• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.457-462
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• 2011

The sidewall of the HEMU-400x consists of two parts. One is the multi-layered structure including aluminium extruded panel and the other is the double glazed window. When the train runs in a tunnel, the equivalent sound insulation performance of the side wall significantly influences the internal noise levels. In aspect of the sound insulation strategy, it is important to make two parts have similar performance. In this study, the intensity sound transmission loss (ITL) is measured on the specimens of the two parts. Mass law deviation (MLD) is considered in order to compare the sound insulation performance of the two parts in respect of the weight. Contribution of each part to the sound insulation is analyzed and the sound insulation strategy is investigated to reduce the interior noise.

• Korean Journal of Optics and Photonics
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• v.11 no.2
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• pp.102-107
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• 2000

We propose a new scheme for generating a pedestal-free, femtosecond soliton pulse train by utilizing quasI-adiabatic high order soliton pulse evolution in dispersion decreasing fiber in conjunction with the intermediate pedestal suppression stage. Compression factor over 280 was achieved from lOGHz sinusoidal input, to 176 is soliton pulse train. train.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.467-472
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• 2002

The railway signal ing system consists of several vital computerized equipments. Now the project for development of signal ing system for the next-general ion high-speed train is progressed according to the consortium. The developing signal ing system by this project, kTCS(Korean Train Control System), is composed of kTCS-CTC, kTCS-IXL, kTCS-ATC and etc. The KTCS signaling has to be operated as a integrated system by interface between each signaling. To achieve these, communicat ion protocols between each signal ing have to be designed and message codes are defined. In this paper the configuration of integrated kTCS system and designed communication protocol is presented.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1259-1263
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• 2006

The inter-coach spacing is one of the most important sources of the aero-acoustic noise of a high-speed train. When fluid at high speed flows over an open cavity, such as the inter-coach spacing, large acoustic pressure fields inside the cavity are produced by fluid/structure interactions at the downstream end of the cavity. In this study experiments were performed to investigate the characteristics the aero-acoustic noise generation from the inter-coach spacing of a high-speed train. Results of the measurement confirmed that the noise generated from the gap between mud-flaps are strongly dependent on the size of the gap.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1988-1998
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• 2008

Performed was a survey to find the level of interest on passenger services using IT and smart sensor technology in connection with High Speed Train development in Korea. The survey respondents were sampled from the KTX passengers, KTX crews, Korail employees, IT or sensor experts, and rolling stock experts. The results of the survey were categorized as importance, urgency/necessity, importance vs urgency/necessity, improvement measure, preferable activities based on the trip length, and inconveniencies. By analyzing the results, service items that can be implemented to the High Speed Train were recognized. The results showed that a passenger tends to expect to have his/her comfort and convenience, an attendant safety and serviceability, a Korail employee information provision and serviceability, an IT/sensor expert technological implementation done, and a rolling stock expert implementation done in practical level.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1143-1147
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• 2008

This test is performed to reduce slip/slide which are generated from VVVF inverter. when the adhesive force between wheel and rail is not ensured, slip/slide are mainly originated. In this paper, we carried out real test adopting acceleration changes to find optimized method minimizing the amount of generation of slip/slide. Through this real test, we obtained optimum result on reducing slip/slide and especially focused on decrease in slip. This method is currently applied to real train.

• Archives of design research
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• v.17 no.3
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• pp.123-132
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• 2004

This paper shows a study on the "Korean High Speed Train Design" method, its design process and the result in the form of aerodynamic optimal exterior design development of a prototype test train(HSR 350${\times}$). It was developed from 1996 until 2002, six years long in R '||'&'||' D project titled "Development of High Speed Railway Technology" The end result of the project is a prototype test train, which has two power cars, two motorized trailers and three trailers, had been tested successfully in the year 2003 to the highest speed limit 380km/h on high speed line. The improved conceptual design work of a new commercial train and next generation's train is also performed for future needs.uture needs.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.11 s.254
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• pp.1472-1478
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• 2006

Double-deck train has been attracted growing attention as next generation transportation around metropolis because of high passenger carrying capacity. To develop high-speed double-deck train with low operational costs, the carbody must be designed as light as possible. In addition, the carbody must be strong enough to ensure the safety of passengers. To meet these design requirements, we perform systematically weight minimization that determines thickness of aluminum extruded panels of the carbody. First, to reduce the design variables, we carry out the screening process that select sensitive or/and important design variables through design exploration. Then, weight minimization is accomplished under multi-loading condition such as vertical, compressive and torsional loads, while satisfying strength constraints of the design regulations. Finally, the result of design optimization is discussed by comparison with its initial design.

• 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.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.485-490
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• 2005

With the historical opening of the express rail, Korea has joined the league of France, Japan, Germany and Spain and entered into the super high-speed train era. Opening of the express rail will not only bring about enormous changes to the lives of Koreans, but it will also have a huge influence on the economic, social and cultural aspects of the country. With construction of the Seoul - Busan KTX line, railway passenger transportation capacity and freight transportation capacity will increase. Fast, safe, convenient and environmentally friendly, the express rail is a product of the latest technology and will secure its position as the newest and most preferred method of transportation for the next generation. As the traffic noise, train noise from KTX will become a social problems with the acceleration of speed and increase in the lines. In order to predict the train noise propagation from KTX, this paper presents the sound source system, the calculation model and the scale model experiment. Noise level unit patterns of a KTX that take the rolling noise, the motor noise and aerodynamic noise into consideration are simulated by the scale model experiment and numerical analysis.