• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1731-1737
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• 2007

This paper considers subway routing problem. Given a schedule of train to be routed by a railway stock, the routing problem determines a sequence of trains while satisfying turnaround time and maintenance restrictions. Generally, the solution of routing problem is generated from set partition formulation solved by column generation method, a typical integer programming approach for train-set. However, we find the characteristics of metropolitan subway which has a simple rail network, a few end stations and 13 departure-arrival patterns. We reflect a turn-around constraint due to spatial limitations has no existence in conventional railroad. Our objective is to minimize the number of daily train-sets. In this paper, we develop two basic techniques that solve the subway routing problem in a reasonable time. In first stage, we formulate the routing problem as a Min-cost-flow problem. Then, in the second stage, we attempt to normalize the distance covered to each routes and reduce the travel distance using our heuristic approach. Applied to the current daily timetable, we could find the subway routings, which is an approximately 14% improvement on the number of train-sets reducing 15% of maximum traveling distance and 8% of the standard deviation.

• Journal of Intelligence and Information Systems
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• v.5 no.1
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• pp.81-93
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• 1999

열차운용이라 함은 열차의 출발과 도착 시간을 나타내는 열차번호들에 여러 객차들로 구성된 하나의 열차를 일컫는 열차 다이아(train DIAgram)들을 여러 제약조건을 고려하여 배정함으로서 열차 번호가 열차 다이아에 의해 운행될 수 있도록 열차운용 다이아를 작성하는 작업이다. 이러한 작업을 다수의 스케줄링 전문가들이 스케줄링 할 경우 많은 시간과 노력을 감수해야만 하며, 전문가의 실수로 인해 오류가 발생할 가능성이 있다. 뿐만 아니라, 복잡한 스케줄의 특성상 운용 비용이 적게 드는 스케줄 결과를 이끌어 내기가 어렵다. 본 연구에서는 열차운용 시스템을 구성하기 위해서 현재 철도청에서 사용하는 시스템을 분석하여, 열차운용 스케줄링 시스템을 모델링 하였고, 이에 모델링한 시스템을 바탕으로 CSP(Constraint Satisfaction Problems: 제약조건 만족 문제) 해결 기법을 적용하여 계산시간 및 계산 복잡성 면에서 효율적인 스케줄링을 행함과 동시에 비용 최적 함수를 적용함으로서 열차 운용 비용이 최소가 되는 열차운용 스케줄링 시스템을 구현하였다. 더불어, 시스템모델 검증과정의 하나로 과거 운용되었던 새마을호 열차시간표와 열차 데이터를 사용하여 열차 운용 및 운용 비용의 최적화를 실험하였다.

• 시스템엔지니어링워크숍
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• s.1
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• pp.140-144
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• 2003

AGT 시스템은 복잡한 대규모 시스템이며 이 시스템에 도입된 무인운전의 운영 개념은 한국 철도 기술의 환경에서는 처음 시도되는 기술이다. 게다가 신호시스템을 무선 기술을 이용하여 구현해 한다는 요구사항이 추가되어 신호시스템 개발은 더욱 도전적인 문제가 되었다. 이와 같이 실천하기 어려운 요구사항이 많은 무선열차 제어시스템 개발의 위험을 줄이기 위해 시스템공학팀은 전산지원 시스템공학 도구를 사용한 재공학의 개발공정을 수행하도록 하였다. 본 연구에서는 기존의 정적인 데이터모텔에 추가하여 시나리오 기반으로 동적거동 분석을 수행하여 기능 모델을 구축하였고 기능 모델을 토대로 한 시스템 아키텍처를 구성하였다. 특히 기능 요구사항의 취약성을 보완하기 위해 CORE의 FFBD(Functional Flow Block Diagram)기능을 활용하여 열차 운행 중 발생할 수 있는 여러 가지 시나리오를 분석함으로써 기능 모델의 완전성의 기여하였다. 이는 정적인 데이터 흐름 다이아그램(DFD:Data Flow Diagram)이 가지는 한계를 모델 기반 시스템공학 도구에서 지원하는 동적인 기능 분석을 수행하여 보완함으로써 모델의 충실도를 높였음을 의미한다. 이를 통해 기능의 오류를 개념단계에서 최소화함으로써 기술 위험이 높은 제품을 개발할 수 있다는 것을 확인하였다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.364-366
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• 2007

본 논문은 철도차량이 주행하는 선로에 존재하는 수많은 곡선과 경사, 속도 제한 조건 때문에 열차성능해석 계산시 열차의 견인, 제동 특성이 비선형이기 때문에 해석적인 방법으로 해를 구하는데 어려움이 많은 경제운전 문제를 운행 시간 여유분을 고려하여 에너지 소비를 최소화하는 운전 모형을 제시한다. 경제운전모형을 한국형 고속열차에 적용하여 그 타당성을 입증하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2011.01a
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• pp.107-108
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• 2011

Since the development of railway technology, the current urban Railway the first train line in the country for safe operation control automatic/unattended operation, automatic train operation equipment available (ATO) on time and reliable operation has introduced. ATO Automatic operation controlled by the value (Target velocity) and the feedback value (Actual velocity) by the error between the backing and braking of the train by repeated low energy efficiency. In this paper, given a fixed distance stations between time operation with minimal energy in the driving characteristics and driving trains are modeled. Therefore, in line 5 real route time sectional drive straight sections for experimental data analysis / draft Section / curved and section of the train on that line is selected according to the changing driving patterns to minimize the energy optimal driving patterns were presented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.603-610
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• 2016

Over 12 years have passed since the first commercial operation of a Korean high-speed train. Since then, the transport capacity of the high-speed lines has become almost saturated. Therefore, studies have been carried out to increase the operating speed of the trains in order to increase their transportation capacity. This study was carried out to improve the critical speed of the KTX-Sancheon, Korean high-speed train, in order to increase its operating speed. A dynamic analysis of the KTX-Sancheon train was performed using the contact data obtained from the wheel wear profiles that were measured from a KTX-Sancheon train in commercial operation. The analysis results were verified by comparing them with the measurement acceleration data obtained from KTX-Sancheon. The suspension parameters were optimized to improve the operation speed. The critical speed of KTX-Sancheon was increased by 9.4% after the optimization by the response surface method. The optimized suspension parameters are expected to be used for the new bogie design to increase the operating speed of KTX-Sancheon from 300km/h to 350km/h.

• Journal of the Korean Society for Railway
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• v.13 no.3
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• pp.290-297
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• 2010

At present, the design live load of railway is divided into common railway and high speed railway separately in Korea. L22 which is based on American railway standards is used for common railway and HL25 which is based on Eurocode is used for high speed railway. Although, the design load is the starting point for design of railway, any research for developing design load does not exist at all. However, Europe and Japan develops the design load model consistently for advanced design. Recently, deterministic, probabilistic and cost performance approaches are investigated for developing new design load in Europe which is called LM2000. In the present paper, as a step for developing new design live load model for Korean railway, deterministic processes will be introduced. The safety margins are analyzed based on serviced real trains versus proposed new design load model and a necessity for new design live load will be presented quantitatively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2985-2991
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• 2013

Train radio system has been constructed in the second stage of Kyung-bu high speed railway adopting TETRA(Terrestial trunk radio) standard at 851MHz frequency band. The base stations of the train radio system should be located along railway track to ensure seamless communication between train and wayside taking the path loss of train radio propagation into consideration. This paper provides a quantitative analysis of the path loss characteristics based on the measurement results of the train radio propagation along the high speed railway. The free space propagation model and Okumura-Hata model are generally used for base station design, but they predicted 10dB lower or 20dB higher than the measured path loss. Linear regression of the field measured data by applying the log-distance model shows path loss exponent is in the 2.8-3.2 range, which can be used to predict the path loss of the train radio propagation.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.953-960
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• 2009

In the major operation section of urban railway, there has been occurred habitual delay, and delay propagation and spread to consecutive trains. Therefore, this delay cause the increase of operation time and irregular operation, also the increase of crowd and inconvenience to passengers. The railway operation plan is a promise to passengers and must have reliability. In the case of high frequency urban operation, dwell time have considerable influence on operational headway, so it is very important to efficiently plan and control the dwell time at stations. In this paper, the survey of the research on dwell time for urban railways is presented. The practical estimation model for minimum required dwell time, and the numerical example and validity are proposed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.887-895
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• 2018

This paper presents a braking model that can be used to design the safety distance of a train control system and a train braking system to increase the volume of traffic. For the braking model, a train set (electric multiple unit composed 6 cars) was tested. The factors that can affect the braking characteristics include the friction coefficient, braking pressure, and regenerative braking. The braking pressure was classified into service and emergency braking and reflected the characteristics of the vehicle. The external force acting on the running railway car was tested in accordance with KS R 9217, and the running resistance of the train is presented in the form of a polynomial. The dynamic behavior of the train running on a straight flat line was simulated using UM 8.3. The results were validated with experimental data, and the results were reasonable. With the validated model, a stopping distance was determined according to the initial braking speed and compared with the deceleration braking model. In addition, a safety distance for the train control system could be changed according to the frictional coefficient limits. These results are expected to be useful for analyzing the dynamic behavior of trains, and for analyzing various railway environments and improving the braking performance.