• 한국철도학회논문집
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• 제7권4호
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• pp.400-405
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• 2004

Recently, MIMO communications are regarded as one of the most promising emerging wireless technologies. This paper investigates MIMO wireless systems and their applications in a railway communication system. We firstly discuss railway communication environments including propagation characteristics and radio channel modeling. Next, we consider channel estimate methods, which is a crucial issue under rapidly varying channel condition due to the movement of trains. Channel estimation methods for MIMO systems are addressed and the effect of estimation error is studied. We also have performed simulations for transmit beamforming system and STBC(Space-time block coding) to investigate the performance of MIMO schemes in railway systems.

• 한국정밀공학회지
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• 제31권9호
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• pp.777-782
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• 2014

Usually, railway axles are designed for infinite life based on endurance limit of the material and the axle is not fractured immediately when a surface crack initiated. The railway axles have been inspected regularly by NDT such as ultrasonic testing, magnetic testing and eddy current testing and so on. Because the axle failure is profoundly influenced by the probability of missing a fatigue crack during an NDT inspection, it is necessary to evaluate the Non Destructive Interval of railway axle. In the present paper, the Non Destructive Interval of railway axle based on fracture mechanics and finite element analysis was investigated. It was shown that the Non Destructive Interval of railway axle can be evaluated using fracture mechanics approach and extended using NDT which a crack can detect clearly.

• International Journal of Railway
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• 제5권1호
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• pp.38-47
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• 2012

At present among the most important problems in the field of traction systems of railway vehicles are the following: 1) the minimization of the mass-and-overall dimensions of the drive systems; 2) the increase of the drive systems reliability and obtaining their higher fault-tolerance abilities; 3) the minimization of the motion speed pulsations and its oscillations, etc. The results of the researches received by the authors of this paper show that the use of the multiphase (i.e. having the number of phases more than four) inverter-fed induction motors in these traction systems is the most effective way of solving the above mentioned problems. In this case the motion speed oscillations can be decreased only by the increase of the drive phase number without any change in the inverter control algorithm. In addition, the application of some non-traditional control methods in the multiphase asynchronous traction drive system of a railway vehicle allows to decrease the mass-and-overall dimensions of the system and to improve its reliability and some other technical-and economic characteristics.

• 한국철도학회논문집
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• 제14권2호
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• pp.87-93
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• 2011

본 연구는 Five-9's 가용도를 달성하기 위한 고가용도 시스템의 가용도 모델을 기술한다. 현대의 철도시스템은 지속적으로 서비스가 제공되어야 하는 고가용도 시스템으로 이러한 고가용도 서비스의 중요한 특성은 이동통신, 철도시스템, 정보운영 및 웹기반 사업 등 많은 현대의 사업에 필수적이며, 아키텍처 기반의 시스템 가용도 모델은 고가용도 목표의 만족여부를 평가하는 데 매우 유용하다. 마코브 모델 접근은 관련 시스템엔지니어가 시스템고장 및 고장복구 프로세스를 모델링할 때 직관적으로 적용가능하다. 본 연구는 UML2.0을 사용하여 개선된 가용도 모델을 제시하였다. 이러한 아키텍처기반의 시스템 가용도 모델은 철도시스템에 매우 의미있게 적용될 수 있다.

• 조명전기설비학회논문지
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• 제24권8호
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• pp.48-54
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• 2010

교류 전기철도 시스템은 비선형 단상 부하인 차량의 부하특성으로 인해 고조파 왜곡, 무효전력 발생, 3상 불평형과 같은 전기품질 문제를 가지고 있다. 이 같은 전기품질 문제는 철도 시스템뿐만 아니라 철도와 연계된 다른 건전한 계통에도 악영향을 미치게 된다. 따라서 본 논문에서는 이와 같은 전기철도 급전시스템의 전기품질 문제를 보상하기 위해 철도용 전기품질 보상장치(RPQC; railway power quality conditioner)를 적용하고, SRF(synchronous-reference-frame) 제어를 이용한 RPQC의 제어방법을 제안한다. 제안하는 제어방법을 통해 RPQC는 고조파 왜곡, 무효전력, 부하 불평형과 같은 전기품질 문제를 순시적으로 보상할 수 있으며, 시뮬레이션을 통해 이를 검증한다. 시뮬레이션 결과는 제안한 RPQC 제어방법의 타당성을 보여주고 있다.

• 시스템엔지니어링학술지
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• 제10권2호
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• pp.33-42
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• 2014

There have been growing demand of Light Rail Transit(LRT) which have a lot of advantages such as construction costs lower than the recent subway, reduction of operational costs, availability of line planning, operation of railway non-beneficiary region, flexible operations of trains, unmanned operation and also have eco-friendly advantages, it is now becoming urban railway systems when environmental issues have been highlighted all over the world. Therefore, RAMS(Reliability, Availability, Maintainability, Safety) Process and activities for effective implementation of light rail transit projects have become a very important element, and also the utilization of computerized tools to perform these more systematically and productively is sought after these days. In this paper, we have presented a plan that can support the RAMS activities by utilizing the function of the computerized SE(Systems Engineering) tool(CORE$^{(R)}$). Through support of the computerized SE tool, it would be possible more clear and efficient railway project execution.

• 한국철도학회논문집
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• 제3권3호
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• pp.154-160
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• 2000

The automatic/driverless operation which are great important techniques in metro railway are required to increase higher safety, greater reliability, and transport capacity. To satisfy such demands, we must have the system design and testing technique for the railway system operation. These techniques are related to the onboard train control and communication systems which include TCMS(Train Control and Monitoring System), ATO(Automatic Train Operation), ATC(Automatic Train Control), and TWC(Train to Wayside Communication). These sub-systems must be interfacing with not only each others but also the signal system on the ground. We tested the train control system on Test line that has been developed on the basis of the standardized type EMU for korea railway systems. This test line which is located in Sangju, have been constructed for testing 7 ＆ 8 line of Seoul Metro railway.

• 대한안전경영과학회지
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• 제9권6호
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• pp.9-17
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• 2007

This article addresses the question of how the operational architecture for a railway safety information system should be developed. A successful railway safety information system can be developed by fully reflecting the business process and needs at the enterprise level. To date, there has been minimal research effort towards the development of the operational architecture for a railway safety information system. To this end, a variety of enterprise architectures have been studied so far. In this paper, as an important guideline, DoDAF (Architecture Framework) is selected to be used in developing a railway safety information system. In particular, we propose a method to implement the operational architecture based on DoDAF.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1197-1198
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• 2007

According to the computerization of railway signalling systems, the safety demonstration and assessment of railway signalling system is very important. For this reason, railway signalling systems reflect the needs of methodology to assessment the safety. Then many studies of safety assessment methodology for railway signalling systems centering on the Europe, have been made continuously, and the requirements for safety acceptance are currently standardized by IEC. To develop and establish the safety assessment technology for railway signalling system in Korea, we are reviews the safety assessment activities for signalling system through the reviews of related std., case study and consulting by experts.

• 전자통신동향분석
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• 제36권4호
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• pp.23-33
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• 2021

Wireless communication for train control is an active research field. The World Railway Federation in Europe developed GSM-R, which integrates the GSM-based voice call standard and train control signals. To provide advanced railway services, the LTE-R wireless communication system was developed in Korea for passenger services and wireless image information required by the railroad industry. Recently, direct communication technology for autonomous train driving has been studied to decrease the driving interval, and research is being conducted on a hyperloop train control system that runs at a maximum speed of 1,220km/h in a subvacuum environment of 0.001 atmosphere. In this paper, we summarize the trends in wireless communication technologies used for GSM-R/LTE-R railway systems. For future wireless communication in railway systems, we discuss autonomous train driving and the hyperloop railway control system, define wireless communication technology, and discuss trends in domestic and foreign technologies.