• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.11
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• pp.1905-1909
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• 2008

As catenary supply electric power directly to the railway system, it is very important to prevent an accident of a catenary for appropriate train operations. This paper analyzed the outage data for British catenary safety analysis report and Korean data to compare the reliability of the railway systems. The analyzed data were applied to Fault Tree Analysis(FTA) algorithm to calculate the reliability indices of a railway system. Failure rate of an electric railway system through FTA were calculated for each element and the entire railway system. The reliability indices can be used to determine the eqipment to be replaced for the entire system reliability improvement.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.273-286
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• 2017

We develop an inspection method for bearing faults with a rapid change in the rotation speed and present indexes for the pass/fail inspection. At the end of line, impulse noises generated by the operation of machines and conveyors may distort the inspection results. In this paper, we present robust inspection indexes for bearing faults under impulse noises, by taking into account fault signals having pulse train. Using logistic regression, we optimize the pass/fail criterion for each index and evaluate the performance of the inspection indexes based on the total error rate.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.10a
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• pp.325-329
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• 1992

The development of automatic production system have required intelligent diagnostic and monitoring function to repair system failure and reduce production loss by the failure. In order to perform accurate functions of intelligent system, inference about total system failure and fault analysis due to each mechanical component failures are required. Also the solution about repair and maintenance can be suggested from these analysis results. Generally, bearing is a essential mechanical component in the machinery. The bearing failure is caused by lubricant system failure, metallurgical defficiency, mechanical condition(vibration overloading misalignment), environmental effect. This study described roller bearing fault train due to stress variation and metallurgical defficiency from lubricant failure by using FTA.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.12
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• pp.667-673
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• 2006

Programmable electronic interlocking system plays key role in railway operation and is closely related to railway accidents, in which the programmable electronic controller of interlocking system may become sources. Redundant digital controllers are adopted as the interlocking controllers to prevent the accidents from the controllers being out of order. The redundant digital controllers being fault tolerant are realized through dual or triplex controllers. In this paper, we calculated safety and availability of the redundant digital controllers using Markov models, demonstrated key part to determine the availability ana the safety.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.518-523
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• 2008

Using network communication, KTX OBCS is KTX's core device which inspects operation status of various electric equipments and supports driving command, train control, train's maintenance, train crew's driving. Since this device is manufactured as specialized system, being dependent on TGV manufacture specification and France's high speed train operation method, actual technic transfer is difficult. Therefore, there are many difficulties, since most of interface signals are connected with OBCS when function improvement, maintenance, various electric equipments(propulsion control device, auxiliary power supply device, door control device etc.) are replaced with localized ones, which are required in operational view after introduction of KTX. Ergo, this study would like to contribute to function improvement and maintenance's efficiency, furthermore to realize technical independence, escaping from dependency of developed foreign technology in high speed train and electric equipments, through KTX OBCS' function analysis and mutual interface information analysis with peripheral device(driver console, PID system, fault display device, various electric equipments).

• Journal of Mechanical Science and Technology
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• v.16 no.12
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• pp.1604-1612
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• 2002

Rollers in the continuous process systems are ones of key components that determine the quality of web products. The condition of rollers (e.g. eccentricity, runout) should be consistently monitored in order to maintain the process conditions (e.g. tension, edge position) within a required specification. In this paper, a new diagnosis algorithm is suggested to detect the defective rollers based on the frequency analysis of web tension signals. The kernel of this technique is to use the characteristic features (RMS, Peak value, Power spectral density) of tension signals which allow the identification of the faulty rollers and the diagnosis of the degree of fault in the rollers. The characteristic features could be used to train an artificial neural network which could classify roller conditions into three groups (normal, warning, and faulty conditions) The simulation and experimental results showed that the suggested diagnosis algorithm can be successfully used to identify the defective rollers as well as to diagnose the degree of the defect of those rollers.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.444-446
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• 1994

This paper describes the design of a digital multifunction controller for the intelligent high voltage customer switchboard and proposes a relaying algorithm for high impedance faults using back-propagation neural network. The hardware design uses the three microprocessors and global memory architecture to achive real time operation and control 4 feeders. The controller uses a 64-point radix-4 DIF FFT algorithm to measure the harmonic and relay parameters. Synthesized fault current waveforms are used to train and test the back - propagation network.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.459-466
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• 2001

As the Public use part of the railway and the road, the railway crossing is important to work properly by two transportation means. Also, It is important to provide the good face of friction on the railway crossing in aspect of protecting the railway crossing accident. Lately, the material of railway crossing panel is the wood, the asphalt, and the steel. As they have a various fault, it was studied to analyze the structural action of the new material, rubber panel. This paper analyzed eigenvalue, stress and displacement by truck passing weight, thermal stress and train moving weight, using the FEM model.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.476-483
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• 2000

Like other vehicles, the suspension elements of railway rolling stock have influence on running stability and ride quality. Thus, faults detection for suspension elements is important to prevent an accidents of train and to ensure safety against derailment. This study was started to grasp the feasibility of diagnostic method for the suspension elements of bogie without disassembling. Through several tests by running test rig, we found that fault detection for suspension elements was possible. Here, we describe some results.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.498-508
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• 2008

TECA(Terminal Cabin) has train information, fault display, maintenance function and training function for driver, as sub-device of Seoul-Pusan Express train's on-board computerized device. Concerning KTX train's driving, signal driving is required for high speed driving, and it is true that we have difficulty in troubleshooting and acquisition of basic information through long train and one-man driving. Therefore, rapid and correct processing about various information and TECA device for maintenance are indispensable for its utilization. But there is not study example in hardware, maintenance about this device and device development according to new requirements. Therefore, this study will help understanding of driver assistance terminal device's maintenance performance development, describing TECA's basic functions necessary for device development and its requirements. Accordingly, I suppose that this thesis will be utilized to complete specification, necessary for new driver assistance terminal device development.