• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1140-1141
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• 2006

Maglev is a non-contact traffic system in which cars are supported by magnetic force instead of wheels. This is a ground-breaking traffic system providing superior environmental friendliness and cost efficiency due to the minimal noise and vibration offered by its non-contacting nature. We study the present specification and performance of the low speed urban maglev system in Korea and other countries. After set up the test line, to success the "Commercialization of Korean Urban Maglev System" project, we establish proper requirement of maglev system in Korean environment on base of "Daejeon National Science Museum Maglev Establish Project".

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1109-1111
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• 2006

Tilting trains are now an established feature of railway operations throughout the world. For intercity traffic, tilt provides operators with increasing speeds, and therefore enhanced competitiveness, on existing routes where insufficient traffic or a lack of funds precludes the construction of a dedicated new high-speed railway. Appling the tilting train, we can expect 30% of speed up on existing lines, but the stability of the electric current would be low because of tilting the train. Also, the spark between the catenary and pantagraph cause environmental problems such as noise, radio wave malfunction. Therefore, the tilting on pantagraph for the power suppling device is very essential for stable electric power supply.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.442-446
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• 2009

As the railway transportation is getting faster and its operation speed has increased rapidly, its signal control has been complicated. For real time signal processing it is very important to prohibit any critical error from causing the system to malfunction. Today, most of the railroad's controling communications between wayside and train are made in one way. Therefore, by using a forward error correction technique, which receiver can actively correct the signal error, we can increase the performance and the stability of the railroad signaling system. In this paper, we introduce low density parity check(LDPC) that is used by next generation wireless communications and DMB technique. We verified that we can achieve low bit error rate(BER) in high signal to noise ratio(SNR) by using LDPC.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.541-548
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• 2008

Active application of auger-drilled piling is expected in Korea considering its advantage in noise and vibration problems against driven piling and its cost-effectiveness in comparison to the cast in-situ piling. The current design practice being used in Korea is adopted from the Japanese one, however the equipment and construction procedure is modified for the geotechnical conditions and construction circumstances in Korea. Therefore there is an urgent need for the establishment of the rational design criteria for the auger-drilled piling in Korea. As the preliminary work for the establishment, this paper presents the current practice in Korean railway constructions. Design criteria of Korea Railway Network Authority are introduced and its characteristics and the problems are described. Application cases of auger-drilled pile to railway construction are introduced as well.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.424-426
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• 1999

In this paper, the design characteristics, the manufacturing process and the results of performance test on the AC traction motor for urban transit standard E.M.U which is newly developed with applying standardization specification will be introduced. It is reviewed that the design and performance analysis on conventional motors considering system correlation and design constraint and the design optimization through an analysis of electro-magnetic, thermal and dynamic properties. The properties of factory products manufactured by 200 Class VPI process exhibit a excellent performance with a lower noise and vibration, higher efficiency and power factor etc.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2360-2362
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• 2005

전기철도 분야에서 전자기파에 의한 환경영향 평가는 중요한 요소가 되고 있으며 급전시스템, 신호시스템, 차량시스템 등으로 나누어 각각에 대한 전자기파 환경 영향에 대한 평가에 관한 사항이 연구 중에 있다. 특히 신호시스템 중, AF(Audio Frequency)궤도회로는 철도차량과의 빈번한 통신을 통하여 철도차량 제어에 많은 역할을 담당하므로 잡음에 취약하고 오동작은 사고로 직결되므로 이러한 잡음에 대한 평가는 중요하다 할 수 있다. 본 논문에서는 전기철도차량과 신호시스템 중 AF궤도회로와의 전자기적합성을 입증할 수 있는 고조파 분석을 통한 전도성잡음의 시험 및 평가에 대한 방안을 제시한다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.10
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• pp.1069-1077
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• 2015

In tunnel excavation using blast, the wire saw rock cutting method generates a discontinuity perimeter around the center cut, and thus prevents blast vibration propagation to reduce vibration and noise. Therefore, the method is expected to be easy to use and economical compared with other methods. In this paper, the cutting mechanism of wire saw in tunnel excavation is investigated. A model describing the changes in cutting depth and wire saw shape inside a rock during cutting is established and validated for this purpose. Through a simulation using the model, the important characteristics of wire saw cut are investigated, and the influences of cutting conditions, such as wire saw tension, wire saw speed, feed speed, depth, and diameter of boring, on cutting performance are also examined. A method to improve the cutting performance is proposed based on the results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.10
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• pp.1014-1023
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• 2008

Subway electric trains need to be faster for accommodation of long distance passengers. The faster run of the existing trains results in deterioration of ride quality due to noise and vibration. To reduce the noise and vibration of the electric train, a running test of the electric train was performed and an ADAMS/Rail model was set up to verify the running test results. The experimental results show that the sources of the cabin noise and vibration basically comes from the irregularity of the railroad track and the deterioration of the connection part between cabin and bogie. Consequently for mitigation of noise and vibration of the electric train, the redesign of the center pivot with softer stiffness and the minimization of rail irregularity are necessary. the frequent maintenance of the train will lead to better comport.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1134-1139
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• 2007

In recent years, public complaints about railroad noise by KTX and Ordinary train are increasing. Restriction of railways uses same standard without distinguishing the type of railways. According to the type of railways, the frequency characteristics of emitting noise is different. Therefore it is requested to know how vary the public response to each types of railway. The noise annoyance to 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 2.9dB(A) to ordinary train.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.907-910
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• 2008

The wheel radiation noise characteristic of Korean tilting train(Hanvit 200) on curved rail under the field test conditions is analyzed in this paper. The test railroad track was selected from Seodaejon to Songjeongri in Honam line. $5^{th}$ and $6^{th}$ car are decided to measure radiation noise level among a train of six cars. The test subject curve radius executed from R400, R500, R600, R700 and R800 segments. The speed of test trains when from R600 and R800 curves existing operation speed and speed up 20% of existing speed. On curved rail at the time of operation speed of Hanvit 200 trains from below 95km/h wheel radiation noise level at $94dBA{\sim}99dBA$, the operation speed from between $100km/h{\sim}144km/h$ wheel radiation noise level at $100dBA{\sim}106dBA$.