• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1155-1160
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• 2011

The importance of broadband wireless communication implemented at subway tunnels is growing up. At 18GHz wireless video transmission system, the transmitter requires a digital modulation method. At subway tunnel, A 18GHz's influence of the multi-pass padding is strong. OFDM digital modulation that is strong for multi-pass padding is recommended. Duplexing methode uses FDD to transmit and receive broadband data at the same time. In the case of FDD we assign a private use channel each with the transmission at the receiving. In this paper, We implement multiple access wireless OFDM transceiver. We verified that one ground transceiver communicates with two car transceiver at the same time.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1008-1013
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• 2011

The importance of broadband wireless communication system at subway tunnels is growing up. At 18GHz wireless video transmission system, the transmitter requires a digital modulation method. At subway tunnel, A 18GHz's influence of the multi-pass padding is strong. OFDM digital modulation that is strong for multi-pass padding is recommended. Duplexing methode uses FDD to transmit and receive broadband data at the same time. In the case of FDD we assign a private use channel each with the transmission at the receiving. In this paper, We implement multiple access wireless OFDM transceiver. We verified that one ground transceiver communicates with two car transceiver at the same time.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.670-674
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• 2004

High-speed trains with the maximum speed of 300 km/h have started revenue services since April 2004. A large portion of the 'Kyung- Bu' line is comprised of tunnels or bridges, which may cause excessive noise in a vehicle. The vibration generated by the trains propagates into the structure of the tunnel and the vehicle and it can be radiated as noise inside the vehicle interior. This noise can usually be heard as low frequency structure-borne noise. Measurement of the noise and vibration inside the KTX vehicle confirmed that the noise comprises of frequencies below 250 Hz with a couple of broad peaks.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.466-471
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• 2003

The characteristics of a rock joint which influence the stability of rock mass structures, such as the cut slopes and the tunnels, are largely controlled by the conditions of the rock joint as well as its boundary conditions. Boundary conditions can be represented by assuming that the deformability(or stiffness) of the rock mass surrounding the joints is modelled by a spring with stiffness. A new direct shear apparatus is developed in this study, which adapts a servo control system using PID algorithm. This apparatus can be used to investigate the various aspects of shear characteristics of the rock joints at conditions of constant normal stress and constant normal stiffness and so on. It is possible that the behavior under the constant normal stiffness condition can be predicted by the normalized graphic method with results obtained from the tests in the constant normal stress condition.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.479-484
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• 2005

Comparison it analyed the tunnel travelling hour interior noise arresting quality of the inside and outside of the country high-speed vehicle from the research which it sees. In the interior sound arresting comparison objective vehicle of the tunnel travelling hour KTX vehicle from the research which it sees and it limited by the TGV vehicle of France and the ICE vehicle og Germany and the Shinkansen vehicle of Japan comparison it analyzed the interior sound arresting from the open field and the tunnel line. The tunnel passage hour interior sound arresting problem of the domestic KTX vehicle follows in the concreate track tunnel the ballast track tunnel and the interior sound arresting quality is appearing different.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.338-343
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• 2005

The Korean high speed train(KHST), developed since 1996, is presently undergoing commissioning tests on the high-speed track as well as on the conventional track since 2002. The purpose of the commissioning test is twofold: first to verify the performance of the train-set and equipments, and to demonstrate system reliability. Last December, KHST has reached the maximum speed of 350km/h and a number of data proving the performance of the train has been acquired. Among the data noise level and pressure variation in a cabin are important factors effecting passenger's comfort. Discussed in this paper are interior noise and pressure variation when the train passes tunnels during the 350km/h test.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.444-447
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• 2007

The free flow of fine bubbles generated by electrolysis and smoke flow in a space enclosed by fire were recently found to show the same tendency thus leading to the introduction of a research technique. The research experimentally models smoke diffusion and flow in parallel and slanted tunnels using the fine hydrogen bubbles generated by electrolysis in a water tank. Visualization laser with wavelength of 532nm and output power of 1000mW is used to visualize effectively the cross section of fine hydrogen bubble flows generated in a model tunnel.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.2195-2201
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• 2010

High concentration of carbon dioxide in subway cabin may cause various adverse effects on the passengers. Because carbon dioxide is produced by breathing of passengers, carbon dioxide concentration at rush-hours is extremely high. In most cases, the ventilation is not that easy for subway cars due to the high concentration of dust in tunnels. In this study, more practical way to control carbon dioxide in subway car was suggested. The decrease of carbon dioxide concentration was observed when the system was applied to a real subway car. The regenerative method for maintenance-free carbon dioxide control system was also suggested.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1000-1005
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• 2010

Ride comfort is an important factor for the development of a high-speed train. The aerodynamic force to a high speed train inside tunnels increases the car-body vibration and makes its ride comfort worse. In this study, the aerodynamic force is estimated through a CFD analysis using ADINA, and its car-body vibration and ride comfort are calculated for the aerodynamic force which acts on the side of the train. The numerical results show that the vibration is a lateral mode of the car-body and decreases the ride comfort. On the basis of this numerical simulation, more accurate simulation is necessary for the shape of tunnel and the lateral suspension system of a high speed train.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.2089-2094
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• 2010

The importance of broadband wireless communication implemented at subway tunnels is growing up. At 18GHz wireless video transmission system, the transmitter requires a digital modulation method. At subway tunnel, A 18GHz's influence of the multi-pass padding is strong. OFDM digital modulation that is strong for multi-pass padding is recommended. In this paper, Suitable to a subway wireless video transmission OFDM receiver is designed. OFDM receiver system has 6dB gaion because uses diversity of space diversity and MRC(Maximum Ratio Combining) diversity. The transmitter system use C&ITechnologies's transmitter board. IF frequency of receiver is 480MHz. OFDM modulation parameter is as follow, The bandwidth is 8MHz, The numuber of carrier if 2,000, The modulation methode is QAM16, The guard interval is 1/32.