• 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.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.9
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• pp.545-551
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• 2004

CBTC(Communication Based Train Control) System can improve train operation efficiency by realizing moving block system which makes a continuous train interval control in accordance with the position and speed of train. Adopting radio transmission to make a continuous detection of train position and transmit the control data from the ground to a train, CBTC needs dedicated train operation and control algorithm which should be quite different from the conventional track-circuit-based train control system. This paper provides a train operation display and control algorithm for CBTC system in making train interval control, train route control and train supervision. Signalling pattern diagram is devised to analyze the train interval control mechanism of moving block system, and interlocking logic is devised to represent the train route control mechanism of moving block system. For train supervision, train occupation status on railway are displayed by using the segment which virtually divide the whole railway. The proposed method has been successfully applied to the development of CBTC system for the standardized AGT(automatic guided transit) which is under construction now in Korea, and also can be applied to any other CBTC system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6949-6958
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• 2015

Radio based train control system performs train safe interval control by receiving in realtime the position information of trains driving in the control area of the wayside system and providing onboard system in each train with updated movement authority. The performance of the train control system is evaluated to calculate the minimum operation headway, which reflects the operation characteristics and the characteristics of the train as well as the interval control performance of the train control system. In this paper, we propose the operation headway calculation for radio based train control system and a new train interval control algorithm to improve the operation headway. The proposed headway calculation defines line headway and station headway by the estimation the safety margin distance reflecting the performance of the train control system. Furthermore the proposed Enhanced Train Interval Control(ETIC) algorithm defines a new movement authority including both distance and speed, and improves the train operation headway by using braking distance occurring inevitably in the preceding train. The proposed operation headway calculation is simulated with Korean Radio-based Train Control System(KRTCS) and the simulated result is compared to improved train interval control algorithm. According to the simulated results, the proposed operation headway calculation can be used as performance indicator for radio based train control system, and the improved train control algorithm can improve the line and station headway of the conventional radio based train control system.

• 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.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.330-333
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• 2002

Even if the train of subway starts in a certain interval from the origin according to the operation plan. as the number of passenger gets increased during operation. the boarding and getting-off time will increase, and the temporary breakdown happens to the system of train during operation, causing the delay from the operation plan. this leads to the vicious circle of train operation. making the interval of train operation irregular in downtown especially. To solve this problem, we propose the method of advanced algorithm by the actual data relating to the train operation including operation time required between stations, distance between stations. capability of train, and the dwelling time, location and distance between the preceding train and next one. The central train control system adjusts the dwelling time at each station in order to recover the delayed time, and increase the operation speed at the each station. As control algorithm is applied the dwelling time and to increase the speed, the train maintains certain interval after certain amount of time passes.

• 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.

• Structural Engineering and Mechanics
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• v.59 no.2
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• pp.277-290
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• 2016

This paper investigates the ground vibration induced by high-speed trains moving on multi-span continuous bridges. The dynamic impact factor of multi-span continuous bridges under trainloads was first determined in the parametric study, which shows that the dynamic impact factor will be large when the first bridge vertical natural frequency is equal to the trainload dominant frequencies, nV/D, where n is a positive integer, V is the train speed, and D is the train carriage interval. In addition, more continuous spans will produce smaller dynamic impact factors at this resonance condition. Based on the results of three-dimensional finite element analyses using the soil-structure interaction for realistic high-speed railway bridges, we suggest that the bridge span be set at 1.4 to 1.5 times the carriage interval for simply supported bridges. If not, the use of four or more-than-four-span continuous bridges is suggested to reduce the train-induced vibration. This study also indicates that the vibration in the train is major generated from the rail irregularities and that from the bridge deformation is not dominant.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.2
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• pp.67-76
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• 1999

Resonance of the bridge can be occurred with the coincidence between a natural frequency of the bridge and a crossing frequency of moving loads which is determined from the speed and effective beating interval of the vehicle. In case of the railway bridge, the effective beating interval of the vehicle is fixed under the passage of specific trains. In the present study, resonance and cancellation of the bridge subjected to moving high-speed train are analyzed with the variations of span length. A steel-concrete composite railway bridge is idealized by the combinations of plate elements and space frame elements. High-speed train is idealized with moving constant forces and a 3-dimensional full modelling. From analyzing dynamic responses of D.M.F of vertical displacement, maximum vertical acceleration of the slab, and end rotation according to the variations of span length of the bridge, design criteria of span length of the bridge which satisfies dynamic safety is discussed.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.176-176
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• 2000

Generally, discrete-time processing is applied to the uniformly-sampled signals. But, radars emit pulse trains with irregular time instances. In this paper, we formulate the radar pulse train as a stochastic discrete-time dynamic linear model. The estimation task can be done via linear signal processing using Kalman Filter and some considerations. As a result, we can estimate the pulse repetition interval of a pulse train and predict the time instances of the next pulses to be received.

• The Journal of Korean Physical Therapy
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• v.14 no.4
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• pp.398-411
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• 2002

Objectives: The purpose of present study was to investigate the experience and point prevalence rate and factors related with Low Back Pain (LBP) in train egineers. Methods: Questionnaires were completed by 324 train engineers in Daejeon railroad administration from May 2002. The information was used to estimate odds ratio (OR) and 95$\%$ confidence intervals (CI) for factors relation to LBP. A retrospective study design was used. Results: The experience rate for LBP was 67.9$\%$, 54$\%$ in one year interval prevalence, 53.4$\%$ in 6 months interval prevalence, and 47.8$\%$ in a point prevalence rate. Variables significantly associated with LBP experience were age (p=0.0327), train vibration(p=0.0015), labour hour(p=0.0034), and pay(p=0.0534). As subjects got older, the higher experience for LBP was (OR=1.1, 95$\%$ CI 1.0-1.2). LBP experience rate for people who had felt train vibration was a higher than those who did not (OR=2.5, 95$\%$ CI 1.4-4.4, OR=2.3 95$\%$ CI 1.3-4.0 in a point prevalence). The people who worked for long hour was a higher than those who did not (OR=2.8, 95$\%$ CI 1.4-5.6, OR=2.2, 95$\%$ CI 1.1-4.5 in a point prevalence). The people who were not satisfied with pay was a higher than those who were (OR=1.7, 95$\%$ CI 1.0-3.0). Factors related to a point prevalence rate were train vibration(p=0.0027), chair vibration (p=0.0444), and labour hour(p=0.0340). LBP a point prevalence rate for people who had felt the vibration of train chair was a higher than those who did not (OR=1.8 95$\%$ CI 0.7-2.0). Conclusions: Results from present study indicated that a statistically significant factors associated with LBP experience were age, train vibration, labour hour, and pay, Factors related to a point prevalence rate were also train vibration, the vibration of train chair, and labour hour.