• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.8
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• pp.1256-1261
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• 2015

Along with the increase of railway catenary system operation speed to 400 km/h, there have been growing demands for good quality current collection systems that satisfy quality standards as well as criteria for safe working. Retaining uniform elasticity tension of contact wires is essential in maintaining high quality contact between pantograph and OCL (Overhead Contact Line) of current collection systems in high speed railways. Therefore, the tension of contact wire must be kept within tight tolerance limits in both working conditions and adverse weather conditions of catenary system. In accordance with these conditions, this paper presents a real time monitoring system for the tensioning device of the newly installed catenary system on the special route of Honam high speed line for 400 km/h operation. For the verification of the true value of tension of contact wires, we have developed ring-type tensioning sensors which were installed on supporting points of mast which compose the catenary system. According to the field test performed on the Honam high speed line catenary system, variation of tension was measured accurately in real-time.

• Transactions on Electrical and Electronic Materials
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• v.7 no.5
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• pp.247-251
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• 2006

The traction DC feeder cable is one of the key devices for the safety operation of subway system, but for low voltage DC feeder cable (<3000 V) for subway, little attention has been paid by investigators on its online monitoring technology. With an introduction of cable laying and operation environment for the cable, this paper investigated the on-line monitoring technology of 1500 V DC feeder cable of subway. Firstly, in the text, the fault model of 1500 V DC cable was proposed based on the analysis of the fault type of the DC feeder cable, and then put forward synthetically on-line monitoring discharge signal and DC leakage current signal to assess DC feeder cable insulating state. The results of laboratory experiment prove that the proposed methods are feasible and can be implemented on-line monitor on DC feeder cable of subway.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.666-670
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• 2011

ATS(Automatic Train Stop)s are is effected by track environment, signal distance and train braking distance. So onboard signaling systems such as ATP(Automatic Train Protection) are installed on conventional lines by some train operation companies. With the mixed signalling, the onboard signaling system is overlaid on a conventional line with ATS, it is possible to run the line with conventional trains and ATP trains and to use the advantages of ATP(higher speed or more trains on the line). This paper includes guidelines a mixed signalling(ETCS and ATS) system architecture, operation concepts and infill balise installation.

• Journal of the Korean Society for Railway
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• v.8 no.6 s.31
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• pp.507-512
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• 2005

Railroad transportation system has experienced major changes due to KTX introduction. Kyungbu corridor especially Seoul to Cheonan has line capacity problem and its solution has been a primary concern to researchers and policy decision makers. This study explored pattern of train operation between Seoul and Cheonan after the introduction of KTX in 2004. Both the number of trains and available seat capacity per day have increased but maximum number of trains per specific hour has not been changed much. Demand for train shows that if concentrated in a specific time, so number of trains during the peak hour should be increased. But, it is difficult ? 새 line capacity, so increasing seat capacity per train might be an option. An increase in an avaliable sear should be considered the characteristics of each train lines.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1515-1521
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• 2007

In this paper, a unified regenerative inverter system for railway with DC line voltage simulator is proposed. In order to determine the operation characteristics of the regenerative inverter, the DC line voltage simulator is proposed. The DC line voltage simulator, which is based on the AC-DC PWM converter, varies the DC voltage according to the fluctuating voltage which is measured in the actual DC line. The suitable operating point of the regenerative inverter can be estimated from the simulation result. The regenerative inverter operates two modes. When the DC line voltage exceed the operating point, already set up, it works as regenerative inverter to return the excessive power of DC line to the grid. When the DC line voltage is under the operating point, it works as active power filter to compensate harmonic currents. In this paper, the control algorithm of the DC line voltage simulator and that of the regenerative inverter is proposed.

• 전기의세계
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• v.26 no.3
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• pp.84-91
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• 1977

A modified version of algorithm and computer program is proposed to improve the currently available contingency analysis methode for the security control of power system. The underlying principle is based upon the reasonable modification of the current methods suggested by Stagg, Tinny, Alsac, and Stott in consideration of speed, aceuracy, reliability and convergency characteristics. The algorithm and program are desirgned especially for On-Line operation, although Off-Line applications are readily available. Several case studies on the Koren Power Company's 48-bus, 91-line system have shown that the method proposed is efficiently powerful in a sense of practical applicability.

• International Journal of Contents
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• v.3 no.3
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• pp.38-42
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• 2007

In this paper, we propose a new storage system architecture called as U-Storage (ubiquitous storage system). U-Storage allows a user to access an on-line storage with any type of information devices that are able to connect to internet. The on-line storage is virtualized to the user's information devices as a local hard disk or a memory card by our U-Storage. With devices supporting U-Storage, users can read and write their data anytime and anywhere without downloading and uploading operation.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.10
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• pp.360-366
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• 1983

In this paper, operation cost of the system is calculated by the probabilistic simulation method. And it is proved that only 20 iterative simulations are enough to get the result obtain by the Monte Carlo simulation method which requires more than 1000 iterative simulations. In the probabilistic simulation method we use the ranking of line contingency which is derived from the line countingency selection algorithm proposed in (2). In using this method the nature of the sparsity of the power system is used.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7C
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• pp.723-727
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• 2002

In this paper a new remote control system for operating indoor gas(LPG) range safely based on PLM(Power Line Modem) and telephone is developed because it would make disasters of properties and lives by user's carelessness or worker's bad installation, etc. The system includes the following elements: a telephone line interface system for user to call from the outdoors to the indoors, a communication system using the power line as a communication media, a system of cutting off gas and a alarm system.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1412-1417
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• 2011

Safety is soaring up as a core value in accordance with the recent improvement of operating speed & incidents. rolling stock is a kind of system which works together with several components. one component has an effect on the sub-system, which can cause to the train safety operation, therefore reliability management of the major components of rolling stock is a kind of solution to the safety operation of train, but realistically maintenance in korea performed based on period rather than TBO of major components, but Japan does new maintenance system based on the major components, which optimizes maintenance tasks. actually Japan can apply to new maintenance system because they are ready in planning step but in this study, making a reliability data of major components and review the adaptability of new maintenance system to the rolling stock operating in Ansan line.