• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.7
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• pp.732-740
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• 2008

This paper presents vibration control performances and stability evaluations of railway vehicle featuring controllable magnetorheological(MR) damper. The MR damper model is developed and then incorporated with the governing equations of motion of the railway vehicle which includes vehicle body, bogie and wheel-set. A cylindrical type of MR damper is devised and its damping force is evaluated by considering fluid viscosity and MR effect Design parameters are determined to achieve desired damping force level applicable to real railway vehicle. Subsequently, computer simulation of vibration control and stability analysis is performed using Matlab Simulink.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.854-855
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• 2011

Active suspension technology of railway vehicles has received attention as the way to replace the current passive suspension. This paper deals with the dynamic performance of an active suspension system for a railway vehicle. To verify performance of an active suspension, the dynamic performance of the railway vehicle with active suspension system analyzed and compared with conventional suspension system by using the VI-rail program.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.2 s.107
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• pp.156-162
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• 2006

For the reduction and efficient management of railway noise, first of all prediction of railway noise is necessarily requisited. Many studies for prediction of railway nearby noise have been accomplished. But it is impossible to predict easily and exactly for the Korean Railway, because the acoustic powers for each rolling stock operated in Korea have not been built yet. So in this study, Prediction model equation for environmental noise for Korean rolling stock Saemaeul was suggested using SEL of engine and rolling noise component separately. Finally for the validation of prediction equation, the predicted result was compared to the measured.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.5
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• pp.543-550
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• 2011

The development of railway vehicles such as new mechanism of railway vehicle or design parameters of suspension have been used the application of scaled roller rig to the study of railway vehicle dynamics. In this paper, the critical speed was compared between full scale and 1:5 scale of numerical model. And to verify the simulation results, the critical speed was confirmed using the 1:5 scaled roller rig. According to the results, we expect that the developed roller rig will be used in the study for the dynamic characteristics of railway vehicle.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.8
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• pp.1262-1268
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• 2015

I In power transmission systems, voltage changes continuously as reactive power is whether over supply or shortage. Reactive power produces in generators and consumes in transmission lines, and loads. Voltages at end points of transmission lines rise which is called Ferranti effect. Excessive voltage rising can reduce transmission equipment life, the voltage rising is usually permitted within the limit of 10%~30% excess. Shunt reactors are installed in transmission lines to put a curb on voltage rising. In this paper, we tried to do modelling for shunt reactor configuration types which are no grounding, grounded and grouded neutral reactor. Simulation are carried out for reactor magnitude for compensating transmission line capacitance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.191-196
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• 2014

For the large scale of electricity consumer, since the price for the electricity consumption depends on the peak power, the issue for peak power reduction have been being studied widely. Electric railway systems, which is one of the most representative large scale of loads, also has assignment to reduce the peak power since they have high peak power and low energy consumption load characteristics. In the aspect of the economic operation through reduction of peak power, this paper proposes a novel algorithm for power management system in electric railway systems using energy storage.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.371-376
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• 2005

For the reduction and efficient management of railway noise, first of all prediction of railway noise is necessarily requisited. Many studies for prediction of railway nearby noise have been accomplished. But it is impossible to predict easily and exactly for the Korean Railway, because the acoustic powers for each rolling stock operated in Korea have not been built yet. So in this study, prediction model equation for environmental noise for Korean rolling stock Saemaeul was suggested using SEL of engine and roiling noise component separately. Finally for the validation of prediction equation, the predicted result was compared to the measured.

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.638-644
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• 2012

In this study, we numerically estimated available and unavailable time of conventional railway by examining 60% which is known as average range of track utilization efficiency. We also estimated track repair time for maintenance which is the main factor of making track utilization change and analyzed appropriate estimated time. The railway's safety should be guaranteed by appropriate railway operating plan and by adequate rail facilities maintenance. At the same time, daily railway train 'Dia's recovery power should be reflected to the management plan. Considering these factors, we examined mechanical equipment and the national rail network in order to rationally estimate track repair time of the maintenance and to secure spare time in case of train delays. It was found that track utilization efficiency was more or less 60%.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.4
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• pp.739-746
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• 2016

The real-time railway safety monitoring and control system is for prevention of safety accidents, and this system adopts DDS (Data Distribution Service) standard based data transmission method to support integrated management of data from existing on-site safety detection devices. In this paper, we introduce the design of DDS-based data specification from on-site signal equipment on the conventional railway. For this, we (1) design UML data model of KRS SG 0062 standard which defines existing data specification, (2) define DDS Topics for DDS transmission and map KRS model to DDS Topic model, (3) suggest data transformation rules and (4) design network control QoS polices. In addition, we analysis actual on-site log data and validate our data specification design. DDS-based data transmission enables data compatibility among on-site devices and the real-time railway safety monitoring and control system, and allows efficient network management for a large amount of data transfer.

• Geomechanics and Engineering
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• v.21 no.2
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• pp.179-186
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• 2020

Investigating damage potential of the railway infrastructure requires either large amount of case histories or in-depth numerical analyses, or both for which large amounts of effort and time are necessary to accomplish thoroughly. Rather than performing comprehensive studies for each damage case, in this study we collect and analyze a case history of the high-speed railway system damaged by the 2004 M6.6 Niigata Chuetsu earthquake for the development of the seismic fragility curve. The development processes are: 1) slice the railway system as 200 m segments and assigned damage levels and intensity measures (IMs) to each segment; 2) calculate probability of damage for a given IM; 3) estimate fragility curves using the maximum likelihood estimation regression method. Among IMs considered for fragility curves, spectral acceleration at 3 second period has the most prediction power for the probability of damage occurrence. Also, viaduct-type structure provides less scattered probability data points resulting in the best-fitted fragility curve, but for the tunnel-type structure data are poorly scattered for which fragility curve fitted is not meaningful. For validation purpose fragility curves developed are applied to the 2016 M7.0 Kumamoto earthquake case history by which another high-speed railway system was damaged. The number of actual damaged segments by the 2016 event is 25, and the number of equivalent damaged segments predicted using fragility curve is 22.21. Both numbers are very similar indicating that the developed fragility curve fits well to the Kumamoto region. Comparing with railway fragility curves from HAZUS, we found that HAZUS fragility curves are more conservative.