• Journal of the Korean Society for Railway
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• v.9 no.3 s.34
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• pp.257-263
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• 2006

This paper presents an optimization approach to the configuration of train radio communication network for CBTC. The target specifications of CBTC communication systems are derived from technical requirements for CBTC. The proposed communication system has a ring-topology backbone communication network between stations and a radio network based on IEEE 802.11b wireless tan between trains and wayside devices. The proposed method has been applied to the standardization of the signalling system of urban transits.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.559-571
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• 2008

Platform Screen Door(PSD) has been installed and operated at seoul subway line $1\sim4$ in the manual train operation mode(ATS/ATC) by SeoulMetro since 2005. SeoulMetro uses the wireless (RF) communication system and the train door detection system for the link between the train and PSD doors opening/closing motion in the manual train operation mode. For the convenience and safety of passengers, the train doors and the PSD doors opening/closing shall be synchronized as much as possible. In ATO(Automatic Train Operation) mode which provides the interface between train control system and PSD system, ATO signaling system makes the train doors and PSD doors open/close command signals systematically, so PSD doors can be opened/closed almost simultaneously with the train doors. But, in the manual train control(ATS/ATC) mode, PSD system needs to detect the train doors open/close operation and make PSD open/close command signals to actuate PSD doors. These PSD open/close commanding process cause time delay of PSD doors opening/closing motion in response to the train doors opening/closing motion. Sometimes the response delay time can be over 1 second, which is not proper to operate PSD, and need to be reduced This paper presents the reduction method of the PSD response delay time to improve the convenience and safety of passengers.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.10
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• pp.836-843
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• 2003

The automatic train control (ATC) system development project for the Automated Guideway Transit (AGT) system has high technical risk because the system is unmanned train control system using wireless technology which was unprecedented in train control industry of Korea. To overcome the technical risk during concept design phase of the ATC system development project, the integrated product team(IPT) carried out a reverse and reengineering process using a systems engineering design model. The generic systems engineering process is incorporated in the both reverse and reengineering process. As a result of the systems engineering effort, the IPT has built top layer systems engineering design model of the ATC subsystem. The purpose of this paper is to deliver the reverse and reengineering process which was used to develop the systems engineering design model of ATC system using a computer aided systems engineering tool. This study also shows that the model based reverse and reengineering process can reduce the technical risk by identifying the differences of requirement, functional and physical architecture between a reference system and a target system.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1044-1053
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• 2010

Transmitting correct train control information is important in a train control system which demands safety. The train control information includes the maximum speed of trains, position of preceding trains, incline of tracks and curve sections etc. A radio frequency-communication based train control system is influenced by the noise and interference because the train control information is transmitted by wireless between a on-board system and wayside system. The radio frequency-communication based train control system is a mobile communication system due to moving trains. The inter symbol interference(ISI) occurs by the multipath fading in the mobile ommunication system. As signal-to-noise ratio(SNR) is decreased by the ISI, the train control information is not received correctly. In case of tunnel section, numerous reflected waves exist. Therefore, the power density of receiver is decreased by difference among the received times, magnitudes, phases through the multipath. So, the train suddenly is stopped by the fail-safe operation in the train control system on account of decreasing the power density of receiver. In this paper, a line of sight model-(Additive White Gaussian noise(AWGN) channel), rayleigh and rician fading model are presented. Probability density functions which are related to the SNR are derived from the models. The fading phenomenon severely occurs as a result of analyzing the probability density functions. So, the space diversity method is used in order to reduce the fading effect and it is demonstrated by using Matlab program.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1838-1844
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• 2011

In this paper, the propulsion control of a high-speed maglev train is studied. Electromagnetic suspension is used to levitate the vehicle, and linear synchronous motors (LSM) are used for propulsion. In general, a low-speed maglev train uses a linear induction motor (LIM) for propulsion that is operated under 300[km/h] due to the power-collecting and end-effect problem of LIM. In case of the high-speed maglev train over 500[km/h], a linear synchronous motor (LSM) is more suitable than LIM because of a high-efficiency and high-output properties. An optical barcode positioning system is used to obtain the absolute position of the vehicle due to its wide working distance and ease of installation. However, because the vehicle is working completely contactless, the position measured on the vehicle has to be transmitted to the ground for propulsion control via wireless communication. For this purpose, Bluetooth is used and communication hardware is designed. A propulsion controller using a digital signal processor (DSP) in the ground receives the delayed position information, calculates the required currents, and controls the stator currents through inverters. The performance of the implemented propulsion control is analyzed with a small maglev train which was manufactured for experiments, and the applicability of the high-speed maglev train will be explored.

• International Journal of Railway
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• v.3 no.3
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• pp.106-112
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• 2010

Accidents at level crossing have large portion on train accidents, and causes economical loss by train delay and operational interruption. Various safety equipments are employed to reduce the accident at level crossing, but existing warning device, and crossing barrier are simple train-oriented protection equipments. In this paper, intelligent railway level crossing system is proposed to prevent and reduce accidents. For train driver's prompt action, image of level crossing and obstacle warning message are continuously provided to train driver through wireless communication in level crossing control zone. Obstacle warning messages, which are extracted by computer vision processing of captured image at level crossing, are recognized by train driver through message color, flickering and warning sound. It helps train driver to decide how to take an action. Meanwhile, for vehicle driver's attention, location and speed of approaching train are given to roadside equipments. We identified the effect of proposed system through test installation at Sea train and Airport level crossing of Yeong-dong line.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.4
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• pp.455-468
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• 2014

This paper presents seamless hand off implementation suggesting algorithm and Measuring /testing at the tunnel environment in order to derive the ideal value of wireless data transmission in RF-CBTC train control system modeled by Shinbundang Operation System. In addition, it proposes the ideal value(-57dB) for reducing the re-transmission or frequency interference rate and demonstrates frequency optimization which enables highly reliable data communication in Train control system using wireless communications. Based on these result, Shinbundang phase 2 plan to apply to this system.

• Journal of the Korean Society for Railway
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• v.16 no.6
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• pp.519-527
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• 2013

Mobile radio technologies have evolved in the railway industry offering seamless connectivity and various functionalities to improve railway service. Recently, advanced mobile communication technologies have enabled a new level of railway customer services with more efficient railway operation. Since the LTE mobile communication technology offers many benefits and better performance for new railway services, it is considered to be a strong candidate for the future railway mobile telecommunication. However, communication networks in the railway sector are critical for secure operation and have stringent requirements for reliability and safety. In this paper, we explain the requirements for the future railway mobile telecommunication. The LTE, which would be the future railway mobile technology, is analyzed against these requirements. We also introduce the current state of standardization for the future railway mobile telecommunication and its implementation plan.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.4
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• pp.473-477
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• 2013

The railway developed countries in Europe, Japan such as ERTMS Regional, FFB, COMBAT, it is the stage of development or testing the train control system for the signal system of branch interval of low density. Similar to the signal system used by the mainline and branch sections of low density domestic portions not suitable in terms of maintenance operational efficiency in accordance with the installation and operation in many cases. Therefore these low-density branch railway lines required that oriented train control system of wireless communication to improve the operation efficiency and line side equipment controlled on board the train. In this paper, We was published a route on setting is the operation of the new on-board oriented train control system for controlling a line converter of the train so that it is possible to improve the operational efficiency of the branch of the low density.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2705-2710
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• 2011

With the rapid development of information and communication technology, CBTC system based on the wireless communication is widely applied in the railway signal system recently. CBTC system has advantages of lower installation space and maintenance fee than existing systems and the increase of transportation capacity and improvement of operating efficiency etc. due to the short headway. Based on the continuous wireless data communication between onboard and wayside equipment, CBTC system not only locates the train and transmits the information required for the train control, but also implements the moving block function by calculating the brake curves continuously according to distance from the preceding train. CBTC system can use either inductive loop (IL-CBTC) or radio frequency transmissions (RF-CBTC). In this paper, we propose RF-CBTC system architecture based on the functional modules, in which the CAN bus network is applied for the interfaces between the modules.