스템 요구사항을 도출하였다. 이는 기능 및 성능으로 구분할 수 있고 하부시스템별로 기능과 성능을 할당하여 각 하부시스템의 기능과 주요 장치가 갖추어야 할 조건, 용량 등을 정의하였다. 또한 환경요구사항 및 하부 시스템별 기기의 동작 조건등을 정의하여 시스템 개념을 확립하였다.