• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2348-2356
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• 2011

In recent years, many researches for DC power distributed system (PDS) are being preformed and the importance of the DC PDS is more and more emphasized. Furthermore, in the railway system, the DC PDS is used in subway station lighting, facilities, etc. In the DC PDS, DC bus voltage instability may be occurred by the operation of multiple parallel loads such as pulsed power load, motor drive system, and constant power loads. Thus, good quality and high reliability for electric power are required and voltage bus conditioner (VBC) may be used the DC PDS. The VBC is a DC/DC converter for mitigation of the bus transients. In this paper, adaptive controller is designed. The simulation results by PSIM are presented for validating the proposed control algorithm.

• 한국멀티미디어학회논문지
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• 제18권3호
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• pp.287-297
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• 2015

A railway security detection system is very important. There are many safety factors that directly affect the safe operation of trains. Security detection technology can be divided into passive and active approaches. In this paper, we will first survey the railway security systems and compare them. We will also propose a subway security detection system with computer vision technology, which can detect three kinds of problems: the spark problem, the obstacle problem, and the lost screw problem. The spark and obstacle detection methods are unique in our system. In our experiment using about 900 input test images, we obtained about a 99.8% performance in F- measure for the spark detection problem, and about 94.7% for the obstacle detection problem.

• 한국철도학회논문집
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• 제16권6호
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• pp.540-550
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• 2013

본 논문에서는 철도통신시스템을 위해 필요한 주파수 소요량을 계산하기 위한 방법을 제안한다. 철도통신시스템을 위한 주파수소요량 계산에 최적화된 방법을 유도하기 위하여, 먼저 기존의 일반 이동통신시스템의 주파수 소요량 측정에 사용되었던 방법인 ITU-R M.1390을 분석한 후, 차세대 철도통신시스템에서 요구하는 서비스들을 세분화하여 정의하고, 철도통신을 위해 수정된 주파수 소요량 프로세스를 제안한다. 그리고 실제 현장조사를 통해 습득된 장비정보들을 제안한 계산방법에 적용하여 현재, 5년 후, 10년 후 시점의 예상 주파수 소요량을 계산한다.

• International Journal of Internet, Broadcasting and Communication
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• 제13권4호
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• pp.112-120
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• 2021

Recently, the number of consumers using digital online distribution platforms is increasing. This caused the rapid growth of the e-commerce market and increased delivery volume in urban areas. The logistics system, designed ar006Fund the city center to handle the delivery volume, operates a delivery system from the outskirts of the city to the urban area using cargo trucks. This maintains an ecosystem of high-cost and inefficient structures that increase social costs such as road traffic congestion and environmental problems. To solve this problem, research is being conducted worldwide to establish a high-efficiency urban joint logistics system using urban railway facilities and underground space infrastructure existing in existing cities. The joint logistics system begins with linking unmanned delivery automation services that link terminal delivery such as cargo classification and stacking, infrastructure construction that performs cargo transfer function by separating from passengers such as using cargo platform. To this end, it is necessary to apply the device to the vertical and horizontal transportation machine supporting the vertical transfer in the flat space of the joint logistics terminal, which is the base technology for transporting cargo using the transfer robot to the destination designated as a freight-only urban railway vehicle. Therefore, this paper aims to derive holistic viewpoints needs for design requirements for vertical and vertical transportation machines and freight transportation standard containers, which are underground railway logistics transport devices to be constructed by urban logistics ecosystem changes.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.3278-3288
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• 2011

Bulk freight is transported by a freight car, ship and tank lorry without packaging in a state of particles or powders. In korea, the main bulk freight include oil, grain, coal, cement, iron ore and these are occupied nearly 30% of the volume of gross domestic freight transportation. Therefore it is in important to transport efficient bulk freight transport system for the improvement of national distribution competitive as raw material for industry. Generally environment-friendly transfer modes such as railway and sea transport play an important role in bulk freight transport due to the mass transfer characteristics of bulk freight. This study is carried out for examining the problem of oil, grain, coal, cement, ore transportation through analyzing distribution flow of items and understanding characters of transfer modes.

• 조명전기설비학회논문지
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• 제15권3호
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• pp.91-96
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• 2001

본 논문은 전기철도시스템 고압 배전선로에서 직격뇌에 의한 가공지선의 영향에 대해서 설명하였다. EMTP를 사용하여 가공지선과 보안기의 영향을 정량적으로 분석하였다. 또한 전차선로의 구조변경과 피격전류의 크기, 파미값의 변화에 대한 영향도 평가하였다. 분석결과 기존 시스템에 가공지선의 설치는 전기철도시스템 고압 배전선로에 유도되는 피격전압을 억제하는 효과가 있음을 입증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 전력전자학술대회
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• pp.342-343
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• 2019

This paper explores the power distribution problem of parallel-connected inverter system which supplies auxiliary power for railway facilities. We propose a droop control method which facilities power distribution and restrain of voltage drop by tracking the average power control command by adjusting the virtual impedance. The performance of proposed droop method is verified by the PSIM simulation.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.627-632
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• 2010

Recently the research for lightening the railway vehicle is actively made according to the demand of the environment-friendly technology development contributing to the energy cost reduction and the green growth. The railway vehicle lightweight research is expanded to the load-supporting first structure from the secondary structure which doesn't support the load. After the composite car body development used in the Korean tilting train is completed, the composite bogie frame development in which the weight reduction efficiency is large is progressed. In this paper, distributed strain was monitored when the train load was added to the central part of the composite bogie side-frame. By using the optical fiber which was attached to the lower part of the side-frame and the developed Brillouin correlation domain analysis (BOCDA) system, the strain distribution could be measured with 3cm step over 3m section. This strain distribution was compared with the design value by the FE analysis when the load of 14ton and 18ton added. This experiment can verify the manufactured composite bogie side-frame.

• 대한지리학회지
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• 제38권4호
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• pp.591-609
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• 2003

본 연구는 중국 철도망의 구조와 철도여객 및 화물 유동에 대한 분석을 통하여 중국 도시 네트워크의 특징과 변화를 밝히는 것을 주요 목적으로 하였다. 중국 도시의 접근성은 허난성을 중심으로 한 중부지역이 가장 높고 주변으로 향할수록 접근성이 떨어진다. 도시 네트워크의 중심은 중부지역에서 동부지역으로 이동하였으며, 3개의 남북방향 축과 주요 도시들의 지역 중심성은 여전하지만 그들의 영향권은 확대되고 중심성도 분산되었다. 도시 네트워크의 계층구조는 3단계로 구분할 수 있는데 1단계 계층에서 대부분의 영향권은 도시 성(자치구) 범위를 크게 벗어나지 않았고, 2단계 계층에서는 대부분의 지역에서 영향권 교차현상이 나타났으며 선형 패턴이 더욱 뚜렷하였다. 3단계에서는 5대 영향권으로 구분되었다.

• 전기학회논문지
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• 제62권8호
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• pp.1177-1183
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• 2013

In this paper, the analysis of inspection period bases on reliability is suggested in the field of traction power system. Even though there are several maintenance models, the most commonly used maintenance assessment has been focused on time based maintenance in real traction power systems. The maintenance intervals are selected on the basis of long-time experience. It ensures high availability and exact planning of staff. Reliability centered maintenance, which evaluates criticality and severity of each failure mode, achieves the operation, maintenance, and cost-effective improvement that will manage the risks of equipment. This paper deals with electrification in railway inspection frequency and applied reliability based inspection frequency instead of constant intervals. The distribution function of failure rate in traction power system belongs to Weibull function. Also, the fault data and the number of installed equipments for electrifications are collected. The failure history is investigated and classified in detail. Though these complicated procedures, it contribute to extend equipment lifetime and to reduce maintenance costs.