• Wind and Structures
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• v.29 no.3
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• pp.149-161
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• 2019

When a railway vehicle runs in crosswinds, the unsteady aerodynamic forces acting on the train induced by the vehicle speed, crosswind velocity and local landforms are a common problem. To investigate the dynamic performance of a railway vehicle due to the influence of unsteady aerodynamic forces caused by local landforms, a vehicle aerodynamic model and vehicle dynamic model were established. Then, a wind-loaded vehicle system model was presented and validated. Based on the wind-loaded vehicle system model, the dynamic response performance of the vehicle, including safety indexes and vibration characteristics, was examined in detail. Finally, the effects of the crosswind velocity and vehicle speed on the dynamic response performance of the vehicle system were analyzed and compared.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.769-774
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• 2010

KTX Introduced in korea have occurred enhanced services and reduced regional travel time. "Induced traffic" is defined in the traffic demand generated in new project. 'Induced traffic' compared to the Diversion Demand Survey and research on ways to quantify the situation, insufficient analysis of constant and long-term observations are needed to estimate the changes in demand. In this study, Induced traffic effects due to the opening of KTX for analysis survey to passengers by Railway and the scale factor induced traffic review.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1416-1423
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• 2007

Dynamic instability of the railway bridge can cause track irregularities and be directly connected with unstable passenger comfort and derailment of the train. Europe and Japan had studied on this problem for a long time since 1960's, Results of those studies are reflected in recent Eurocode and the bridge design code of Japanese railway bridges. However, even though some traffic safety requirements were applied in Kyoung-bu highspeed railway by French engineers, we experienced many difficulties from insufficient information of criteria background and application procedures. In this paper, a investigation of recent traffic safety requirements of Europe and Japan for railway bridges will be introduced and application procedures for the estimation of dynamic performance will be proposed.

• Journal of the Korean Society for Railway
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• v.14 no.3
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• pp.276-284
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• 2011

In our study, we present a new LOGIT-based traffic assignment model applicable to intercity railway network. Most traffic assignment models have been developed for public transit assignment in urban area, so that they are known to produce unrealistic results in intercity railway demand analysis. Especially, since the introduction of KTX, more passengers are using a route including KTX service and the schedule becomes more compatible with transfer. Our study presents a new LOGIT-based traffic assignment model considering passenger transfer. To do so, we suggest a new route search algorithm to find K paths with non increasing order in the utility value.

• ETRI Journal
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• v.40 no.1
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• pp.39-50
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• 2018

More people prefer using rail traffic for travel or for commuting owing to its convenience and flexibility. The railway scenario has become an important communication scenario in the fifth generation era. The communication system should be designed to support high-data-rate demands with seamless connectivity at a high mobility. In this paper, the channel characteristics are studied and modeled for the railway tunnel scenario with straight and curved route shapes. On the basis of measurements using the "Mobile Hotspot Network" system, a three-dimensional ray tracer (RT) is calibrated and validated for the target scenarios. More channel characteristics are explored via RT simulations at 25.25 GHz with a 500-MHz bandwidth. The key channel parameters are extracted, provided, and incorporated into a 3rd-Generation-Partnership-Project-like stochastic channel generator. The necessary channel information can be practically realized, which can support the link-level and system-level design of the communication system in similar scenarios.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.527-530
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• 2017

LTE-R(Long Term Evolution-Railway) based on LTE technology is expected to use core communication technology for high speed railway as one of standards for railway communications. In this paper, transmission performance of video traffic as an application is analyzed on LTE-R networks. Performance is evaluated with compter simulation based NS(Network Simulator)-2, open video traffic is used, RTP(Real Time Protocol) is used for transmission protocol. Results and methods of this paper can be used for research and developmemt of LTE-R networks.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.825-830
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• 2005

Traffic control is the center of the railway traffic control system. The main objective of railway traffic control system is to minimize delays, providing the customers with on-time train operating service according to the given train schedule. Particularly, within the station control area, the departure & arrival of train. the decision on the train priority and the shunting of train are decided by the authority of the local traffic controller. Therefore, it is necessary to have a lot of information and communications between each departments. And for such decision making of the local traffic controller, not only the communication between each stations are needed, but also the communication between other stations are needed too. In this paper, we have analyzed the main work of the local traffic controller in large scale stations and have designed the station traffic control system needed to be built within the station considering the local traffic. And we have proposed not only the communication with other system within station, but also the communication methods for communications with the neighboring stations.

• Wind and Structures
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• v.35 no.5
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• pp.309-322
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• 2022

Due to the complex terrain around high-speed railways, the windbreaks were established along different landforms, resulting in irregular windbreak transition regions between different subgrade infrastructures (flat ground, cutting, embankment, etc). In this paper, the effect of a windbreak transition on the wind flow around railways subjected to crosswinds was studied. Wind tunnel testing was conducted to study the wind speed change around a windbreak transition on flat ground with a uniform wind speed inflow, and the collected data were used to validate a numerical simulation based on a detached eddy simulation method. The validated numerical method was then used to investigate the effect of the windbreak transition from the flat ground to cutting (the "cutting" is a railway subgrade type formed by digging down from the original ground) for three different wind incidence angles of 90°, 75°, and 105°. The deterioration mechanism of the flow fields and the reasons behind the occurrence of the peak wind velocities were explained in detail. The results showed that for the windbreak transition on flat ground, the impact was small. For the transition from the flat ground to the cutting, the influence was relatively large. The significant increase in the wind speeds was due to the right-angle structure of the windbreak transition, which resulted in sudden changes of the wind velocity as well as the direction. In addition, the height mismatch in the transition region worsened the protective effect of a typical windbreak.

• Journal of the Korean Society for Railway
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• v.17 no.2
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• pp.140-147
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• 2014

Line planning is an important step to determine the optimal frequencies of trains given the forecasted demand for each train type. The main input data for line planning is the leg traffic demand which can be derived using suitable traffic assignment models. However most assignment models require a line plan, in other words, train frequencies or headways, so that inconsistent results just by the procedural approach to find an optimal line plan after determining leg traffic can be avoided. This paper suggests a unified model that can consider the traffic assignment and line planning, simultaneously. We further provide an elaborated approximation algorithm and, finally, provide experimental results determined for the Korean railway network.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.2108-2115
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• 2008

Using transportations like railway, aviations and roads has been increasing continuously. Traffic accidents have been increasing as well. To prevent or lessen these accidents become a big issue to solve. Therefore, more enforced safety levels are being required to meet. In railway field, continuous efforts of railway safety are being executed to prevent traffic accidents. In present, a railway accident has been decreasing since subway accident happened in Daegu Subway in 2003. However, safety levels in railway field have not yet achieved as much as in advanced countries. Basic concept for enforced safety level in railway system is to prevent or minimize accidents by managing systems like related facilities, management method, organization, education. This is the same concept to minimize error rate in six sigma theory. In this paper, we are to apply six sigma techniques used in manufacturing industry to railway safety and go through ways to make more efficient railway safety system.