• 한국전산유체공학회:학술대회논문집
• /
• 2010.05a
• /
• pp.208-213
• /
• 2010

In this study CFD(Computational Fluid Dynamics) analysis of the steady fire-driven fuid flow for the performance test of ventilation at railway tunnel between Heuksok and Nodeul Station from Seoul Metro 9 is performed. There were fans with exhaust and intake modes and each was installed at the middle and both ends of the tunnel. For this test, the pool fire source of methyl alcohol with 1.5MW and smoke generators were installed between the middle of tunnel and Heuksok Station. In this test, the smoke behavior from natural convection was observed for 10 minutes from the ignition of pool fire and then fans with intake-modes at both sides of Heuksok effect of fan-on with intake mode located in the opposite side of the tunnel nearby Heuksok Station on fire-driven fluid flow is studied on when the boundary conditions of fan-on at the tunnel between Heuksok and Nodeul Station are the same as test. FLUENT, a commercial CFD code, is used for this analysis.

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.315-323
• /
• 2010

It is suggested that the service life of the continuous welded rail(CWR) is estimated by the relationship between the rail surface irregularity according to the accumulated passing tonnage and bending fatigue of welded part in CWR. In this study, it measured bending stress of rail according to the rail surface irregularity in the concrete track on the Seoul Metro. In addition, the relationship between rail surface irregularity and bending stress in concrete track is analyzed by results of the field test. Finally, this study clarified the relationship among bending stress(Y) of rail, train speed(U), rail surface irregularity(v, w) in concrete track. The result of this study is able to use the basis data to establishing the periodic replacements criterion of CWR.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.1408-1415
• /
• 2007

To operate Platform Screen Door (PSD) automatically, the operational data of PSD and the train must be interfaced properly. PSD and train are operated together by the signaling system in Automatic Train Operation (ATO) signaling system zone where interfaces are provided between PSD and train. However, the additional PSD interface system with train is required in train operating zone without the interface between PSD and train. For the PSD interface, the wireless communication system or the train status (train correct stop status / train door status) detection system has been used. Seoul Metro line No.2. has the PSD wireless communication system using 447MHz band RF. For the safety of PSD operation, it is required to prevent RF interference in the subway environment where many frequencies exist. In this paper, the PSD wireless communication system is developed using 2.4GHz band RF to prevent the interference of the wireless communication and increase the traffic of the PSD interface. Furthermore, the improved system can store, manage and display the PSD and train operational data using Human Machine Interface (HMI) in the train's driver cab.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.1058-1070
• /
• 2007

Internal and external railway management corporations are using the periodic replacement criteria of rail by accumulated passing tonnage and wear to maintain rails for servicing. However, internal the periodic replacement criteria of continuous welded rail(CWR) by accumulated passing tonnage is the one(50kg/m-5 million gross tonnage, 60kg/m-6 million gross tonnage) presented in Japan before. It was estimated with the fatigue life about 50kg N rail joints applied diesel train load but it wasn't applied to current conditions of track; elimination of rail joint, using the concrete slab track and operation of light train load and effect of welding, manufacturing technique, grinding of rail. Therefore, in this study, it was investigated the types of damage and cause in welded rails and examined standards and information resources. Also, this study presents preliminary data to revise the periodic replacement criteria of CWR by current accumulated passing tonnage in bending test of laid welded rail and a survey of track maintenance history of Seoul metro.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.7
• /
• pp.1019-1025
• /
• 2015

The performance requirements on the safety-based functionality of railway signal systems have been reinforced and the effort for enhancement of the existing system or development of the new system is being accordingly made. In particular, various technical researches on replacement or improvement of the existing ATS(Automatic Train Stop) signaling system are now in progress for better operational efficiency. In this study, the complementary points for improvement or replacement of the currently used system(i.e., ATS) will be derived in terms of operating efficiency in an integrated operating environment with the newly introduced system(e.g., ATC: Automatic Train Control). This study can contribute to derive the need for improvement of the signaling system by checking the interface problems and comparing between different systems through the analysis of real operation cases in the field. Eventually, this analysis can be applied to prevent and estimate the collision accidents can be caused by the failure of the signaling system in advance. In addition, the results can be used to provide a future direction to secure the reliability in the parallel operation by integration based on different railway signaling systems.

• Journal of Labour Economics
• /
• v.31 no.3
• /
• pp.1-19
• /
• 2008

This is an empirical study in Korea on the effects of the minimum wage. Based on the survey data of security workers of 132 apartment in Seoul metro area, the study finds that the introduction of minimum wage in this sector in 2007 raised wage by 10.9%, reduced employment and work hours by 3.5-4.1% and 13.5% respectively. This implies a short run wage elasticity of employment of -0.312 but much higher elasticity of work hours of -1.68.

• Journal of the Korea Concrete Institute
• /
• v.21 no.5
• /
• pp.649-660
• /
• 2009

A nonlinear column model of an internally confined hollow (ICH) reinforced concrete (RC) column was suggested and a parametric study was performed. The suggested column model considered the confining effect and the material nonlinearity of concrete. To verify the suggested column model, its analysis results were compared with the test results from previous researchers and a quasi static test performed in this study. They showed that the suggested column model was reasonable and had acceptable accuracy. The results from parametric studies showed that the thickness of the internal tube, concrete strength, and the hollow ratio of the ICH RC column affected its behavior.

• Fire Science and Engineering
• /
• v.20 no.2 s.62
• /
• pp.21-30
• /
• 2006

Since Daegu subway arson fire disaster in 2003, there have been several copycat crimes such as at Seoul Metro line number seven and Hongkong Chuiwan line cases. Oil and gas were used for fire propagation in most cases as in Daegu case and such fire could be expanded to a whole subway cabin within several minutes. The fire may eventually cause the whole subway system stop. Fire damage can be minimized when fire occurrence and diffusion are blocked by stages or isolated rapidly. This study suggests an effective early response system that separates passengers from fire and a real-time fire extinguishment program by stages. Based on the subway arson case studies, the early response scenario has been structured by three stages, i.e., confirmation of fire and damage, early fire extinguishment, and information dissemination and passengers evacuation.

• Journal of the Korean Home Economics Association
• /
• v.30 no.2
• /
• pp.113-137
• /
• 1992

The purpose of this study was to figure out the urban establishing families' economic structures(income, expenditure, assets, first-present-future housing cost etc.), the states of first-present housing, the future housing plans, and the housing preferences. For this purpose 274 establishing families in Seoul and its metro-politan area were interviewed through the standardized questionnares. Finally 264 questionnares were analyzed. The major findings were as follows; 1. The important source of their monthly incomes was the labor income. But there was often the transfer income from their parents. And the important items of monthly expenditures were savings and foods. In higher income classes, the traffic cost was important relatively. 2. It was found that the urban establishing families were very dependent on their parents for their first-present housing costs. The dependency was stronger in high education classes compared to the low. This was the case in future housing costs. 3. The states and changes of first-present housing showed the demands for an apartment, homeowership, and privacy. These tendencies were higher in high education classes compared to low education classes, but the demands for future housing were according to the monthly income. The present locations were determined majorly by the distance from office and parents. 4. Their housing preferences were different from the present housing states. Furnished rental housing, open living space, large common spaces, and common using of unusual appliances etc. were more preferred by high education classes compared to low education classes.

• Journal of the Korean Society for Railway
• /
• v.17 no.2
• /
• pp.148-155
• /
• 2014

This practical study investigates the effects of job satisfaction as a result of the stresses felt by many dispatchers who work in the subway industry in the Seoul metropolitan area. Factors that cause stress are assessed. The organization system, inappropriate compensation, workplace culture, and job requirements, among several types of organizational stresses are significantly related to job satisfaction. The results of the analysis indicate that there is a close link between job satisfaction and dispatcher communication factors. This paper suggests stress-relief measures for dispatchers who must handle a variety of civil complaints and improper communications with field departments based on the analysis of the answers to descriptive questionnaire items.