• 제어로봇시스템학회논문지
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• 제22권2호
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• pp.162-169
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• 2016

Gyeong-bu railway line in Korea between Seoul and Cheon-an was built as two double tracks. A four-display signaling system, only for the metro line, was installed on the second double track so KTX and conventional trains can only operate on the first double track. This study suggests a method to allow KTX and conventional trains operated on the five-display signaling system to respond to accidents and track defects on the second double-track under the four-display signal system by means of problem analysis, calculation of breaking distances for KTX and conventional trains at each break mode, and improvement of the ATS system.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권6호
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• pp.298-306
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• 2002

We performed an safety evaluation on constructing of a common grounding system for electrical railway in view of its efficacy and technical fit. In order to compare the conventional grounding method, which has been individually conducted, with the common grounding with all ground wires connected in common to the counterpoise buried below the surface of the earth in parallel with rail, we set up scenarios with several cases of fault and load conditions in Chungbuk railway sections with the common grounding system. Based on models for railway conductors including the grounded system, line Parameters of railway power system are computed. The circuit model for power system with up and down lines, auto-transformers and railway substations is used to compute impedances of counterpoise and substation ground net. For each scenario with faults and operation conditions of railway, the induced potentials on signal and communication lines are also computed. It is shown that the common grounding for Chungbuk railway is superior experimentally to the conventional method in three respects: (1) the lower rail potentials during operation of railway in line, (2) the lower rail potentials for short-circuit faults between catenary and rail, and (3) the lower stress voltages on signal and communication lines for short-circuit or ground faults. The analysis results confirm that the grounding system for electric railway is required to be built by the common grounding and be evaluated on its safety in design.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.856-862
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• 2006

In railway signalling system, there are several kinds of signal system such as signals, signs, marker. The signals allows train to go or not, the signs permit to communicate between railway men, and the marks indicate status of railway lines. In KNR, the application of the signal systems are defined in railway operational regulations, operational related regulation, Operation safety critical system manipulation manual, and so on. In this paper, we extracted regulations for signalling system operation from related regulations, reviewed compatibility and contradiction for signalling system operations. We tried to check logical integrity of informal signalling operation regulation using formal method.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.126-132
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• 2003

Recently with the rapid development in mobile communication, the mobile phone are utilized in many fields of railway system within country and abroad and its use tends to increase continuously. In the railway system, the applicable realm is spreaded to the fields of railway signal communication, railway operating, track maintenance, reservation and information service, also its role is expected to increase. In this thesis, we are surveying the usage application of home and abroad mobile phone in railway system. Studying the present condition of mobile communication in railway system, we are viewing the application plan and the direction of development.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.647-652
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• 2008

Railway signal system has been more complex, larger and required high reliability. So, maintenance by experience must be changed to optimize maintenance program or introduced systematic method for estabilish new maintenance program. In this paper, we introduced the maintenance period decision method which are Age based method and Block replacement method based on the failure distribution for the equipment. So, we allocated optimum maintenacne period for the railway signal equipment using block replacement method.

• 전기학회논문지
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• 제67권11호
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• pp.1530-1535
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• 2018

In this paper, A technique for detecting contact loss at the input power of a railway vehicle has been studied when the contact loss occurs in the feed system. The impedance of the actual railway line was applied to the modeling of the feed system, and modeling was performed based on the performance of the electric railway vehicle. The input voltage and current of the railway vehicle through modeling were analyzed by applying TEO and STFT signal processing technique.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 춘계학술대회 논문집
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• pp.473-480
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• 2002

In this paper, it was proposed that hazard analysis and risk assessment about railway signal systems using FTA(Fault Tree Analysis) and ETA(Event Tree Analysis) one of the reliability analysis methods executed and output value based on the hazard baseline of CENELEC and EC 61508 producted, and also the SIL(Safety Integrity Level)/THR(Tolerable Hazard Rate) about the system set. On the basis of this principle, more systematic standardizations are required to operate railway system and in the future, we hope that safety and reliability of signal equipment will be better improved.

• 한국안전학회지
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• 제31권3호
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• pp.28-33
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• 2016

Since defects in the wheels of railway vehicles, which occur due to wears with the rail, cause serious damage to the running device, the diagnostic monitoring system for condition-based maintenance is required to secure the driving safety. In this paper, we studied to apply a useful Cepstrum analysis to detect periodic structure in spectrum among the vibration signal processing techniques for the fault diagnosis of a rotating body such as wheel. In order to analyze in variations of train velocity, the Cepstrum analysis was performed after a domain change of the vibration signal from time domain to rotation angle domain. When domains change, it is important to use a interpolation for a uniform interval of the rotation angle. Finally, the Cepstrum analysis for wheel flat detection was verified by using the vibration signal including the disturbance resulting from the rail irregularities and the vibration of bogie components.

• 전기학회논문지
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• 제61권7호
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• pp.1056-1060
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• 2012

Online monitoring system is becoming an essential element of railway traction system for utilized to condition based malignance management and various techniques currently employed in railway traction system. Among the various techniques, it is efficient to detect partial discharge signals by electromagnetic wave detection in order to detect insulation fault of rectifier. Although VHF (Very High Frequency), UHF (Ultra High Frequency) sensors were adopted to detect partial discharge of power facilities, due to characteristics of urban railway, excessive noise occurs from 500 MHz to 1.5 GHz on UHF bandwidth. In this paper a new measurement system able to monitoring the conditions of power facilities on DC substation in metro was studied and set up. The system uses UHF sensors to measure the partial discharge of the rectifier due to electric faulting and dielectric breakdown. Comparison and estimation for performance of SHF sensor which had devised to detect partial discharge signal of urban railway rectifier has conducted. In order to estimate performance of SHF sensor, we have compared the sensor with existing UHF sensor on sensitivity upon frequency bandwidth generated by pulse generator, and also we have verified performance of the SHF sensor by detection results of partial discharge signal from urban railway rectifier.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.836-842
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• 2005

This paper presents a power supply of railway signal system using a Z-source inverter. The Z-source inverter overcomes the conceptual and theoretical barriers and limitations of the tradition voltage-source inverter and current-source inverter and provides novel power conversion concept. The Z-source inverter is a Buck-Boost inverter that has a wide range of obtainable voltage.