• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.3
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• pp.335-344
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• 2008

In recent years, public complaints against railroad noise by KTX and Ordinary train have been rising. Regulation of railways noise uses same standard without distinguishing the type of railroad cars. According to the type of railroad cars, the frequency characteristics of emitting noise is different. Therefore it is requested to know how the public response vary to each types of railroad cars. The noise annoyance from three types of trains(KTX, electric train, diesel train) was analyzed by jury evaluation test for assessing the effect of frequency characteristics. The numerical results by a semantic differential method showed that annoyance response to three type of trains depended on the frequency characteristics. As a result, this study proposed that the KTX could have a bonus level of maximum 2.9 dB(A) compared to ordinary train.

• Explosives and Blasting
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• v.20 no.3
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• pp.59-71
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• 2002

The points of this design case are the planning and excavation method of a new double-tracked railroad tunnel which is approx. 11∼22 meters apart from existing single-tracked railroad tunnel. For the optimum excavation method some needs are required in design stage, such as the reduction of noise and vibration, public resentment, damage of buildings and construction costs. Hence the estimation and application of allowable noise and vibration criterion is important. The ground coefficient (K, n) of this site is determined by field trial blasting. The excavation method is chosen to satisfy the allowable noise and vibration criterion. In addition, in order to ensure the stability of existing single-tracked railroad tunnel, the instrumentation of maintenance level is accompanied during the construction stage. As a result of this design condition, central diaphragm excavation with line drilling and pre-large hole boring blasting is applied to the area within 15 meters apart from existing tunnel. And above 15 meters apart, pre-large hole boring blasting is designed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.85-86
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• 2006

It presented the approach method for the station braking noise present condition and a braking noise reduction plan escape of the KTX train. The research which it sees the technical ground it will be able to accomplish the station braking noise reduction of the KTX vehicle with base the questing matter where the escape one thing is big there is a possibility of doing.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.635-641
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• 2001

This study introduces the basic concepts of the vibration reducing methods and presents a case study of 'A' apartment construction site which located nearby railroad. The site is only 60m away from the railroad. Therefor much noise and vibration damages could be expected during train or any other transportation's passing. Especially, the first and second floor may suffer much vibration with the low frequency radiation noise from the walls and floors. This study estimates the noise level of indoor area by measuring the vibration of indoor walls and floors. From this result, vibration barrier, as a method to reduce the noise level which exceeds proper standard value, was attempted to protect vibration transmit from the railroad.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.625-629
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• 2014

For the purpose of the acoustic performance evaluation of noise reduction device(NRD) installed at the top of noise barrier for further decreasing of noise level of 400km/h class high-speed railroad(HEMU), the acoustic performance test method using speaker instead of really running railway vehicle was suggested in this paper. For this, noise source location and frequency spectrum of HEMU was analyzed through the field noise test. These data were used for the determination of speaker's installation positions and frequency correction values applied to the speaker noise source. And, 400 meters long NRD was installed at the site where HEMU will be running at a speed of 400km/h. Finally, the outdoor speaker test with and without NRD showed that this NRD could decrease noise level even more than 3dB(A). In the future, the acoustic performance results of NRD conducted with speaker test will be compared with that of field test for HEMU running at a speed of 400km/h.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.125-130
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• 2014

High speed railroad car and high-rise apartment with development of railway technology cause different problems of noise contrary to the previous generation. It is the most efficient noise reduction countermeasure but we studied that is the way on noise propagation with sound proof wall or sound proof tunnel around railroad. But if it were railroad on bridge, additional cost which is more expensive than installing one on the ground is needed. So sound insulation material considering reducing weight of recent soundproof facilities must be selected. It is in this study that predicted and analyzed acoustical and structural effect for noise reduction by installing soundproof tunnel. If it were departmentalized into additional study, could be able to expect noise reduction effect of sound proof tunnel establishment on the bridge.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.265-272
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• 1998

In this paper, the intoner noise reduction for subway railroad vehicles was studied by improving transmission loss of carbody panels and side doors, and on-line tests were conducted to examine the exterior noise levels at various running conditions. Also the transmission loss for design candidates of the carbody specimen was measured in two reverberation rooms. From the results of the tests, side door gap is the most dominant factor affecting the Interior noise level of subway railroad cars with a sliding typed side door. The next one is revealed to transmission loss of a floor panel. To improve the transmission loss of the carbody, many activities were conducted such as, treatment of resilient and sound-absorbing materials and reducing the gap of the side door by adopting a brush and rubber, etc. The estimated interior noise level for modified car which is designed with improved carbody panels is lower than original car by about 5㏈.

• Journal of the Korean Society for Railway
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• v.19 no.3
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• pp.271-279
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• 2016

Pantograph aerodynamic noise is a major cause of noise that occurs when a train is traveling at high speeds. In this study, in order to analyze the contribution of pantograph aerodynamic noise, real train tests using HEMU-430X were carried out. In order to analyze the frequency characteristic of the noise of the pantograph in an actual vehicle, a sound field visualization has been carried out using a 144-channel microphone array at train speeds of 350 and 400km/h. As a result, it was confirmed that the low frequency noise in the 250~400Hz bandwidth provides the main contribution to the pantograph noise. And, in order to estimate the noise contribution of the pantograph, the noise level difference between cases in which the pantograph is ascending and those in which it is descending were compared in single microphone experiments. The frequency analysis in the single microphone tests showed that the bands of 315~400Hz and 1000~1250Hz are the main frequency characteristics of pantograph noise. These results show quite good agreement with those of previous studies and with results of sound field visualization.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.1-5
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• 2005

High-speed trains with maximum speed of 300km/h, named KTX, have started revenue services since April 2004. Is becoming big problem where currently the KTX train because excessive braking noise at a station platform. The KTX braking noise follows in operating mode of KTX train and important railroad station where the quality appears different, the quality against hereupon from the commerce vehicle from the research which it sees it executes and comparison to analyze.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.89-101
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• 2006

This study is a part of ???A study of the community noise:new guideline and policy' which have three main topics and ten sub-topics. Accordingly this part deals with a transpotation noise specifying road traffic ,railroad and aircraft noise, respectively. At first, the ,roadside traffic noise of whole country in 2004 ,22 major cities of total 29 was exceeded the envionmetal noise standards, 55dB(A) at night time ,therefore 24 milion people ,52.4% of korean, who reside at roadside estimates to be exposured the basic problems of this serious noise polluation comes from:: i)It's very limited noise mitigation measures against to continuously increase the number of automobile yearly. ii) and at beginning of road design, It has been neglect to introduce the anti-noise design and layout of road structural scheme as gadient,cutting and viaduct,embankment and zonning of roadside land-buffer area and also re-designation of noise sensitive areas,etc. Secondly ,concerned with the railroad trafffic noise, a inhabitants who are over the envionmetal noise limits,70dB(A), 65 dB(A) in day and night for 34 locations of mayor cities was exposured of 167,000 and 329,000 respectively. With the development of noise mitigation schemes in line with this study it is likely that noise monitoring system needs new installation as well as common use of noise assessment index with $L_{MAX}\;and\;L_{EQ}$. Lastly,noise complaints of millitary aircraft has been rapidly increasing ,so 2.9%(1.4 minion) person demands a compansation of \2,133 billion complying with their requirements we suggest to minimise the airport noise that is to develop of noise abatement procedure ,to make new noise index, to increase budget for house insulations and also to more increase of those the noise monitoring system and to unify the management etc.