• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.6
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• pp.607-613
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• 2008

A monitoring system for the subway structures using prestrained FBG sensors fixed with partially stripped fibers was developed. The sensor packages had pre-strain controllable fixtures. Tensile and compressive strain of the structure could be measured without slip. The FBG sensor system was applied to the concrete lining structure in Taegu subway. Near the structure, the narrow tunnel construction, for the electric power cables and telecommunication cables, started. We wanted to measure the deformations of the subway structures due to the construction by the FBG sensor. The applied sensors had the gauge length of 1 meter to overcome the inhomogeneity of the concrete material with enough length. In order to fix tightly to the structure, the partially stripped parts of the sensor glued to the package and slip phenomenon between fiber and acrylate jacket was prevented. Prestrain of the sensor was imposed by controlling the two fixed points with bolts and nuts in order to measure compressive strain as well as tensile strain. The behavior of subway lining structure could be monitored very well.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.04a
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• pp.114-121
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• 1995

Problems of noise and vibration induced by subway operation became one of the major factor when new subway 1 me is under consideration. One of the most economic method in reducing the noise and vibration is the increasement of the tunnel mass. . Vibration of the massive tunnel structure has been measured induced by subway operation. STEDEF system which was adopted by Seoul Metropolitan Subway Bureau has been proved that more than 99% of the vibration has been decreased at the bottom of the railway track. Most of the vibration measured inside and outside of the tunnel showed that their peak frequency is around SOHz or 100Hz. The propagation characteristics of vibration in massive tunnel , wave propagate in three directions. Overall frequency in the range of 0 to 125H2 horizontal transmission usually increase, while vertical transmission decreases about 50% in the range of 0 to 25Hz and 90Hz to 125Hz regardless of modal shape.

• 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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.2
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• pp.103-111
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• 2006

To optimize the ventilation and smoke control systems in subway equipped with platform screen door, the technology to analyze the unsteady tunnel flow caused by running of train should be developed. The development of model experiment and numerical analysis technique with relation to unsteady flow of subway were presented. The pressure and air velocity changes in 1/20-scaling experiment unit were measured and results were comparied to those of 3-D unsteady numerical analysis applied with sharp interface method. The experimental and numerical results were quantitatively similar and it would be reasonable to apply sharp interface method to analyze the unsteady flow in subway equipped with platform screen door.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.184-190
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• 2009

Recently, the concern for the reliability of railway is increasing, also the study about reliability is being processed at a good pace. However, in case of an existing railway operating it is true that the railway system is being operated without a clear RAM standard. There is not a clear RAM standard about product menual of a city railroad, and there are only basic provisions concerning traction motor which can be called a main equipment. In this paper, we calculated the availability and reliability of subway having MKBSF, MKBF, MTBF, MTTR analyzing accumulated maintenance data about a main equipment of a VVVF direct subway being operated in line #4. By watching the reliability grade of a VVVF subway being operated and manufactured within the country and being applied with the development of a city railway reflected by RAM menual when the new subway is manufactured, and with the basic data of RCM, we'd like to grope the methods which can be improved by operation stability of a city railway.

• Journal of Industrial Technology
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• v.23 no.A
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• pp.93-100
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• 2003

Population concentration phenomenon of city needs large-scale ride, and It is important elements that develop the circumference but, it is difficult to evaluate effects that ride gets land utilization change. Therefore, this research evaluates change and effect of land utilization as political to subway station that is main ride of Seoul City, and chose standard and position for right place arrangement of electric railway station. Research contents analyzed subway station effect area interior and external land utilization change taking advantage of GIS's buffer function and RS's classification technique, and decide precedence at subway station establishment and chose position of subway station for effect area outside area.