• 한국정보통신설비학회:학술대회논문집
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• 2002.08a
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• pp.79-81
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• 2002

초고속 인터넷 서비스는 정보화 시대에 살고 있는 우리에게 없어서는 안 되는 존재가 되고 있다. 이에 맞추어 KT는 기존의 가입자 동선 케이블을 이용하여 초고속 인터넷 서비스를 제공하기 위해 서비스 속도 향상과 음영지역 해소를 위한 다양한 해결방안을 모색하여왔다. 그 결과로써. 옥외 통신장비를 수용하기 위한 방안으로 광전송장비를 지하에 수용할 수 있는 CEV의 필요성이 대두되었으며 CEV의 개발이 완료되는 시점이 다가옴에 따라 KT는 언제 어디서든 고품질의 인터넷 서비스를 제공할 수 있는 인프라를 갖추게 되었다.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.298-302
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• 2004

In this paper, AC electric vehicle propulsion system(Converter/Inverter) using high power semiconductor, UM(Intelligent Power module) is proposed. 2-Parallel operation of two PWM converter is adopted for increasing capacity of system and the VVVF inverter control is used a mixed control algorithm, where the vector control strategy at low speed region and slip-frequency control strategy at high speed region. The proposed propulsion system is verified by experimental results with a 1,350kW converter and 1,100kVA inverter with four 210kW traction motors.

• International Journal of Railway
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• v.5 no.3
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• pp.124-128
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• 2012

The ESS(energy storage system, here after) for a DC 1500V was developed in 2009. A ESS was installed on the track of Daejeon HRT in 2010. The advantage of the ESS is that it can save the energy and plus stable the catenary voltage. This paper presents the energy saved by the ESS in Daedong substation. When the ESS is on/off, the field tests are performed.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.8
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• pp.863-869
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• 2015

This study analyzed the offshore plant industry and related regulations such as ISO, IEC, and Norsok Standards to develop an integrated network management system (INMS) capable of both on-site and remote management and configuration of IP-based network equipment in offshore plants. The INMS was designed based on actual specifications and POS plans, and a plan of management was verified through an offshore plant engineering company. Various modules such as PAGA interface modules, CCTV, IP-PBX, and HF-radio communication modules were developed for system implementation. Protocol and data design and screen design were followed by framework development and introduction of the automatic satellite communication function.

• Broadcasting and Media Magazine
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• v.11 no.1
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• pp.78-85
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• 2006

Cognitive radio is a paradigm for wireless communication in which either network of wireless node itself changes particular transmission or reception parameters to execute its tasks efficiently without interfering with the licensed users. This paper represents a performance of the cognitive radio technology on dual polarized MIMO system using six-port receiver. Six-port technology is well known direct conversion receiver. In this paper, a six-port phase discriminator based polarization signal separation is shown. That is, the SER(Symbol Error Rate) performance is improved using polarization separator and simple receiver architecture is proposed applying six-port receiver. The six-port technology has priority to adapt changeable frequency system and variable environments for cognitive radio. In general, dual polarized MIMO system has good capacity and quality using polarization separator [1].

• International Journal of Railway
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• v.6 no.2
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• pp.64-68
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• 2013

In recent years, the speed of a train has been recognized as one of the important factors to determine the competitiveness as a mean of transportation. In line with this, infrastructure improvements and enhancements are being made with increases in the speed of train. Accordingly, there is a need to establish plans for infrastructure improvements through a comprehensive analysis of signals, track/civil engineering, catenary and environment, etc. to improve the speed of a train of high-speed train service sections in Korea. This study proposes improvement plans for catenary systems by investigating the possibility of improvements through performance analysis of catenary equipment by speed increase based on the analysis on catenary systems in Gyeongbu high-speed line, and analysis the applicability of catenary improvements and economic feasibility.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.164-166
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• 1998

This paper presents the results of the measured pressure-rise and the analyzed results of the cold gas flow-field in a 72.5kV 20kA gas circuit breaker for the electrical railway system. The analysis of cold gas flow field and the calculation of electric field strength have been performed in 3 types of interrupters and the low current interruption capability has been estimated for each of the gas circuit breaker considering the opening speed, the nozzle shape and the stroke length.

• Proceedings of the KIEE Conference
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• summer
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• pp.1334-1336
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• 2004

The existing problems of the Electro-Magnetic Suspension system such as air-gap disturbance, mass variation and actuator/sensor failure are described in amore specific manner. These problem can not be solved by conventional state-feedback and output-feedback control. Extended Kalman Filter is to linearize about a trajectory that is continually updated with the state estimates resulting from the measurements. In this paper, first, the physical properties of the EMS system are described. second, Extended Kalman Filer designed as form appliable EMS system. It is shown that state estimation performance can be obtained with the use of Extended Kalman filter, and that results from simulation, stability analyze.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2028-2030
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• 2003

This paper describes the results of reliability prediction analysis of control rod control system, which is being developed as part of KNICS project. The results of reliability prediction indicate MTBF(Mean Time Between Failure) of cards for control rod control system. A purpose of reliability prediction is to evaluate MTBF of cards, identify the design drawbacks of cards, and propose design improvement to a designer to help design the more reliable control rod control system. This reliability prediction analysis used the the part count and part stress method in the basis of MIL-HDBK-217F.

• Journal of Astronomy and Space Sciences
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• v.26 no.2
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• pp.267-278
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• 2009

Automation of the key flight dynamics operations for the geostationary orbit satellite mission is analyzed and designed. The automation includes satellite orbit determination, orbit prediction, event prediction, and fuel accounting. An object-oriented analysis and design methodology is used for design of the automation system. Automation scenarios are investigated first and then the scenarios are allocated to use cases. Sequences of the use cases are diagramed. Then software components and graphical user interfaces are designed for automation. The automation will be applied to the Communication, Ocean, and Meteorology Satellite (COMS) flight dynamics system for daily routine operations.