• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1426-1440
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• 2008

In Korea, the concentration for the use of urban railroads is comparatively high during peak hours. In case of road traffic, overcrowdness leads the increase of total travel time and cost naturally but this does not happen in railroad systems because of fixed operational interval. Thus, passenger's disutility is generated physically and mentally from congestion increment. The increase of railroad capacity from new transit lines and expansion of existed lines contributes traveler's comfort benefits to rising. However, present evaluation guidelines for feasibility studies of road and railroad projects do not include any valuation methodology about passenger's comfort benefits. Therefore, in this research, various factors affecting comfort benefits are reviewed and stated preference survey is performed in order to estimate traveler's comfort benefits for congestion reduction. In addition, willingness to pay for congestion avoidance is calculated from that stated preference survey based on Tobit Model. As a result, detailed unit for willingness to pay according to congestion reduction is proposed in this study.

• Journal of the Korean Society for Railway
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• v.18 no.5
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• pp.419-425
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• 2015

When a train is delayed because of a disturbance, the time interval between successive trains increases and high-frequency metro lines can become unstable. Time interval control is therefore necessary in preventing such instabilities. In this paper, we propose an optimal interval control algorithm that is easy-to-implement and that guarantees system stability. In the proposed method, the controlled trains are determined from the time interval deviations between successive trains; the control algorithm for staying time is designed by use of a discrete traffic model to ensure an optimal time interval between successive trains. The results of a computer simulation are also given to demonstrate the validity of the proposed algorithm.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.3
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• pp.29-36
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• 2002

Recently, power quality problems in AC high-Speed Railway system have been raised, because heavy train and its higher speed are required in addition to new control system by using the Electronic devices. The installation/operation of the Series Capacitor(SC) has been only a device far voltage drop in power system up to now. However, the sufficient effectiveness of compensating In voltage drop has not been proved yet because of technical limitationf SC, and harmonic resonance is attracting a attention as one of new issues. Several problems are expected such as vocational problems of a traction substation, and overloading caused by a new construction of electric railway and the in transport. Therefore, extension of power feeding the fault in the traction substation should be also considered. So this paper represents the application of TSC-SVC on the electric railway power feeding system as a device of voltage compensation, and the simulations are executed through PSCAD/EMTDC.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.92-92
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• 2019

최근 기존의 격자방식의 해석 방법을 벗어나 해석 영역에 대한 분할을 별도로 고려치 않는 수치기법의 실무적 적용사례가 증가 하고 있으며, 이러한 방식중 SPH(Smoothed Particle Hydrodynamics) 방식이 근자에 수자원 분야에서도 도입되어 관수로 및 개수로 해석 또는 복합해석 등에 활용된 바 있다. 최초 도입된 무격자방식의 모형들은 주로 복잡한 형상을 지니는 유체기계 등에 활용성이 높았던 바, 큰 규모의 해석 도메인을 가지는 수자원 분야에서의 SPH의 실무적용 평가와 효율성의 확보를 위해서, 본 연구는 국내 댐을 시범 대상으로 하여 SPH 수치해석 툴을 적용하고자 하였다. 분석 대상댐은 국내 P댐으로서 관리수위의 변동은 크지 않으나, 댐 직상류의 만곡이 심하고 다수의 대규모 취수구를 가진 곳으로 상시 발전방류 및 수시 댐 수문방류에 의해 유체의 흐름이 2,3차원의 복잡성을 띄고있기 때문에, 3차원 전산유체역학 Tool의 적용이 적절한 것으로 판단하였다. 해석을 위해 하류경계조건을 댐축과 문비로 설정하였고 상류 1km까지를 해석의 도메인으로 설정하였다. 소요시간을 줄이기 위해 여러 번의 모의를 거쳐 입자의 평균 입경은 0.6m로 제안하고 시격은 1초 미만(평균 0.5초)로 설정하였다. 수문 및 발전방류는 해당댐의 1~2년 빈도 수준에 해당하는 $5,000m^3/s$ 이하의 유량을 기준으로 하여 모의를 수행하였다. 모의의 안정성을 확보한 이후에는 해당 댐지역의 하류영향을 고려한 문비제어를 반영한 다양한 방식의 수문운영 및 취수지점의 순간 수위 영향을 검토하였다. 그 결과로 본 모의에서는 특정한 수문의 운영 조건에서는 댐수위 계측지점과 인근 취수지점 간에도 0.2m 수준의 순간 수위차가 발생할 수 있음을 보였으며, 이는 경우에 따라 취수시설의 일시적 장애요소로 발생할 수 있음을 의미한다. 따라서, 현재의 취수구조물과 문비운영 특성에 따라 발생가능한 취수장애를 줄일 수 있는 운영조건의 탐색을 위해서 수치모의를 추가로 하였으며, 이 때 댐축 상류의 유속분포에 대한 추가 검토도 수행하였다. 다만, 댐에서 방류시 하류조건에 대한 검토는 추후 보강되어야 할 것으로 판단된다.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1681-1698
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• 2011

According to the demands of the times, Inchon international airport railroad opened up step by step but It is situation that much government subsidies are paid because It does not competitive power with road traffic by decline of schedule speed. Inchon international airport railroad users will convert by other transportation and minimize damage their time as travel time is prolonged. Therefore, need high speedization of airport railroad, this may act big role competitive power security as well as airport railroad activation with another public transportation. Thus, this paper suggests that a high speedization possibility section in the sections of airport railroad and train speed elevation effect analysis by roadbed, railroad, system improvement and the most efficient operation intervals analyzing each vehicles (AREX (120km/h), KTX (230km/h), EMU(Electric Multiple Unit, 180km/h) train running pattern.

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.631-637
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• 2012

New Opening of Suseo-Pyeongteak High Speed Railway (HSR) will be a new leap in the Korean railway history. However if this section of HSR line around Seoul Metropolitan Area opens, the confluence of new HSR and existing HSR line in Pyeongteak-Osong section will cause a bottle neck problem. In other words, the opening of Suseo-Pyeongteak HSR line will make the capacity of track reach the limit and the section of railroad between Pyeongteak and Osong will be saturated. This will also make such troubles as restricting the number of train which stops at Cheonan-Asan station. In this study, based on the train assignment theory of TVM430 signal system, the methods of calculating headway and number of train are reviewed and the plan for application of optimal operation pattern during peak hour between Pyeongteak-Osong section is also suggested. To remove the bottle neck problem in this HSR section, 3 alternatives are suggested and the expected effects and problems of each alternative are also analyzed. The results show that the troubles caused by excess of track capacity can be removed without any additional cost if the minimum headway in operating system for HSR is adopted in this section. In the future, if these alternatives are considered to the long-term plan for operating train and signal systems, this will improve the efficiency of train operation, which can remove the bottle neck in the HSR line.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.1-9
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• 2016

Train control systems have changed from wayside electricity-centric to onboard communications-centric. The latest train control system, the CBTC system, has high efficiency for interval control based on two-way radio communications between the onboard and wayside systems. However, since the wayside system is the center of control, the number of input trains to allow a wayside system is limited, and due to the cyclic-path control flows between onboard and wayside systems, headway improvement is limited. In this paper, we propose a train interval-control and train-centric distributed interlocking algorithm for an autonomous train-driving control system. Because an autonomous train-driving control system performs interval and branch control onboard, both tracks and switches are shared resources as well as semaphore elements. The proposed autonomous train-driving control performs train interval control via direct communication between trains or between trains and track-side apparatus, instead of relying on control commands from ground control systems. The proposed interlocking algorithm newly defines the semaphore scheme using a unique key for the shared resource, and a switch that is not accessed at the same time by the interlocking system within each train. The simulated results show the proposed autonomous train-driving control system improves interval control performance, and safe train control is possible with a simplified interlocking algorithm by comparing the proposed train-centric distributed interlocking algorithm and various types of interlock logic performed in existing interlocking systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6274-6281
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• 2015

Radio-based train control system has driving headway shortening effect by real-time train interval control using two-way radio communication between onboard and wayside systems, and reduces facility investment because it does not require any track-circuit. Automatic train protection(ATP), the most significant part of the radio-based train control system, makes sure a safe distance between preceding and following trains, based on real-time train location tracing. In this paper, we propose the overall ATP train interval control algorithm to control the safe interval between trains, and preprocessing-based speed profile calculation algorithm to improve the processing speed of the ATP. The proposed speed profile calculation algorithm calculates the permanent speed limit for track and train in advance and uses as the most restrictive speed profile. If the temporary speed limit is generated for a particular track section, it reflects the temporary speed limit to pre-calculated speed profile and improves calculation performance by updating the speed profile for the corresponding track section. To evaluate the performance of the proposed speed profile calculation algorithm, we analyze the proposed algorithm with O-notation and we can find that it is possible to improve the time complexity than the existing one. To verify the proposed ATP train interval control algorithm, we build the train interval control simulator. The experimental results show the safe train interval control is carried out in a variety of operating conditions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.679-686
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• 2006

Recently, the city railway in the Seoul Metropolitan Area (SMA) has offered a low quality of service as a passage time, because it was operated slowly. So, the people who live in modern society are not satisfied about passage time, therefore, this study tried to make that the subway in the SMA becomes a more functional and effective wide-area-transportation-network through an express train introduction's method which examined cases from abroad and current system. and then presented how express train could be applied to current system. In a case study, We used the An-San Line and Su-In Line as a examples and developed a schedule which can minimize the delaying time of subway by using Branch & Bound Algorithm. The train operational plan was loaded to consider a railroad siding, Obtained site, and the dispatch interval(three to ten minutes) for the express and local lines and finally, We presented an alternative operational plan which made by those factors.