• Journal of the Korean Operations Research and Management Science Society
• /
• v.34 no.3
• /
• pp.105-124
• /
• 2009

Data Envelopment Analysis (DEA) is a methodology of computing the relative efficiency of each decision making unit (DMU) by comparing it with other DMUs having similar input and output structure. In this paper, we compare the efficiency of Korean rail transit corporations using DEA. To do this, we design a DEA-AR/AHP model, and evaluate efficiency by comparing the subway operating agencies of six big cities. The analysis reveals that Seoul Metro and Seoul city railroad construction turn out to be the most efficient groups. The result of this research can provide helpful information for effective management in a domestic subway operating agency.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.1
• /
• pp.100-105
• /
• 2007

Signalling equipments at railroad sites are widely exposed to high voltage lightning surges. This paper presents a lightning protection system for the signalling equipments at subway car depots. The main features of the system are as follows : (1)the common grounding system between power system grounds and the signaling system grounds, (2)physical and chemical methods to reduce grounding resistivity, (3)rearrangement of lightning rods based on the rolling bal1 theory, (4)equi-potential bonding networks to minimize the potential differences between the equipments grounds. The system has been constructed at six subway car depots in Seoul metropolitan area and it is measured that the grounding resistivity are reduced to 0.266 ohms and the potential differences between devices are reduced to a negligible quantity. After the construction of the systems, it has not been reported the break-down of the signalling equipments caused by lighting surges.

• 한국터널공학회:학술대회논문집
• /
• 2005.04a
• /
• pp.292-298
• /
• 2005

Tunnel in subway should be designed as a water-proof type tunnel as much as possible but it is difficult to make it come true due to several facts, such as construction technique and cost. A drainage type tunnel as a substitute of a water-proof tunnel lead to the increase of water pressure on the concrete lining that make bad effect to tunnel structure when it has some problem to operate the drainage system. Throughout studying about cases on defects of tunnel drainage in subway We hope it contributes to tunnel maintenance.

• Explosives and Blasting
• /
• v.14 no.2
• /
• pp.63-70
• /
• 1996

This paper describes the method used to determine the optimal section for the horseshoe shaped single tunnel which is utitized widely in constructing subway tunnels. Vehicle and structural gauges conform to the design criteria for the Seoul Subway Line 5. The tunnel sections are determined considering the structural stability, and the tunnel excavation area is optimized so as to minimize design and construction costs.

• Proceedings of the KSR Conference
• /
• 2008.06a
• /
• pp.470-480
• /
• 2008

After 1th line was built in 1974, the history of subway in Korea has been expended to 9th line which is under construction. It is time to prepare nation wide subway grounding system urgently according to the domestic electric standard that aligns to world wide standard by WTO/TBT treat (1995). Newly added grounding system to the fundamentally different system caused many problems. PSD(platform screen door) and other newly added equipment are also need grounding system. By the electrical code(established by Korea Electric Association), low voltage equipment(including grounding system) under 1,000V AC are in the process of change into IEC 60374. IEC 60364 standard will be added to the electrical code(established by Korea Electric Association) in 2007 and amended and after 3-5 years later, it will become a complete IEC 60364. So the purpose of this study is to compare the domestic rail road grounding system and suggest the standardized grounding system for the newly built subway.

• Proceedings of the KSR Conference
• /
• 2004.10a
• /
• pp.168-173
• /
• 2004

This research shows the method about the auto extinguishing system construction for the subway train's safety operation. The safety system is the total auto extinguishing system which it is able to overcome the emergency situation, to see fast using the sensing system, to interface using the communication system, finally to extinguish the large-scale fire happened. The system model is the total disaster mitigation system model preventing the arson or terror. and to apply a method of the fire extinguishing system using reinforced fire extinguishing agency in the world first. It is to use the subway train and the railroad train which is prevented and mitigated the large-scale demage the same as the arson and the terror.

• Proceedings of the KSR Conference
• /
• 2003.10c
• /
• pp.523-528
• /
• 2003

AS City traffic means, the electric railway of the role is overwhelming with recognizing good merits of safety, no environment disruption and accurate destination time. Currently, Korea subway are running about 290km through eight subway lines. The latest constructed subway had been made by imperoved matherials which is going on improving. Therefore, we researched this project to keep up facilites easily, repress a leakge current and reduse install cost and repair time in changing facility at overhead Contact wire system because of arc by reforming construction plan about Expansion Joint and Air Section which is regarded as weak point when facilities are fixed and maintianed of Rigid Trolley bar System. as above we can contribute various part to making useful O.C.S(overhead contact wire system)

• Journal of the Korea Safety Management & Science
• /
• v.13 no.3
• /
• pp.19-28
• /
• 2011

The efforts to reduce industrial accident has been brisk recently in workplace. These efforts were mainly concentrated on construction and manufacturing. Despite these efforts, current accident rate so far has been maintained on the fixed level. According to the change of industrial structure, the government's attention on industrial accident prevention activities are focused in service industries. When trying to appraise the result of such activities, it is impossible to evaluate safety without certain criteria. Therefore, we analyze data by TOPSIS method that all the subway institution jointly manage every year. we decide the order of safety priority between domestic subway workplaces and measure the variation in safety by sensitivity. As a result, we draw conclusions to improve safety for the primary consideration and suggest alternatives.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.3 no.3
• /
• pp.187-194
• /
• 1999

In this study, a series of items on the safety and stability of cracked main structure in subway are investigated and analyzed. Cracks due to dry contraction under the construction can be found when a tensile stress of cross section is higher than tensile strength at a value of coefficient of dry contraction $200{\times}10^{-6}$. It is concluded that there is no problems when load carrying capacity, that is, an ability of resisting loads of structure is enough in this analytical model. Also, it is concluded that this model has a desirable serviceability because a width of bending crack is lower than allowable one.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.1953-1959
• /
• 2011

Subway stations have a characteristic that the facilities in the ceiling should be checked, replaced and expanded frequently. The new installation of supports (steel anchors) for new facilities and workers moving-around in the ceiling result in the damage in the ceiling finish material and concrete structure which also result in construction cost increase. In addition, the noise, vibration and dust generated during the work harm the station environment. There are civil complaints on these which give difficulty to ceiling works. Accordingly, this study suggests a ceiling frame construction method that considers the convenience, economy and efficiency of ceiling work by improving the support installation method for facilities in ceiling.