• Proceedings of the KSR Conference
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• 2007.11a
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• pp.965-968
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• 2007

Two major parameters, i.e. carbon dioxide ($CO_2$) and particulate matters smaller than $10{\mu}m\;(PM_{10})$, were selected as the index pollutants in managing indoor air quality. The former pollutant, $CO_2$, is the index that shows the ventilation status and is exhaled by passengers when they breathe in train or subway. It is generally known that high $CO_2$ concentration in the vehicle may be decreased by insufficient air-tightening vehicle bodies and the air is ventilated when vehicles stop at the station and doors open. However, there is no established proof or quantitatively identified data on how much the $CO_2$ concentration is reduced when ventilation is done while doors are opened. In this study, $CO_2$ concentrations were measured in 6 lines of Korail and one line of Seoul Metro subway linesand a theoretical approach was takento predict the changing trend of $CO_2$ concentrations during the operation of vehicle by using $CO_2$ dilution factor through natural ventilation. As a result, the change could be quantified and it was found that app. 35% of indoor $CO_2$ was removed through natural ventilation.

• Journal of Welding and Joining
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• v.30 no.5
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• pp.40-45
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• 2012

Nowadays in Republic of Korea, whole amount of the thermite welding powder for rail joinning is dependent on import. However the demand of the thermite welding powder would be enlarge because some constructing high-speed train and city metro projects are currently in progress. In addition this is the main reason why we should develop the thermite welding powder, domestically. This study is focused on utilizing the recyclable materials like Al powders from cans and iron oxide scales from wire rods as the main components of the thermite welding powder. By minimizing Al content in weld zone by controlling the mixing ratio of the Al powder in the thermite welding powder, the excessive dissolution of the Si and Mn components came from the Al powders could be controled. The tensile strength of welding zone in welded rail was 740 MPa, with that the developed thermite welding powder.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2163-2172
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• 2008

The noise to be considered as the most important in railway systems is the noise generated from the wheel/rail interaction. Such noise can be divided into three categories; that is, the rolling noise, the squeal noise and the wheel howling noise. Especially in metro systems, this type of noise has been considered seriously in recent years, and the diversified studies on the mechanism and solutions of such noise are in progress by many railways and researching bodies. In this study, a specially designed wheel absorber is installed in the wheel, and FEM analysis and laboratory tests are executed for the two cases, i.e. with wheel absorber and without wheel absorber, to check the effect of the wheel absorber in noise reduction. For the FEM analysis, the frequency response functions for respective cases are compared. And, for the laboratory test, following four cases are tested and compared; that is, i) with wheel only, ii) installation of ring damper only, iii) installation of damping material and cover, iv) installation of complete absorber system.

• Journal of the Korean Society for Railway
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• v.14 no.4
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• pp.348-353
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• 2011

Iron fillings which were accumulated around the rail was often the cause of abnormal signal in case of signaling equipment using rail as transmission line. Iron fillings were generated on curved section of railroad due to the friction between rail and wheel, and metro line company urged to find the way to remove these iron fillings, because these were often the cause of abnormal signal. Magnetic device for trapping iron fillings around concrete slab tracks is introduced. The characteristics of magnetic device were analyzed using basic design and numerical analysis method. Magnetic device for trapping iron fillings were examined for application to the train which were operating in commercial line.

• Journal of the Korean Society for Railway
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• v.15 no.4
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• pp.364-369
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• 2012

This paper presents an experimental study on the radio propagation characteristics in subway tunnel at 18GHz frequency band which has been assigned to video transmission between train and wayside. The radio propagation tests are carried out in the subway tunnel of Seoul Metro using the antenna and communication devices of the prototype video transmission system. The measurement results show that 18GHz radio propagation in subway tunnel has smaller path loss than that of general outdoor radio environment. It is also cleared that the arch-type tunnels have smaller radio propagation losses than rectangular tunnels, and single track tunnels have smaller pass loss than double track tunnels. From the measurements, the radio propagation coverage is worked out as 520 meters. The curved tunnels which cannot have LOS communication between transmitter and receiver have large pass losses and fluctuation profile along distance. The radio propagation coverage along curved tunnels is worked out as 300 meters. These investigation results can be used to design the 18GHz radio transmission system for subway tunnel by providing the optimized wayside transmitter locations and handover algorithm customized to the radio propagation characteristics in subway tunnels.

• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.379-385
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• 2019

The purpose of this study is to investigate the damage status of wood sleepers on concrete track of urban transit at different locations and to analyze the causes of damages. In addition, the turnout maintenance history during the service period of about 24 years was analyzed in conjunction with the train passing tonnage and that was to compare the current repair history. The most frequent damage components were rail, tie plate, spike and wooden sleeper. And, the damage caused by the defect of the rail fastening system such as spike and tie plate according to the deformation of the wooden sleeper was analyzed as the main type of damage. As a result, the damage of track components of turnout system was on the increase because they are directly affected by the train passing tonnage. The supplementary points of the check sheet for current turnout maintenance were derived and the improvement proposal was suggested based on the research results.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.3
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• pp.353-362
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• 2015

Platform screen door (PSD) installed at underground subway station has reduced the safety accident, but it may cause poor air ventilation condition due to the isolated exhaust duct in the subway tunnel area. In this study, the additional ventilation system was suggested, which can be installed at a void space (i.e., storage room under stairs) of platform in order to improve efficiency of air ventilation rate. Exhausted air from platform was directed to underneath of platform and joined with existing ventilation duct of train exhaust system (TES). One subway station in Seoul city was selected to predict the effectiveness of the suggested lower exhaust system by using the computational fluid dynamics (CFD) analysis. The predicted mean age of air was decreased by 16.5% which proves the improvement of air ventilation efficiency when the suggested lower exhaust system was applied.

• Science of Emotion and Sensibility
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• v.19 no.4
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• pp.33-40
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• 2016

The purpose of this study is to improve social protection and benefits for pregnant women with the usage of LED care emblem. The study was conducted in the Seoul Metro by two research assistants on January 20th to 30th, 2015. One of subjects wore the LED care emblem and the other was present to record the data. An experiment was carried out total 60 times by wearing LED care emblem in 2 positions ((a) necklace and (b) bag), and 3 usages of Light ((1) Constant light, (2) No light which is like existing care emblem, and (3) blinking light at one-second intervals). Experimental results show there was a significant difference depending on the type of light. Mostly seat offering was the type of light (1) Constant light and it has 8 times (13.4%). The type of light (3) blinking light at one-second intervals has only 2 times (3.4%) seat offering. However, there were no seat offerings at the type of light (2) No light. Meanwhile, there were no significant differences in wearing position, time, the number of people in the train and gender. This study suggests that it is necessary to make LED care emblem with constant light in order to induce spontaneous seat offering.

• Journal of the Korean Society for Railway
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• v.15 no.4
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• pp.402-407
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• 2012

Since reports on trip delays or incidents often appear as accident articles on the press, the social criticisms and concerns on the safety of the urban railway are increasing. Therefore, a railway authority sometimes adopts an abstract safety goal like "let's build the urban railway to a masterpiece level" or "let's obtain an aeronautic safety level" to make citizens relieved and to alert involved persons. However with a vague goal, it is almost impossible to make an implementation plan systematic which helps the authority academically verify and validate if the goal is achieved or not. In this paper, the features of the railway safety are described and the safety models for securing the safety of the urban railway are surveyed and categorized. Based on the comparisons among the features and limitations of the models, we identify a more practical model which can be applied to the urban railway more effectively.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.3
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• pp.27-39
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• 2009

The 1st Incheon Rapid Transit Line opened in October, 1999. However, the current development plans for areas near stations do not involve plans for the both urban planning and transportation together. As the focus on only the aspect of installing a new transportation mode, the developments even make the problems such as reckless development and traffic congestion gets worse. It is required to analyse status of the current land uses and land use plans in the future and consider distribution of functions of the areas near stations and aims of development plans so as to harmonize the functions of each region in view of making balance in the whole city. The aims of developments of areas near stations has to focus on the study follows steps to find and suggest aims and strategies for the revitalization plan for areas near stations with considering the both transportation and land uses together. The plans for the areas near stations of the Incheon 1st Rapid Transit Line are analysed and then the features and rational strategies are derived. The impact is analysed as applying the development strategies derived from the step into the areas near the stations of Incheon 1st Rapid Transit line.