• Journal of the Korean Society for Precision Engineering
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• v.29 no.6
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• pp.600-606
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• 2012

Upon investigation of the damaged wheels for high speed train it was determined that the damage was caused by rolling contact fatigue during operation of train. The major problems that railway vehicle system using wheel-rail has to face during operation of railway vehicle are rolling contact fatigue, cracks in wheels, cracks in rails and wheel-rail profile wear. If these deficiencies are not controlled at early stages the huge economical problems due to unexpected maintenance cost in railway vehicle can be happened. Also, If the accurate knowledge of contact conditions between wheel and rail can be evaluated, the damage of wheel can be prevented and the maintenance operation can save money. This paper presents the applicability of electro-magnetic technique to the detection and sizing of defects in wheel. Under the condition of continuous rolling contact fatigue the damage of wheel has continuously monitored using the applied sensor. It was shown that the usefulness of the applied sensor was verified by twin disc test and the measured damaged sizes showed good agreement with the damaged sizes estimated by electro-magnetic technique.

• Smart Structures and Systems
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• v.28 no.6
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• pp.827-838
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• 2021

The dynamic displacement is considered to be an important indicator of structural safety, and becomes an indispensable part of Structural Health Monitoring (SHM) system for high-speed railway bridges. This paper proposes an indirect strain based dynamic displacement reconstruction methodology for high-speed railway box girders. For the typical box girders under eccentric train load, the plane section assumption and elementary beam theory is no longer applicable due to the bend-torsion coupling effects. The monitored strain was decoupled into bend and torsion induced strain, pre-trained multi-output support vector regression (M-SVR) model was employed for such decoupling process considering the sensor layout cost and reconstruction accuracy. The decoupled strained based displacement could be reconstructed respectively using box girder plate element analysis and mode superposition principle. For the transformation modal matrix has a significant impact on the reconstructed displacement accuracy, the modal order would be optimized using particle swarm algorithm (PSO), aiming to minimize the ill conditioned degree of transformation modal matrix and the displacement reconstruction error. Numerical simulation and dynamic load testing results show that the reconstructed displacement was in good agreement with the simulated or measured results, which verifies the validity and accuracy of the algorithm proposed in this paper.

• Journal of the Korea Safety Management & Science
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• v.14 no.2
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• pp.23-33
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• 2012

Recent technological advances in the domestic railway industry have turned out to deliver a profound impact on the forefront of other industries as well. Furthermore, the introduction of the high-speed railway systems has made it possible to travel around our country in a day, thereby changing our life styles a lot. However, it has been well recognized that many factors can cause unanticipated accidents during the operation. One of the causes is known to be the human errors made by the train operators in locomotive cabs. The problem is getting more serious as the trains run at high speed. As such, the objective of this paper is on how to improve the work environment of the locomotive cabs. Our approach is based on the systems engineering methodology. Specifically, we first identify the context and scope of the problem to be solved. We then continue our effort in deriving the requirements set to accomplish the improvement. These results are utilized in constructing a computer-aided management system for test and evaluation intended for the improvement. The approach taken and the results obtained in this paper is expected to make a contribution on the route to keeping our nation's technologies on the competitive edges in the high-speed railway systems industry.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1436-1441
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• 2006

In this paper, Computer-aided Maintenance Equipments, which are being used in High Speed Line Train Control System, are applied to analyze failures in train control systems, resulting in long time delays of trains. It can be expected to extend and apply CAMS(Computer Aided Maintenance System) in the hereafter efficient operation and maintenance of high speed railway train control systems, by comparison between the analysis result of fundamental causes, from high speed railway train control system failure occurred during the operational process, and predictive result of failure causes, based on the recording data of CAMS when failures were occurred.

• Smart Structures and Systems
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• v.29 no.3
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• pp.421-431
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• 2022

Concrete slab cracks monitoring of modern high-speed railway is important for safety and reliability of train operation, to prevent catastrophic failure, and to reduce maintenance costs. This paper proposes a curvature filtering improved crack detection method in concrete slabs of high-speed railway via graph-based anomalies calculation. Firstly, large curvature information contained in the images is extracted for the crack identification based on an improved curvature filtering method. Secondly, a graph-based model is developed for the image sub-blocks anomalies calculation where the baseline of the sub-blocks is acquired by crack-free samples. Once the anomaly is large than the acquired baseline, the sub-block is considered as crack-contained block. The experimental results indicate that the proposed method performs better than convolutional neural network method even under different curvature structures and illumination conditions. This work therefore provides a useful tool for concrete slabs crack detection and is broadly applicable to variety of infrastructure systems.

• Journal of the Korean Society for Railway
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• v.2 no.3
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• pp.18-25
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• 1999

A high speed train named Korean High Speed Train (KHST) with its maximum operating speed 350 km/h is now under development. For the successful design of a quiet and comfortable high speed train, it is important to understand the general features of the noise and vibration characteristics of high speed train. This paper reviews extensively collected materials on the noise and vibration characteristics of existing high speed trains. Based on the noise and vibration characteristics of TGV systems, a simple indoor-noise prediction rule is proposed for the TGV-type high speed trains such as KHST The indoor-noise of KHST at 350km/h is expected to be larger than at least 71 dBA. Some important researches conducted for designing KHST during last two years under the G-7 project are also briefly introduced at the last part of this paper.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.4
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• pp.379-386
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• 2016

As well as to operate a high-speed rail, our country with capability to produce high-speed train has developed a number of techniques, such as for a riding comfort improvement, automatic diagnosis for major electrical or mechanical parts, on board measurement for catenary systems and noise reduction of running rolling-stocks are still under development. In this paper, we describe the current status of operation technologies not only traditional railway wireless communication systems but also Long Term Evolution systems which would be deployed as soon as possible, like as in Europe, China and the United States. In addition, we produced the domestic wireless communication networks for railway which KORAIL Corp. has been operating and the schemes and the plans of HSR field test for the fourth generation mobile communication which should be enforced by national research and development.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.337-339
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• 2005

The purpose of this paper is to compensate the voltage drop of the power system in the AC High-Speed Railway (HSR). Reactive power compensation is often the most effective way to improve system voltage drop. The suitable modeling of the electric railway system should be applied to the EMTP. the dynamic characteristics of 3-Phase Induction Motor in Electric Railway Systems is considered for precise modeling. it is shown through EMTP simulation that voltage drop can be compensated effectively by STATCOM.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.9
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• pp.1406-1410
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• 2015

The railway catenary systems consist of a complex structure, electrical and mechanical conditions are exposed to dangerous environment due to current collection between pantograph and catenary systems. These two types of conditions for the catenary systems are critically assessed for management and are becoming increasingly more dependent on reliable inspection system. In this paper, a new measurement system which enables inspection of catenary faults was studied and implemented. The system uses wavelength band of ultraviolet (UV) and IR (Infrared) to measure the insulation of corona and temperature of catenary wire. In order to determine the sensitivity of implemented system, the performance test such as distance detection range of UV camera and temperature resolution of IR camera were conducted, respectively. The field test of development system was also conducted in metro and high-speed line using mobile type UV and IR multi-composited measurement systems.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.51-56
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• 2002

A Korea next-generation high-speed rail system represents a typical example of large- scale multi-disciplinary systems, consisting of subsystems such as train, electrical hardware, electronics, control, Information, communication, civil technology etc. The system design and acquisition data of the large-scale system must be the subject under strict configuration control and management. The system therefore, must be developed using systems engineering that is a efficient and effective methodology to design such a complex system and manage its development. This paper presents the results from a computer-aided systems engineering application to the Korea next generation high-speed railway project. Especially, the focus of the study was on requirement management and PBS management.