• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.887-890
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• 2007

The low frequency noise, including infra-sound is known to affect human physiology and psychology. Guidelines and measurement method of low frequency noise has been introduced in several countries in order to evaluate low frequency noise. In this work, low frequency characteristics of Daejeon subway was investigated in terms of the noise level and spectrum in the interior of running subway car and the subway station. The interior sound pressure level of the passenger car was between 60 and 102 dB in the frequency range of $1{\sim}250$ Hz.

• Korean Management Science Review
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• v.14 no.2
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• pp.81-90
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• 1997

Network approach is used to find the shortest paths and transportation time between the subway stations in Seoul, Korea. Because of transfer stations, we reconstruct the subway network to compute the shortest routes and corresponding transportation times. The reconstructed network is useful to obtain desired information because it can handle the transfer time between tracks. Time and route information about the subway system is obtained and it will be displayed in the subway guide board at each station. Then, all passengers can have the information of shortest route to a destination and corresponding transportation time.

• Journal of Korean Society of Transportation
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• v.4 no.1
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• pp.28-40
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• 1986

Accurate subway demand estimation which is essential for better route selection can be achieved by the exact definition of the influence sphere of subway station. The influence was derived implicitly from the analysis of access time to the station for the cases of Seoul. Access time distribution was investigated by trip purposes, by age, by income, by sex, by travel distance, by kinds of thickets, by the location of station for the analysis of relationship between access time and socio-economic characteristics or urban structure. The difference of average access time between direct access trip and transfer trip which is found 8.6 minutes and 6.1 minutes respectively also investigated. The small difference implies poor transfer system of Seoul subway. 83.1% of subway users are coming from the distance of 10minutes' walk and average access time is 7.8minutes as a whole.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.1084-1092
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• 2005

Various urban transport policies have an effect on urban transit riderships. This study reports variations of metropolitan subway travel patterns affected by an enormous change in bus routes and transfer discount policy between subway and bus mode conducted by Seoul city in July 1st of 2004. In an effort to see the difference between the before and the after policies, two datasets are prepared. Firstly, on a daily bassis, an origin-destination trip table of May of 2004 is used. Secondly, on a daily bassis, an origin-destination trip table of August-September of 2004 is used as a counter measure. Even if seasonal variation was not considered. there were increasing riderships of about 0.25 million on a daily basis. Subway line 2 and 7 have an important role in changes. The effects or system changes, however. largely varied on location and subway line numbers.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.208-213
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• 2007

Pantograph is set on the roof of Subway. This plays the role of staying proper current on Subway when Subway is running or not. Pantograph includes Slider. Slider is most important part of Pantograph because this part is used to receive current from Contact Wire by dynamic interaction with Contact Wire. In general, material of Slider is steel, copper, or carbon alloy. Especially, SEOUL METRO uses Slider of sintered cualloy, but there is problem. This Slider causes over wearing during rainy season. We should reduce wearing between Contact Wire and Slider. Reducing this wear is most valuable technology in Subway system. I performed experiments to find out the best way that reduces the wear. I can find the best way as I change the rate of the alloy.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1475-1480
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• 2007

Numerical analysis has been conducted to simulate pedestrian flow in the model of two-storied subway station. Because almost all the subway stations are two or three storied structure, simulations are conducted for the passengers those who get off the train and pass the wicket. Passenger flow analysis is very important factor to design the station and also to manage the operation of subway system. In the subway station, pedestrians move to the horizontal directions as well as vertical ones. Therefore, to consider the movement of pedestrians is necessary for the guarantee of safety and conveniency. As the up and down floors are connected with step, escalator and elevator, the entire movements in the multi-storied station should be simulated as like a 3-dimensional flow. Numerical schemes for the directional sweeping are developed to prevent the dependency on physical structure of station and to determine primary direction and secondary one. By using the developed program, we compared the simulation results of the effects of the location and size of exit and elapsed time.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1313-1318
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• 2007

Recently, the terror frequently has taken place for unspecified individuals as modern society is complicated. Especially, in case of a subway carriage fire as Daegu subway fire, because smoke spread path usually coincide with passenger's evacuation path, it will reduce visibility and can cause fatalities by asphyxiation. This study performs not only fire simulation with CFAST V6 but also evacuation simulation with EXODUS V4 for the purpose of taking measures for passengers's life safety in subway fire. As a result of evacuation simulation without fire, evacuation times are 36 s for EXODUS V4 and simple hand calculation, and when fire is occurred fire, 101 persons evacuated in 32 s. Therefore, a countermeasure of evacuation in subway carriage fire is required to repression of fire and emergency exit.

• 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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• 2007.05a
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• pp.418-429
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• 2007

This study aims to investigate the relationship between spatial layout and space use pattern in subway station. Details investigation is carried out using space syntax method and observation of people's movement in Kangnam subway station. Space syntax method describes spatial layout quantitatively. The study reveals that space use pattern can be predicted by spatial layout of subway station using space syntax method. This study suggests that by applying space syntax method in planning stage we can design subway station objectively considering passenger's movement.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.581-584
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• 2007

The subway concrete box structure can`t establish expansion joint because of animal power delivery of the subway rail. In this case, As increase of structure volume, it is subjected to cause temperature crack. The temperature crack due to the heat of hydration classified a nonstructural crack. but it has a bad effect on durability of concrete structures. especially, in case of a subway concrete box structure, when a water-proof facilities is beaked on an outer-wall, the water leakage occurs through a penetration crack generated from a wall of the concrete structure too. This paper, for the subway concrete box structure, examined a condition of temperature crack occurrence by a heat of hydration concerned external temperature from analysing by a three dimensional finite element method.