• Proceedings of the KSR Conference
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• 2005.05a
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• pp.151-156
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• 2005

The objective of this study is to devise an accident scenario analysis method adept at creating accident scenarios at the Preliminary Hazard Analysis(PHA) step of a hazard analysis for railway system. This approach was inspired by the Quality Function Deployment(QFD) method, which is conventionally used in quality management and was used at the systematic accident scenario analysis(SASA) for the design of safer products. In this study, the QFD provides a formal and systematic schema to devise accident scenarios while maintaining objective. The accident scenario analysis method first identifies the hazard factors that cause railway accidents and explains the situation characteristics surrounding the accident. This method includes a feasibility test, a clustering process and a pattering process for a clearer understanding of the accident situation. Since this method enables an accident scenario analysis method to be performed systematically as well as objectively, this method is useful in building better accident prevention strategies. Therefore, this study can serve to reduce railway accident and be an effective tool for a hazard analysis.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.599-604
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• 2005

As a public transportation possible to convey a large quantity, the railway is safe and keeps time, but it has hazards to cause a disaster if the accidents such as collision, derailment, and fire occur. So advanced countries carry out System Safety Plan with various program activities which have connected orders to maintain or improve safety level by finding hazards, evaluation, taking measures and practice, and improving problems. Especially they systematically manage hazards to cause railway accidents and the factors which possibly threat safety, using national classification of risk and causes with analysis of the related data such as establishing accident/incident data and safety regulations/standards. As executing railway safety regulations, domestic railway is currently trying to improve railway safety management system. The research of classification system of accidents/incidents is one thing to make railway safety management systems better. In this research, we reviewed hazardous factors of railway systems and classification of the causes as the beginning of system safety management, and we conducted study on development of railway accident classification based on findings of this research. The results are able to be used in identifying hazards and activities of systemic safety management at the step of railway accident report and investigation.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.07a
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• pp.69-71
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• 2023

본 논문은 YOLO 기반 모델의 철도 시스템 내 선로 고정장치 탐지 성능을 비교하고 분석한다. 여기서 철도 시스템은 열차가 주행하기 위한 선로, 침목, 패스너 등의 구성요소를 포함한다. 침목은 지반과 직접적으로 연결되며, 선로를 지반 위에 안정적으로 지지하고 궤간을 정확하게 유지하는 역할을 한다. 또한, 패스너는 선로를 침목에 단단히 고정시키는 역할을 한다. 이러한 선로 고정장치의 부재는 인명 사고로 이어질 수 있어 지속적인 관리와 유지 보수가 필수적이다. 본 논문에서는 철도 시스템의 선로 고정장치 탐지를 위해 YOLO V5 및 V8 딥러닝 모델의 적용 가능성을 실험적으로 접근하며, 두 모델의 탐지 성능을 비교한다. 실험 결과, YOLO V8 및 V5 모델은 모두 뛰어난 성능을 보이는데, 특히 YOLO V8 모델이 더욱 우수한 성능을 보인다. 이로써 YOLO 알고리즘은 선로 고정장치 탐지에 적합하다는 것을 증명한다. 그러나 일부 False Positive Sample이 관측되었음을 확인하고, 이로부터 모델 성능의 개선이 필요하다는 결론을 도출하였다.

• Journal of Advanced Navigation Technology
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• v.25 no.3
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• pp.256-266
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• 2021

Domestic and foreign studies point to human factors as the main cause of unmanned aerial vehicle accidents, and HFACS is introduced as a technique to effectively analyze these human factors. Until now, domestic and foreign cases of analyzing the human factors of unmanned aerial vehicle accidents using HFACS were mainly targeted by military unmanned aerial vehicles, which can be used as an objective cause identification and similar accident prevention tool. In particular, identifying the focus of HFACS application considering the performance and operation conditions of domestic civilian unmanned aerial vehicles is expected to greatly help identify the cause and prevent recurrence in the event of an accident. Based on HFACS version 7.0, this study analyzed the accident investigation report data conducted by Korea Aviation and Railway Accident Investigation Board to identify the focus of HFACS application that can be used for domestic civilian unmanned aircraft accident investigations.

• Journal of the Korean Society for Railway
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• v.13 no.2
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• pp.139-146
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• 2010

In this study, a new equivalent modeling technique of rollingstock for 1-D collision dynamics was proposed using crash analysis of 3-D finite element model in some detail. To obtain good simulation results of 1-D dynamic model, the force-deformation curves of crushable structures should be well modelled with crash analysis of 3-D finite element model. Up to now, the force-deformation curves of the crushable structures have been extracted from crash analyses of sectionally partitioned parts of the carbody, and integrated into 1-D dynamic model. However, the results of the 1-D model were not satisfactory in terms of crash accelerations. To improve this problem, the force-deformation curves of the crushable structures were extracted from collision analysis of a simplified train consist in this study. A comparative study applying the suggested technique shows in good agreements in simulation results between two models for KHST.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.3
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• pp.287-298
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• 2007

Recently, as the construction of new railway and the relocation of existing line increase, tunnel structures get longer. The railway fire accidents in long tunnel bring large damages of human life and disaster. The interest on safety in long tunnel has been growing and the safety standard for long tunnels is tightening. For that reason, at the planning stage of a long tunnel, the optimum design of safety facility for minimizing the risks and satisfying the safety standard is required. For the reasonable design of a long railway tunnel considering high safety, qualitative estimation for tunnel safely is required. In this study, QRA (Quantitative Risk Analysis) technique is applied to design of a long railway tunnel for assuring the safety function and estimating the risk of safety. The case study for safety design was carried out to verify the QRA technique for two railway tunnels.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.609-617
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• 2017

Railways are one of the safest and most important transportation systems in the world. On the other hand, due to the increasing complexity of the railway system and the running distance of rail vehicles, railway accidents occur continuously every year. In particular, in the case of high-speed trains and freight trains, if the function of the axle bearing is lost due to abnormal overheating of the axle box bearing, the load on the axle becomes uneven. Therefore, abnormal overheating in the train axle box bearings can cause serious accidents or derailments. For this purpose, a Hot Box Detector (HBD) was installed in the track side of a high speed line to detect abnormal overheating. This paper proposes an EWMA technique-based axle temperature monitoring method to detect abnormal overheating quickly and efficiently. A statistical design of the proposed method was also performed. The proposed method has better performance compared to the current method in the case of abnormal overheating and the performance is improved by approximately 170% at the maximum.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.2
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• pp.117-125
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• 2015

Quantitative risk assessment (QRA) of railway is to create a variety of scenario and to quantify the degree of risk by a result of the product of accident frequency and accident. Quantitative risk Assessment is affected by various factors such as tunnel specifications, characteristics of the fire, and relation of smoke control and evacuation direction. So in this study, it is conducted that how the way of smoke control and the relation of smoke control and evacuation direction affect quantitative risk assessment with variables (the tunnel length (2, 3, 4, 5, 6 km) and the slope (5, 15, 25‰)). As the result, in a train fire at the double track tunnel (Area = $97m^2$), it is most efficient to evacuate to the opposite direction of smoke control regardless of the location of train in train fire. In addition, under the same condition, index risk in mechanical ventilation up to 1/10.

• Journal of the Korean Society for Railway
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• v.20 no.2
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• pp.173-181
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• 2017

The obstacle deflector sweeps obstacles off the track or absorbs crash energy with an energy absorber to prevent derailment of a train and to minimize damage and casualties after an accident. In this study, an obstacle deflector and its operational mechanism were designed with a tension-type energy absorber and a 4-bar linkage system. Also, a test method was suggested and verified with FEA (Finite Element Analysis) and UTM (Universal Test Machine) for testing of the static load and energy absorbing ability according to EN 15227 regulations. Through this study, an obstacle deflector that meets the EN 15227 standard was designed and a test method was suggested to adjust the collapse load easily and to verify it experimentally according to the design and verification procedure of the obstacle deflector.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1807-1813
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• 2007

The study aims at analyzing an underground station refuge model using EXODUS, one of the refuge simulation programs. The model for simulation is the Daegu Subway (Joongang-ro station). The details of the accident are referred to as the simulation condition the refuge time of traveling from the $3^{rd}$ basement platform to the $1^{st}$ basement is mainly calculated, with passengers numbering 1,000 including 329 at car 1079, 320 at car 1080, and 360 who are not on board. Reference data is used to set up the position of passengers. CFAST fire simulator is also used, and a fast curve among the $t^2$ growth curves, selected as fire growth scenario. The zone is divided into a total of 24 including 18 at the $3^{rd}$ basement platform and 6 at the $2^{nd}$ basement the $1^{st}$ basement is excluded in the fire simulation, however.