• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.10
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• pp.993-1001
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• 2007

An analysis model has been developed to assess running safety of railway vehicle passing curves. By using ADAMS/Rail, a computer analysis has been conducted by changing various parameters according to the track conditions. Analysis results show as follows: A derailment coefficient of left wheel was increased according to increase of cant at low speed, while it was decreased as increase of cant at high speed. A unload rate of left wheel was also increased according to increase of cant at low speed, while it was decreased as increase of cant at high speed. A wear number of left wheel was increased according to increase of cant at all speed, but only at 35 m/s, it was decreased as increase of cant. A friction coefficient of left wheel was Increased according to increase of cant at all speed, but only at 35 m/s. it was decreased as increase of cant.

• Journal of the Korean Society for Railway
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• v.15 no.3
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• pp.244-250
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• 2012

In this paper, The next Generation High Speed Railway Inverter system using RCF-PWM(Random Carrier Frequency Pulse Width Modulation) was developed to reduce electromagnetic noise. RCF-PWM method is randomized the switching frequency in the range between Semiconductor switching devices' maximum switching frequency and minimum switching frequency, Simulation program has been built using MATLAB/Simulink to verify the validity of study. Finally, the simulation results of Next Generation High Speed Railway inverter system using the RCF method was compared with the conventional SVPWM method.

• Journal of the Korean Society for Railway
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• v.15 no.3
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• pp.231-236
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• 2012

In this paper, aerodynamic noise characteristics of high-speed trains were deduced from the beamforming method. First, pass-by noise of high-speed trains was measured by a microphone array system. This measurement suggested that the majority of the aerodynamic noise produced came from the bogie area, the pantograph and its cover, and inter-coach gaps. Then, beampower outputs of a position in high-speed trains were obtained from the beamforming method. By Fourier transform, sound characteristics of the position in the frequency domain were deduced from the beamforming power spectrum. From this study, aerodynamic noise characteristics from the major sources of high-speed trains were drawn.

• Journal of the Korean Society for Railway
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• v.10 no.6
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• pp.786-791
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• 2007

Aerodynamically generated noise is dominant when the train speed approaches 300km/h. This noise sources is caused by the turbulent flow separations or vortex shedding from the train structure. Experiments were performed to investigate the characteristics of aerodynamic noise sources generated from exterior of the KTX trains and HSR-350x, especially from the inter-coach spacing. Measurements of both the inside and outside of the cabin are carried out to investigate the characteristics of the noise. Effect of the size of the mud-flap has been investigated through an wind tunnel test and it has been found that the low frequency noise is strongly dependent on the size of the gap. Also performed is an array measurement to locate different noise sources from the high-speed train. spectral characteristics of exterior noise sources are examined.

• Journal of Korean Society of Steel Construction
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• v.18 no.1
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• pp.47-51
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• 2006

Measuring the track geometry of a high-speed railway is the most important task in track construction and track maintenance work. Measuring accuracy is particularly sign the formulation of the maintenance plan and in the assessment of the work quality, and because it can set the train speed limit. To determine the track geometry of a high-speed railway, it is important to use KNR's track recording coach (EM-120). According to the result of the spectrum analysis, noise near the 1-m wave band was found on the track recording data. A new filter was thus applied to remove the noise from the track recording data. A similar result can be acquired when this method is used in real track geometry.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.101-106
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• 2007

Noise pollution from a high speed train has been a serious social issue nowadays. Especially when a train speed exceeds 300km/hr, an aerodynamic noise level has been known to be increased based on 4-6th power laws. In this paper, a simple approach to evaluate the sensitivity effect on noise due to the speed change has been examination.

• International Journal of Internet, Broadcasting and Communication
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• v.8 no.4
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• pp.48-53
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• 2016

Noise and vibration pollution is emerging to people in high speed trains. And it is difficult to realization of eco-friendly railway system at noise problem. The railway internal noise is 73dB on average and over 80dB in the loudest section. In order to reduce noise, there are passive methods that are far from noise sources and theother active noise reducion method. In this paper, we propose a method of reduce noise by measure and estimate the noise condition of train environment using Bone-Conduction device. We use an anti-phase waveform for canceling of noise characteristic. With this new system, the noise from surrounding environments can be reduced.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.82-83
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• 2008

In the cases of high speed railway bridge, dynamic behavior analysis is important because of high passing velocity and moving load at the regular intervals, and the damping ratio is a major element in dynamic behavior analysis. In this paper, damping ratios were estimated by two methods and vibration type sections, and relationship between estimated damping ratio and representative value of bridge vibration. At the results, estimated damping ratio using all time of vibration were more stable then using only free vibration section. And in the case of using extended Kalman filter, estimated damping ratio were trend of growth by growth of representative value of bridge vibration. At last, it was shown that study about reliabilities of estimated damping ratios were need.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.882-888
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• 2008

The increase in logistics and the emergence of high speed vehicles are aggravating the noise problem, and disturbing large numbers of people. Therefore, growing attention is being paid to the creation and utilization of a noise map in order to grasp and predict the influence of noise, and to establish a policy that effectively reduces noise. However, so far there has been little progress in developing a predictive formula for railway noise, and a noise prediction program suitable for the domestic environment. Therefore, there is a need for a method to apply the overseas prediction formula to domestic railway vehicles. This study evaluated the prediction method, the result of which is similar to that of a real measurement, using a noise map. It also employed a commercial software program, SoundPlan, to predict noise.

• Journal of the Korean Society for Railway
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• v.7 no.4
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• pp.291-295
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• 2004

The Track geometry measuring on High-speed railway is the most important subject for the track construction and track maintenance work. Also the measuring accuracy is so significant part because it provides principle data for the maintenance plan and the assesment of working quality and can control the train speed limitation. From this point of view, it is very important to verify for the track recording coach(EM120) in KNR. According to the result of spectrum analysis, the noise near 1m waveband was found on the track recording data from EM120. So, New filter has been applied to remove the noise form track recording data. and it makes possible to acquire resembling result to real track geometry.