• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.3
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• pp.521-528
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• 2022

The beginning of a new railroad history is progressing every year. Seoul's Sillim Line is a new transportation system based on communication technology. Sillim Line is the nation's first wireless communication-based unmanned train control system based on KTCS-M, the national standard. The use of wireless communication technology in the rail transportation system suggests the possibility of exporting to the global rail market. This is the result of the government's development and implementation of various support policies for nurturing the domestic railway industry and for export. In this paper, the status of support for localization of railroad industry technology implemented by the state is reviewed, and the process by which railroad parts are replaced by localized parts is analyzed out of dependence on foreign countries. A study was conducted on the development of a technical support platform to solve the technical difficulties of the industry that occurred in this process.

• The Journal of the Convergence on Culture Technology
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• v.8 no.4
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• pp.407-413
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• 2022

In this study, the empirical formula for evaluating cable tension based on long-term measurement for about 3 years according to temperature change was proposed by proving the correlation between the expansion joint displacement of the upper road bridge and the cable tension of the lower railway bridge. The tension prediction results using the empirical formula for tension evaluation each cables proposed in this study were found to be in good agreement with the cable tension using the vibration method within 3%. Therefore, it was analyzed that it could be applied together with the vibration method that was an experimental technique, to predict and evaluate the cable tension in serviced railway steel composite bridge. As a result of applying the estimated temperature calculated by the empirical formula for expansion proposed in this study to the empirical formula, it was analyzed that a high level of reliability could be secured when compared with the vibration method. Therefore, it is judged that the empirical formula for cable tension evaluation reflecting the estimated temperature proposed in this study can be used to predict the tension of cables according to climate change in the future and establish a maintenance plan.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.599-607
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• 2021

Street-view images, which are omnidirectional scenes centered on a specific location on the road, can provide various obstacle information for the pedestrians. Pedestrian network data for the navigation services should reflect the up-to-date obstacle information to ensure the mobility of pedestrians, including people with disabilities. In this study, the object detection model was trained for the bollard as a major obstacle in Seoul using street-view images and a deep learning algorithm. Also, a process for updating information about the presence and number of bollards as obstacle properties for the crosswalk node through spatial matching between the detected bollards and the pedestrian nodes was proposed. The missing crosswalk information can also be updated concurrently by the proposed process. The proposed approach is appropriate for crowdsourcing data as the model trained using the street-view images can be applied to photos taken with a smartphone while walking. Through additional training with various obstacles captured in the street-view images, it is expected to enable efficient information update about obstacles on the road.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.6
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• pp.715-725
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• 2021

When constructing railway stations, gates shall be located in appropriate locations for convenient use. However, to reduce construction costs, the number of gates was minimized and the location was not appropriately placed to the direction of many users. This study proposed a method to calculate the benefits of additional gate installations using the improvement of pedestrian traffic flow, occupied area and travel time as economic effects. In particular, a method of estimating the percentage of people using certain gates and the number of people by route within the station was proposed. This method was applied to analyze the effect of additional gates to Gwang-myeong Station on the Shinansan Line, which is to be opened in 2025. The effect has only improved in mobility. The first year of its opening was estimated at 5.91 billion won for mobility and 75.8 billion won for cost, and the B/C was 1.21 for 30 years after its opening. It is expected that this method will be applied to systematic effect analysis when additional gates are installed at unopened railway stations as well as existing railway stations.

• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.265-270
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• 2022

The purpose of this study is to derive the damage weak part of the elastic rail fastening system for concrete tracks (System 300-1). In the concrete tracks, the elastic rail fastening system sticks the rail and the sleeper and reacts all the time when the train is running. Among the components of the rail fastening system, the resilience pad and tension clamp were fatigue members and were constantly deformed in response to compressive and uplift forces. In this study, the residual deformation characteristics of the tension clamp according to the period of use were analyzed using by specimens taken on site in the same section for 6, 11, and 16 years on the serviced urban transit. In addition, the damage mechanisms for each component were derived based on finite element analysis. As a result of the numerical analysis, the stress (strain) of each part of the tension clamp according to the external force from the applied clamping force was analyzed to derive the damaged weak part of the tension clamp.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.727-732
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• 2022

Applying the calculated cross-sectional reduction due to the corroded rebar investigated in the field to the numerical analysis model, the damage pattern and delamination of concrete in the field showed a tendency relatively similar to the numerical analysis results. It was analyzed that when the expansion pressure due to corrosion of the reinforcing bar is greater than the tensile stress of the concrete, cracks are generated and the concrete cover can be fracture. As a result of this study, the correlation between the corrosion rate of reinforcing bars and the crack occurrence of the concrete cover of the subway box structure was verified based on the numerical analysis and field test results. To prevent rebar corrosion, the corrosion rate can be reduced by applying rust prevention to the reinforcing bar and changing the material. In the case of exposed to a corrosive environment, the tensile strength of the concrete is improved by adjusting the concrete compressive strength to secure durability against the expansion pressure caused by the corroded rebar.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.547-552
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• 2022

In this study, shape-based track management by analyzing track irregularity was studied in terms of force-based track irregularity analysis by numerical analysis of wheel-rail interaction force using by the measured vertical irregularity. The effect of the vertical irregularity of the track due to the difference in track types on the wheel-rail interaction force and the track acceleration in the connecting section of the sleeper floating track and the direct fixation track on concrete bed were analyzed. As the results of this study, the measured vertical irregularity was directly affect the vertical wheel load (the wheel-rail interaction force) and the rail acceleration, and it has been demonstrated to change consistently. In this study, the adequacy and necessity of the force-based track irregularity analysis method was verified based on the wheel-rail interaction analysis using the the measured vertical irregularity.

• The Korean Journal of Emergency Medical Services
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• v.27 no.2
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• pp.7-17
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• 2023

Purpose: This study aimed to identify the factors that contribute to head injuries among drivers of personal mobility devices and provide insights into safety perceptions. Methods: This retrospective study analyzed data of 221 trauma patients obtained from electronic medical records and the National Emergency Department Information System (NEDIS) over one year, from August 1, 2021, to July 31, 2022. The patients, all in their 20s and 30s, presented to a single emergency medical center following personal mobility device accidents (motorcycles, electric scooters, and bicycles). Results: Among motorcycle riders, 18.2% were not wearing helmets, while the percentage of e-scooter riders not wearing helmets was 87.5%. Wearing a helmet was associated with a 71.2% lower likelihood of head injuries (OR=0.288, CI=0.163 to 0.509, p=0.000). Of the personal mobility devices, motorcycles had a 0.431 times lower odds ratio for head injury compared to e-scooters (p=0.009), and there was no significant difference between e-scooters and bicycles (p=0.776). Conclusion: It is imperative to strengthen safety regulations by mandating helmet use for riders of personal mobility devices. A system to enhance driving enforcement for electric scooters, which are increasingly popular among young adults, should also be established.

• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.277-282
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• 2022

The sleeper floating track (STEDEF) in this study was a track type in which a very soft resilience pad was installed under a relatively thin concrete sleeper (RC Block). Therefore it was expected that the resilience pad could affect the estimation results of the concrete strength. In this study, field applicability evaluation was performed to apply the rebound hardness test method, which was a general method for estimating the compressive strength of concrete in civil structures, to concrete sleepers of railway tracks. In order to analyze the strength estimation technique of concrete sleepers reflecting the characteristics of track structures different from those of civil structures, the parameter experiments that could affect the strength estimation results of concrete sleepers in a serviced line were performed. As a result of the study, the appropriate hitting position was suggested considering the shape of the concrete sleeper, and the difference in strength estimation results according to the condition of the concrete sleeper and supporting conditions was derived.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4D
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• pp.539-543
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• 2008

The Directional sign system in Korean high speed railway stations has a lot of problems. For an example, It lacks of consistency in the shape or allocation. Also, the signs do not match with the actual directions sometimes. Last but not least, the view is blocked by the other signs such as advertisement or other barriers. We suggested the methods to standardize the sign systems that include visibility, accuracy, consistency, and simplicity. First, we categorized signs into directional signs, locational signs, and infomational signs. Then, we examined the actual high speed railway stations in Korea to learn the real situation. Finally, we suggested the methods to standardize the sign systems considering the factors that are visibility, accuracy, consistency, and simplicity.