• Proceedings of the KSR Conference
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• 2011.05a
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• pp.145-153
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• 2011

In the system necessary for safety such as the train control system, to make train control information be sent correctly is very important to enable organic movement between trains. In the case of the system such as RF-CBTC (Radio Frequency Communication Based Train Control) the control related information is sent through wireless transmission between on-board system of a train and wayside transmitter. The wayside transmitter collects the running information such as location, velocity from the on-board system and operates the optimizing control by sending the control information such as the target, limited velocity to the on-board system. But, when the communication disconnect or train failure, the critical hazard such as train collision or derailment may be possible because the RF-CBTC depends on the information through wireless communication. This paper discribes of performing Fall-Back system to detect train position in the case of rail break or communication failure to avoid train accident and allows train to be operated safely. It can be implemented with ATP function through track circuits using active-type transformers and axle counters, and allows train to be operated manually in emergency status.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1199-1204
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• 2004

In this paper, the DCS (Data Communication System) which is a main part of CBTC (Communication Based Train Control) system is consisted of radio based wireless communication system and optical based wired system. In the radio based wireless communication, the location of AP(Access Point) Enclosure and Antenna shall be optimized for the guaranteed communication channel between wayside and trains either open aired or tunnelled area. This study is introducing the way of determinating optimized positioning the radio based wireless communication equipment in Bundang Line. At this moment, this CBTC project for the KNR's (Korea National Railway) intelligent train control system are in installment phase therefore the simulation data can show only from lab equipment. After the phase I testing, more detailed data can be collected and advanced paper will be issued in a short time.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1023-1026
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• 2007

CBTC (Communication Based Train Control) is a railroad system, using wireless communication for data transmission between on-board units and ground units, that makes ground computer periodically collect position and speed data from each train and transmits the preceding train's distance data up to speed limit point so as to make on-board control unit control the optimum train speed. Due to the fact that wireless communication system for train control employs only limited frequency band and output frequency, a number of ground communication units should be installed at track-side; also a running train should carry out Handover function which maintains the communication by accessing a new communication channel of the adjacent on-board communication units in accordance with the output of received radio wave. Especially CBTC is largely dependent on Handoff function between ground communication units. Therefore, this paper provides the method of identification of hazard between ground communication units and on board units.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.8
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• pp.875-882
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• 2015

Recently, An introduction of communication based train control system both into greenfield and brownfield of urban transit network has been actively reviewed. However, since a number of line sections and rolling stock depots tends to be constructed based on track circuit for various reasons, necessity of inter-operation between two distinct train control system (CBTC, ATC) increases. Therefore, we propose a design of on-board signalling device that allows inter-operation of CBTC and ATC lines and a method to secure safe connection between these two lines without derailing point machine.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2755-2761
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• 2011

The purpose of this study was to analyze and improve the communication interferences in the wireless communication equipments of the CBTC applied to a model intelligence train control system. So far, train positions have been traced by the conventional fixed blocking system to control the operation of the trains, but the new CBTC system uses the on-ground location to transmit the train positions wirelessly to the ground control center continuously, so being more vulnerable to communication interferences. Although the researcher analyzed and improved such interferences in the communication equipments of the CBTC system, there remain more rooms for its improvement.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1138-1144
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• 2008

To study the feasibility of applying wireless communication technology to the control of train for the effective control of train and for the reduction of cost and time to construct the necessary infra structure, we investigate into the application of the existing commercial WCDMA network to CBTC (communication-based train control) to grasp the obstacles and propose the solutions to circumvent them. The obstacles can be categorized into the hand-off problem, the interference problem near the stations, and the problem of radio shadow areas. We propose, as solutions, the cell overlap method and multi-terminal approach for the hand-off problem, the cell sectoring method for the interference problem, and establishment of new base stations along the railroad both to provide the wireless train control and communication service to the customers on the train which was otherwise impossible because of the shadowing effect.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1454-1460
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• 2006

This paper assesses communication performance using a roaming simulator when roaming occurs between onboard and ground wireless communication devices for communication based train control system (CBTC). Generally, CBTC is defined as the system regularly collecting location and speed data from each train, transmitting distance information to a train, and optimizing train speed according to train performance. When a train is moving, roaming is also performed to continuously transmit and receive train control information between the ground controller and the train. To operate CBTC, packet loss rate should be less than 1%, roaming time less than 100ms during roaming. We developed a roaming simulator to check communication performance before installing ground and onboard equipments on actual wireless sections. The roaming simulator to be introduced in this paper is for roaming simulation before conducting CBTC field test, which is the project to develop Urban Rail Signaling System Standards, being conducted in KRRI. The simulation consists of one onboard wireless communication device and three ground wireless communication devices, and the roaming simulator estimate packet loss rate occurring during roaming process of the two devices. Therefore, if you use the roaming simulator before the field test, you can predict various problems to occur in actual environment and reduce time, cost and people necessary to resolve these problems.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1321-1326
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• 2008

According to the conventional train control system, the area of each train is detected by plural track circuits located in a constant distance on railway lines in order to control a distance between trains. The conventional train control system has the difficulty in making use of the substructure thoroughly and transmitting enormous amount of information. To solve those problems, the wireless CBTC system has been a global issue. To apply wireless CBTC system to train system, the following two requirements are preferentially necessary: (1) Dualizing wireless CBTC system to control trains ceaselessly in a system accident, (2) Improving dependency of transmitted information for location and velocity to protect collision and derailment of lightweight trains in advance.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2292-2299
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• 2011

The CBTC(Communication Based Train Control) system, a recent train control system, is a wireless communication based train control system that is operated in the moving block system control by tracking trains in real time. In additioin, the system helps to increase the volume of traffic by shortening driving headways through controlling moving block system control. Furthermore, driverless modes are performed by controlling ATP(Automatic Train Protection)/ATO(Automatic Train Operation). In this paper, controllable elements in ATO driverless train control system, affecting comfortable ride, will be analysed and applied to CBTC train control system that developed by POSCO ICT. Finally, the test results of improved comfortable ride will be showed by appling the developed system to the Gyeong-san light rail transit test track.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.1
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• pp.61-67
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• 2018

Automatic Train Stop (ATS) is a device that automatically stops or decelerates a train when the train exceeds the permitted speed limits or violates the signal regulations. The railway signaling system has been evolved to an automatic train control system (ATC), and is being developed into Distance-to-Go and Communication Based on Train Control (CBTC). In spite of that, the ATS system is currently being operated in Seoul Metro (line 1 and 2) and most of railway lines in Korea as well as overseas. In this study, we presents the technical methodology to prevent human errors in order to secure the safety in operation of the ATS system.