• Proceedings of the KSR Conference
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• 2003.10b
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• pp.277-284
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• 2003

To meet demand for large-scale new personnel caused by active railway investment projects such as high-speed line construction, electrification and double-tracking of the existing lines, we KNR need to establish a subsidiary firm for each field instead of personnel augmentation. The establishment of subsidiaries is expected to solve the problem of the current outsourcing services, reduce costs and in the long term, improve the efficiency of railway business. In addition, we also suggest, as a pilot project, setting up Korean Freight Inspection Company in charge of conducting light and heavy maintenance for freight cars.

• Journal of information and communication convergence engineering
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• v.18 no.3
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• pp.201-206
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• 2020

This paper presents a new method for controlling the current of lighting LEDs without current sensors. This method can be used as backup against LED current sensor faults. LED lighting requires a circuit with a constant current in order to maintain the same brightness when the ambient temperature changes. Therefore, we propose a new current estimation method to provide backup in case of current sensor faults based on the calculation of the inductor current. In the fabricated circuit, the average current changes from 144.03 mA to 155.97 mA when the ambient temperature changes from 0℃ to 60℃. The application of this study can enable the fabrication of a driving IC for LEDs in the form of a single chip without sensing resistors. This is expected to reduce the complexity of the peripheral circuit and enable precise feedback control.

• Proceedings of the KIEE Conference
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• 2000.07e
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• pp.48-51
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• 2000

The purpose of this study is to find the way to reduce the electrostatics by interface activation substances added in the insulating oil with concentration[ppm]. As results, The streaming current, surface tension and viscosity of the samples added nonionic and hermaphrodic substances are decreased but the conductivity is increased at higher point than the 1[ppm](c.m.c.), the other side the same phenomena of the samples added cationic and anionic substances are discovered at the 10[ppm].

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.80-80
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• 2010

본 논문에서는 현재 사용되는 변압기의 절연유인 광유와 새롭게 대두되고 있는 식물유의 신유 상태일 때, 온도와 유동대전방지제(Benzotriazole)에 따른 대전경향을 비교, 분석함으로써 변화되는 조건이 절연유에 미치는 영향에 관해 연구하였다. 유동대전현상을 해석하기 용이한 직렬식 대전장치를 설계, 제작하여 실험한 결과 온도의 변화에서는 광유, 식물유 모두 60[$^{\circ}C$] 부근에서 최대치를 발생하였고 유동대전방지제의 첨가에 따라 유동대전은 광유, 식물유 모두 비슷한 경향으로 변화하였다.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1410-1412
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• 1998

The purpose of this study is to find the way to prevent the electrostatics from the interface of liquid and solid by adding interface active substances to the insulating oil with concentration. As results, The streaming current, surface tension, and viscosity decreased and conductivity increased at the higher point than the c.m.c. which resulted from, the adding of the interface active substances.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.538-543
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• 2000

The purpose of this study is to develope electrostatic separation system for recycling of mixed waste plastics. The electrostatic separation system is designed and investigated the separation efficiency for separating of mixed waste plastics. Electrostatic separation system consisted of a tribocharger, separator (two electrode), collector (5 tray) and controller (positive/negative high voltage power supply). The tribocharger is a fluidized bed using tribo-electrification mechanism between particles and particles. In experimental results, the tribocharger of the fluidized bed was more effective separation efficiency. It showed the purity of $85{\sim}99\;%$ and the recovery of $80{\sim}98\;%$ from the powder of mixed plastics such as LDPE, HDPE, PP, PS, PET and PVC. Especially, In the separation experiment of Polyvinylchloride(PVC) which generates hazardous hydrogen chloride gas in case of the combustion. its purity was over 99 % and recovery was over 95 %.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.11
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• pp.2059-2071
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• 1992

The characteristics of wave propagation along a catenary in rail electrification system depend on the boundary impedance, characteristic impedance of catenary, and the contact force of pantograph moving along the catenary. In this study, the wave propagation along catenary is studied with arbitrary boundary conditions and characteristic impedance of catenary. The reflection and transmission of waves through the boundaries of catenary and the propagation of waves along the catenary are found to be dependent on the wave length.

• Journal of the Korean Society for Railway
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• v.9 no.5 s.36
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• pp.582-587
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• 2006

Since Kyung-Bu High Speed Line has been introduced, a railway electrification has been proceeded rapidly. Therefore, in this study, a specification and application standard for an overhead catenary supporting thin walled steel pole using STKT590 material are proposed in order to improve an economical efficiency. To decide the specification, strength analysis, deflection analysis, deflection test and fracture test are performed. If the supporting structures using high strength materials such as STKT590 are installed, the advantages of cost by the materials price reduction and demand and supply are expected.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.628-635
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• 2000

The catenary system supported by the tunnel bracket which has been used uniquely in KNR was selected as the catenary inside narrow existing tunnel in the electrification of Kyeung-Bu Line for operation of Korea High Speed Train(KTX). It was demanded to judge the maximal operable speed of KTX in this catenary system to implement the planning. To do this, the tunnel bracket was firstly tested to obtain the characteristic data. The stiffness of this bracket are computed depending on the location which catenary installed on. Moreover, the catenary using tunnel bracket is modelled numerically respecting the bracket stiffness. Based on these, the dynamics between this catenary and KTX pantograph are simulated with the program developed by ourselves independently. The simulation result are evaluated according to the generally acceptable criteria. Consequently, the maximal operable speed of KTX in the catenary using KNR(Korean National Railroad) tunnel bracket is predicted and some items which are needed to be kept in the processing of implementation are drawn.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.229-235
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• 2007

The KTX, which have opened the revenue service in April 2004, is operating in Kyoung-Bu high-speed line and electrified conventional Ho-Nam line, and the more the electrification are enlarged, the more the requirement of operating of high speed train would be increased. In this paper, the result of test run and evaluation on the suitability of operating high speed train in electrified conventional line between Dae-jeon and East Dae-gu was reviewed. Evaluation and analysis was executed in specific categories, such as operation & running performance of the train considering vibration characteristics based on UIC 518, ride comfort and current collection, and response sensitivity of ATS device for signalling from track facility. The result of this running test was evaluated and considered as a good practice for revenue operation of high speed train in electrified conventional line between Dae-jeon and Dae-gu.