• Journal of the Korean Society for Railway
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• v.18 no.6
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• pp.619-629
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• 2015

The train conflict resolution problem refers to an adjustment of the train operation schedule in order to minimize the delay propagation when a train conflict is predicted or when a train conflict occurs. Previous train studies of train conflict resolutions are limited in terms of the size of the problems to be solved due to exponential increases in the variables. In this paper, we propose a train conflict resolution model using a time-space network to solve the train conflict situation in the operational phase. The proposed model adjusts the size of the problem by giving only the dwell tolerance in the time-space network only for stops at the station after a train conflict. In addition, the proposed model can solve large problems using a path flow variable. The study presents a train delay propagation analysis and experimental results of train conflict resolution assessments as well using the proposed model.

• Journal of the Korean Society for Railway
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• v.20 no.1
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• pp.142-155
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• 2017

It is anticipated that, in cases in which different train operators share railway network, conflicts may occur among train operators with regard to train operation rate, train priorities, and arrival and departure time; besides this, during times when there is high demand for trains, operators will request train operations intensively, steadily increasing train conflict phenomena. In the present study, train operation sequence, minimum headway, arrival and departure time, train priorities, etc., were analyzed, and while using train departure times as decision variables in variably given train schedules, by adjusting train time requested by train operators, and finally rejecting the train times in cases in which conflict resolution is impossible, so that various constraints can be satisfied, a train slot allocation model was suggested to find the objective function, that is, the maximum number of train slots that can be practically applicable to railway operation.

• Journal of the Korean Society for Railway
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• v.10 no.2 s.39
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• pp.179-185
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• 2007

In large station with high density traffic, trains can be hardly controlled by CTC but by station dispatcher because CTC has difficulties in monitoring all states of affairs happening within each station such as departures, arrivals of many trains from different lines and shunting of trains to move between yards and platforms, etc. Therefore the station's dispatcher has to make quick decision about how to reschedule the times and routes for all the trains scheduled within a specific time window. And such decision becomes harder when an unexpected delay occurs because a delay occurring in a train propagates other trains as time goes on. Generally, it is called the conflict detection and resolution to adjust beforehand the distorted schedule due to a delay to original schedule. Our research is different from the state of the arts in that ours determines simultaneously the routes and the times of arrival and departure of trains, although others do only the arrival and departure time of the trains without considering the alternative routes and shunting of the station. This study suggests a mathematical approach for how to detect in advance and resolve efficiently the conflicts occurring within a station and it will be shown how to reduce delay using our approach by means of analysing the schedule of ChyungRyangRi station.

• Journal of the Korean Society for Railway
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• v.8 no.4
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• pp.314-320
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• 2005

This paper is designed to help train dispatcher resolve railway conflicts in rent-time. We developed a mixed integer programming model to optimize the train schedule that determines the best overtaking or crossing positions, The objective of the model is to minimize the maximum lateness of the trains and reduce the total sum of the lateness, while satisfying the field constraints associated with the difference between passenger trains and freight trains, and the limited number of sidings. We applied the model on a portion of a single line track, Joong-Ang Line to ascertain the efficiency of the model, and showed how the model can be used to resolve the railway conflicts. The results indicates that our model can provide useful results in terms of optimal schedule for the test problem. This type of modeling approach would be useful for a train dispatcher to make a real-time railway conflict resolution.

• Journal of the Ergonomics Society of Korea
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• v.27 no.1
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• pp.1-7
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• 2008

Work related musculoskeletal disorders (WMSDs) have become a hot issue within the Korean workplace for the past several years. Recently, the effect of job related stress on WMSDs, cerebro-cardiovascular diseases, and psychiatric disorders has been steadily increasing. The study conducted questionnaire of Korea version job stress model, WMSDs from NIOSH, CES-D (Center for Epidemiologic Studies Depression Scale), and STAI (State-Trait Anxiety Inventory) against train drivers. The results of this study show that the job stress score of the train drivers is high in the areas of physical environment, job latitude, interpersonal conflict, job insecurity, and organization system. The relation between job stress and WMSDs nd, interpersonal conflict, job insecurity and organizational system. The relation between job stress and depressive disorders showed statistical significance in the areas of job demand, job insecurity and low reward. Finally, the relation between job stress and anxiety disorders showed statistical significance in areas of job demand, interpersonal conflict, job insecurity, organizational system and low reward.

• Journal of the Korea Safety Management & Science
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• v.16 no.4
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• pp.91-99
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• 2014

This study highlights the theme of human error of train drivers, conducting empirical analysis on the relationship between organizational culture, safety climates, safety behavior, and accident. The empirical test results based on questionnaires received from 223 train drivers working at A subway firm indicated that relationship conflict and psychological reward as the elements of organizational culture variables showed a significant positive effect on CEO philosophy, communication, and boss's leadership. And only boss's leadership showed a positive influence on safety behavior, which in turn showed a significant negative relationship with accidents.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.634-643
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• 2011

The neutral section was installed in order to prevent conflict with different phase angle source in electric railway catenary system. The speed of electric train reduced due to coasting operation by notch off when it passed the neutral section. And, the catenary wire was damaged and the accident might be happened because of the arc generation when the electric train passed the neutral section with notch off condition. The inrush current of main transformer installed tiling train is analyzed during the operation of MCB(main circuit break) passing through the neutral section. The instantaneous waveform of load current were analyzed in case of powering and regenerative braking. Inrush current waveform with run of AC railway train showed that inrush current waveform and harmonics, the inrush current generated from main transformer in train has bad effects on power quality problem. In order to reduce these inrush currents, the MCB is connected when the phase angle of voltage is 90 degree. This paper is to measure inrush current and harmonics in main transformer of high speed train in neutral section of electric railway. This measurement report is used to control minimum inrush current in algorithm and power phase angle.

• Journal of the Korean Society for Railway
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• v.10 no.3 s.40
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• pp.257-263
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• 2007

The critical speed above which the vehicle become unstable is one of the items that should be verified in the development of a new train. In the case of a high speed tilting train, which requires both higher critical speed and higher curving speed, the critical speed should be more carefully treated because the both requirements are in conflict with each other in the conventional train design. The main purpose of the present work is to estimate the linear and non-linear critical speeds of 200km/h Korean Tilting Train 'Hanbit200' under development. The newly developed self-steering mechanism was attached to the tilting train to ensure that the critical speed falls under the lower yaw stiffness which is needed to secure higher curving performance. The simulation for predicting the critical speed was done by a commercially available vehicle dynamics software. A full scale roller rig test was carried out to validate the numerical results and to verify the effectiveness of the self-steering mechanism.

• Journal of Computing Science and Engineering
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• v.9 no.2
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• pp.98-107
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• 2015

Hierarchical constraints and constraint satisfaction were analyzed in order to solve the problem of conflict detection in collaborative design. The constraints were divided into two sets: one set consisted of known constraints and the other of unknown constraints. The constraints of the two sets were detected with corresponding methods. The set of the known constraints was detected using an interval propagation algorithm, a back propagation (BP) neural network was proposed to detect the set with the unknown constraints. An immune algorithm (IA) was utilized to optimize the weights and the thresholds of the BP neural network, and the steps were designed for the optimization process. The results of the simulation indicated that the BP neural network that was optimized by IA has a better performance in terms of convergent speed and global searching ability than a genetic algorithm. The constraints were described using the eXtensible Markup Language (XML) for computers to be able to automatically recognize and establish the constraint network. The implementation of the conflict detection system was designed based on constraint satisfaction. A wind planetary gear train is taken as an example of collaborative design with a conflict detection system.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.498-506
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• 2010

The neutral section was installed in order to prevent conflict with different phase angle source in electric railway catenary system. The speed of electric train reduced due to coasting operation by notch off when it passed the neutral section. And, the catenary wire was damaged and the accident might be happened because of the arc generation when the electric train passed the neutral section with notch on condition. This project has a goal to develop the automatic changeover system using by noncontactless semiconductor device in neutral section of catenary system so that the train pass as notch-on condition. In this first year, we obtain as following results such as domestic and international systems applications and completion requirements, development and analysis of stability for automatic changeover system, design of static switching device on automatic changeover system in neutral section and drawing up interface design and specifications according to equipment.