• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.158-160
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• 2008

Safety critical systems are those in which a failure can have serious and irreversible consequences. Nowadays digital technology has been rapidly applied to critical system such as railways, airplanes, nuclear power plants, and vehicles. The main difference between analog system and digital system is that the software is the key component of the digital system. The digital system performs more varying and highly complex functions efficiently compared to the existing analog system because software can be flexibly designed and implemented. The flexible design make it difficult to predict the software failures. This paper reviews safety standard and criteria for safety critical system such as railway system and suggests development methodology, ordering management and assessment process for railway software with more detail description.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.1
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• pp.40-47
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• 2002

This paper describes a re-adhesion control method for the Korean High-Speed Train (KHST) with parallel induction motor drive. To keep a traction efficiency and to improve vehicle maintenance, the adhesion characteristics between wheel and rail are analyzed. Also the re-adhesion controller is designed as the subsystem of induction motor vector control. In order to verify performance of the proposed control techniques, the simulation is executed by train model and a downscaled re-adhesion control simulator is utilized. Both simulation and running test results show that good re-adhesion characteristics are obtained.

• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.286-288
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• 2003

Accidents at level crossing where railways and roads cross cause many casualties because of collision of cars etc and it also has a risk of the 2nd accident of trains. it is the most vulnerable point in the railway safety. Fundamental solution for accidents at level crossing is making the crossings cubic. but it can't be easily progressed because of environmental and financial difficulties. every kind of anti-accident measures are being strived for. one of the strived results is level crossing obstacle detector which automatically detects obstacles like defected cars etc in the middle of level crossing and transmits the information of obstacles to the approaching train. However present level crossing obstacle auto detector needs high expenses to be installed and has difficulties that lenses of beam transmitter, beam receiver should be cleaned in snowing winter. this document reviews level crossing obstacle auto detector using ultrasonic sensor to measure these difficulties.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.244-247
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• 2006

Railway is superior to the other land transportation systems in aspects of energy efficiency and environmental problems. Energy efficiency and environmental problems are not considered during a preliminary feasibility study. Investment for railway is low because of low B/C in the economical efficiency analysis during the preliminary feasibility study. The body of this paper studies the data which can reflect environmental problems an assessment of environmental impact. Investment for railway would be higher when main environmental elements are considered before the choice of the railway lines.

• Journal of Applied Reliability
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• v.10 no.4
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• pp.237-250
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• 2010

Railway safety aims to ensure that railways take appropriate action to limit the risk of injury to persons or damage to property, to acceptable levels. Accreditation system specifies railway safety requirements to be included in a railway safety management system by any organization seeking to demonstrate the ability to control the processes that determine the acceptability of railway safety activities. The objective of this research is to investigate the international accreditation system for railway safety management. The yield information is quite valuable to operate collaborative processes with all interfacing transport operators and undertakings to facilitate risk control across the railway system.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2204-2205
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• 2011

ICT의 급속한 발전과 더불어 철도 차량에 대한 멀티미디어 정보를 제공하고자 하는 연구가 활발하게 진행 중이다. 이러한 멀티미디어 정보를 철도 차량에서 제공하기 위해서는 표준규격에 대한 연구가 보다 시급하다. 철도 차량용 멀티미디어 시스템을 위한 기반 기술은 국내외 적으로 부분적으로 개발되고 있다. 특히 IEC에서는 이러한 멀티미디어 정보제공을 위한 표준규격 제정을 서두르고 있다. 본 논문에서는 IEC TC9에서 추진하고 있는 철도차량용 멀티미디어 시스템에 대한 규격을 살펴보고, 향후 철도차량용 멀티미디어 시스템의 표준규격의 나아갈 방향을 제시한다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.12_13
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• 2009

Recently, TTX(Tilting Train eXpress) has operated test. Electric railways, including the TTX, have electric problems(harmonic etc) that could bring about serious accidents.. Thus, TTX's electrical problems also need leading studies because the new Korean TTX will operate earnestly in 2012. In this paper, electrical signals in TTX operation were detected to analyze electrical harmonic. The electrical harmonics considered operation modes triparted(coasting, acceleration, braking) were analysed and evaluated.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.201-203
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• 2007

Safety critical systems are those in which a failure can have serious and irreversible consequences. Nowadays digital technology has been rapidly applied to critical system such as railways, airplanes, nuclear power plants, vehicles. The main difference between analog system and digital system is that the software is the key component of the digital system. The digital system performs more varying and highly complex functions efficiently compared to the existing analog system because software can be flexibly designed and implemented. The flexible design make it difficult to predict the software failures. This paper reviews safety standard and criteria for safety critical system such as railway system and suggests software development methodology for more detail description.

• Journal of the Korean Society for Railway
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• v.5 no.1
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• pp.32-39
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• 2002

As most railways are gradually electrified with modernized electric cars, the demand for catenary wires and their facilities are also increased. Catenary Wires are exposed to the marine area with air-borne salt or severely polluted industrial area with much corrosive emission gases depending on the locations. Corrosion of catenaty wires can make their actual lifetime shorter than that originally designed. Thus, the messenger and ACSR wires, kinds of catenary wire system, were investigated with respect to corrosion, which include new and used ones collected at the field. Tensile strengths and elongations appeared to decrease when the wires were exposed to corrosive environments. The amount of decrease was more prominent as environmental conditions became more corrosive. They are also vibrated with some amplitude everytime pentographs touch contact line. The frequent cyclic load on the wire may result in a fatigue damage. Surface damage by corrosion can make fatigue crack initiate with ease. In the present study, the fatigue life of the used wire was measured 50 to 60% compared with that of new one in average.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.773-777
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• 2004

The variable-gauge wheelset drives on the variable railways. It doesn't need to replace or move the carriages to another bogie parts. This paper is for dynamic analysis of the variable-gauge wheel set. 3D-Virtual Mock-up. program was developed to verify the operating mechanism and understand dynamic characteristics for German RAFIL- V variable-gauge wheel set. When the system is going through the width-variable railway, its safety depends on the stiffness and velocity. So the numerical and contact model of this system were developed. This solution is useful to analyze dynamic characteristics for variable-gauge wheelset.