• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.595-600
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• 2007

Greater expansion and more frequent operation of the railroad transportation system anticipated due to its characteristics including low cost, safety and mass transportation. Recently, effects on the railway structures due to expansion of newly constructed road, construction of subway, city gas pipeline, communication network, electric power network and construction of other railway underground crossing in accordance with urban planning and organization has influenced safe operation of trains. Accordingly, standard for selection of construction method that will enable construction of more economical and rational subway underground crossing structures by preventing problems occurring at the time of above construction works and accidents in safe operation of trains due to construction in advance is definitively necessary. Although there are numerous construction methods that can be applied at the time of construction of railway underground crossing, there are much difficulties in selection of appropriate construction method that considers characteristics of each construction method on non-excavation type construction method, train operation plan of number of operational routes and on-site circumstances. Therefore, this research aims to present rational standard for selection of construction method for such, and standard for slowdown speed and interception of train when passing the areas of slowdown in sectors under construction.

• 한국환경보건학회지
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• 제38권6호
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• pp.529-540
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• 2012

Objective: This research was performed to evaluate the state of oil pollution in an area surrounding a railway station that has over 100 years of business history as a railway station in S City, Korea. The amount of polluted soil was estimated, and the target area for remediation was assessed in this study to restore the oil-polluted area. Methods: To accomplish this aim, five observation wells were installed for the sampling of groundwater, and soil was sampled at 33 points. Electric resistance studies and a trench investigation were undertaken to understand the geological conditions of the site, and the groundwater movement in this area was simulated by MODFLOW. Physiochemical analyses were conducted to determine the quality of the groundwater and the current state of oil pollution influenced by that of the soil. Results: The mean level of total petroleum hydrocarbons (TPHs) in this area was 1,059 mg/kg, and the area for remediation was determined to be 7,610 mg/kg. Levels of benzene, toluene, ethylbenzene, and xylene (BTEX) were determined to be under the legal standard. Conclusion: In terms of depth, the biggest area polluted by TPH found was between 0 and 1 m from ground level, and the affected area was 5,900 $m^3$. TPHs were not detected in groundwater. Diesel and lubricating oil were the main causes of TPH pollution at this railway station.

• 한국안전학회지
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• 제28권4호
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• pp.8-13
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• 2013

Fatigue crack growth tests were conducted on urban railway wheel steel under mode I and mixed-mode conditions. Fatigue crack growth rates were evaluated in terms of equivalent stress intensity factor ranges, using both the extended and projected crack lengths. The equivalent stress intensity factor range with the growth rate results obtained under mode I loading conditions can be used to predict the crack growth rate under mixed-mode loading conditions. Extended crack length rather than projected crack length is appropriate for the prediction of the crack growth rate under the mixed-mode loading conditions.

• 한국철도학회논문집
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• 제6권4호
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• pp.221-231
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• 2003

Most rail system related simulators currently used are designed to simulate only one discipline system. This obviously assumes the other discipline systems are running regularly not being affected by the system being simulated. In this paper a multi discipline simulator is proposed and its design concept is presented. A multi discipline simulator is the simulator in which major subsystems with different technical discipline are simulated simultaneously. The advantage of the simulator is in that it makes it possible to analyze the systems behavior while other discipline system vary. With this we can identify the possible multi-discipline problems and even find their solutions. A proto type simulator has been developed using object oriented programming. Object concept was judged best suitable to model the various multi-discipline self-controlling railway subsystems. It was applied to the target system, which is under development by the Korea Railroad Research Institute. The test results shows it is very useful in designn verification. It could also be a good tool in research and development work to improve the system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.46-55
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• 2008

Maglev is a system that a train runs levitated above a rail. Therefore it is very important to maintain a constant levitation gap for achieving serviceability and ride comfort. This study is a cooperation research subject of the 3-1 subject, performance improvement of maglev track structures, of the Center for Urban Maglev Program in Korea, started in 2006. The aim of this study is development of rapid constructions of bridge superstructure for maglev. At present, precast deck is widely used because of its superiority to cast-in-place concrete on quality and the term of works. The research group suggested basic systems of maglev guideway with PSC-U type and trapezoidal open steel box type girder, and precast deck, cooperating with Korea Railroad Research Institute, the managing institute of the 3-1 subject. In this study, longitudinally full-scale guideway girder system was fabricated and static/dynamic test of the girder was performed for the purpose of the performance evaluation.

• Journal of Electrical Engineering and Technology
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• 제7권1호
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• pp.115-123
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• 2012

A video analysis system used to detect events in video streams generally has several processes, including object detection, object trajectories analysis, and recognition of the trajectories by comparison with an a priori trained model. However, these processes do not work well in a complex environment that has many occlusions, mirror effects, and/or shadow effects. We propose a new approach to a context-aware video surveillance system to detect predefined contexts in video streams. The proposed system consists of two modules: a feature extractor and a context recognizer. The feature extractor calculates the moving energy that represents the amount of moving objects in a video stream and the stationary energy that represents the amount of still objects in a video stream. We represent situations and events as motion changes and stationary energy in video streams. The context recognizer determines whether predefined contexts are included in video streams using the extracted moving and stationary energies from a feature extractor. To train each context model and recognize predefined contexts in video streams, we propose and use a new ensemble classifier based on the AdaBoost algorithm, DAdaBoost, which is one of the most famous ensemble classifier algorithms. Our proposed approach is expected to be a robust method in more complex environments that have a mirror effect and/or a shadow effect.

• 전기학회논문지
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• 제68권1호
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• pp.199-206
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• 2019

Recently, an expansion of safety facilities has been widely applied to effectively manage the safety of train operation due to increase of the high-speed section of the general railway and the introduction of high-speed train. Accordingly, performance improvement, upgrading and high reliability of existing safety devices are required. the dragging detector, one of the safety devices, is an analogue system that consists of closed circuit with an electric current flows and operates when the closed circuit is opened by the impact of the dragging object. Such method has unreasonable problem that should be replaced after being detected. It is need to replace with an automatic return type dragging detector which is easy to maintain. In addition, it is necessary to develop a dragging detector that applicable to general railway and urban railway including high-speed railway, in accordance with the speeding up and densification of trains, although it is currently applied only to high-speed railway. In this paper, we propose an automatic return type dragging detector which has versatility and excellent maintainability with digital sensor and real time monitoring.

• 유통과학연구
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• 제21권9호
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• pp.93-102
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• 2023

Purpose: This study attempts to analyze the current status of the railway logistics business and to seek ways to improve it by using the business model as an analytical framework. It was intended to reflect practical implications that could be applied to the field, by dealing with issues at the industrial site related to each component in the business model. Research design, data and methodology: This study was conducted through literature review and field research. We analyzed academic papers and industrial reports on the development of the railway logistics industry and interviewed various stakeholders in the railway logistics industry. Results: This study determined the factors that could be eliminated, raised, reduced, or created from the customer and product perspective, infrastructure management perspective, and financial perspective. Conclusions: The growth of existing business can be achieved by lowering service prices, improving service quality, and securing large-scale transportation capacity. The additional transportation of high value goods and cold chain commodities will be promising business opportunities. Existing services can be provided to new customers (large pre-shippers, forwarding customers, etc.) in order to increase the size of sales Urban delivery services and comprehensive logistics services based on complex logistics centers may open an avenue for new market. A more timetable and track capacity need to be assigned to logistics, which significantly improve the flexibility and the competency of railway logistics.

• 지구물리와물리탐사
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• 제9권1호
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• pp.108-113
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• 2006

일반적인 물리탐사기법은 도심지 내에서 구조물, 전도성 지하매설물, 차량 등 인공 잡음으로 인하여 그 적용성에 많은 제약을 받는다. 특히 이 과업은 철도가 운행 중인 철로 하부의 지반 정보의 획득을 목적으로 하는데, 이를 위한 일반적인 물리탐사 적용이 어려웠으며 그 대안으로 선형배열 상시진동 탄성파탐사를 적용하였다. 상시진동 탐사(mircotremor survey)기법에는 철로를 운행하는 기차와 주변 도로의 차량에 의한 진동이 오히려 양호한 송신원으로 활용 될 수 있다. 선형배열 상시진동 탐사기법에서는 일반적인 굴절법 장비를 이용하여 일상적인 진동을 기록하고, 파동장의 변환을 수행하여 표면파의 분산곡선을 얻는다. 이후 발췌한 분산곡선에 대한 반복적인 수치모델링을 통하여 전단파 속도를 구한다. 이 과업에서는 기존 철로를 따라 하부의 터널심도까지의 전단파 속도를 전체 터널구간에 대하여 얻기 위하여 40 m 간격으로 선형배열을 이동하면서 자료를 획득하였다. 측선상의 시추를 통하여 회수한 코어를 이용한 실내시험을 통한 RMR 의 구성요소 중 하나인 일축압축강도와 전단파 속도와의 높은 상관관계를 확인하여 RMR이 전단파 속도와 연관성이 있음을 유추할 수 있었다. 시추공에서 수행한 SPS 검층에서 획득한 전단파 속도와 RMR의 비교한 결과 전단파 속도와 RMR이 높은 상관관계에 있음을 확인할 수 있었다. 상시진동 탐사기법을 통하여 획득한 전단파 속도 역시 RMR과의 양호한 상관관계를 나타냄을 알 수 있었다. 이러한 상관관계를 이용하여 도심지 철도터널 전체 구간에서 터널 설계시 필수적인 암반분류를 위한 RMR 추정이 가능하였다.

• 한국철도학회논문집
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• 제20권4호
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• pp.433-439
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• 2017

도시철도터널은 전동차 운행으로 바닥 먼지가 비산되거나 새로 발생된 마모 먼지로 오염되고 있다. 전동차가 운행하면서 이러한 부유 먼지를 제거하기 위해서 관성집진기인 배플과 전기집진기로 구성된 하이브리드형 집진장치를 개발하였다. 하이브리드형 집진장치의 유량과 집진효율은 서로 반비례하므로, 유량과 집진효율의 관계를 파악하기 위해 2가지 배플 모델을 제작하여 성능을 평가하였다. 유속이 3.4 m/s인 A1 모델을 장착한 집진장치의 $0.5{\mu}m$ 이상인 입자의 집진효율은 30% 이상이었고, 유속이 4.7 m/s인 A2 모델의 경우 20% 이상이었다. 인가전압이 13 kV일 때 1시간 동안 A1 모델 집진장치의 $PM_{10}$ 집진량은 253 mg, A2 모델의 경우 242 mg으로 추정되었다.