• Proceedings of the KSR Conference
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• 2007.11a
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• pp.129-134
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• 2007

When constructing a high-speed railroad, the reduction of the distance between track centers and the width of track bed may bring about the effect of cost savings. When, however, considering the influence that the increase of wind pressure due to the change of the distance between track centers may have on the stability of train operation, extensive technical review and overall studies need to be performed before the distance between track centers is determined. Therefore, in this study, the impact that the increase in wind pressure due to the change of aerodynamic phenomena with the change of the distance between track centers may have on two trains passing by each other was predicted, and the stability of train operation was analyzed in order to review the distance between track centers suitable to Honam HSR trains. In this study, we estimated the aerodynamical effects by the results of the real train experiments.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1050-1051
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• 2008

도로에서 전력 통신용으로 쓰이는 전주나 전선의 설치로 인한 도로 점용은 보행자의 안전과 원활한 통행로 확보에 문제로 지적되었는데, 최근 도시는 지상의 설치물을 지하로 매설하여 깨끗한 가로 환경을 조성하는 추세이다. 반면 국도 ITS 사업은 지상에 여러 종류의 장치, 전력선, 통신선을 구성하면서 도시 경관을 해치는 요인으로 지적받고 있다. 이에 통신 선로의 지중화를 통해 도시 경관 정비가 중요한 과제로 인식되고 있으나, 가공 선로보다 2배 이상의 설치비용이 더 필요하다. 일본의 경우, 1986년부터 2차례에 걸친 전선류 지중화 계획을 관련 성 청, 전력 통신사업자 등과 연계하여 Cab System 방식으로 전선류 지중화를 추진하고 있는 실정이다. 본 논문은 우리나라에서 추진하는 국도 ITS에 적합한 광통신망의 지중화 방안을 제시한다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.367-368
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• 2015

최근에 인도와 유럽을 중심으로 기존의 AC 송전계통 중 일부를 DC 송전계통으로 대체하는 하이브리드형 송전방식에 대한 연구가 진행중이다. 따라서 본 연구는 기존에 연구되고 있는 하이브리드형 가공송전계통을 기반으로 지중송전계통을 포함한 하이브리드형 혼합송전계통이 향후 머지않아 국내에서 계획 및 건설될 것을 대비한 초기 연구로서 진행하였다. 본 논문의 관점은 하이브리드 혼합송전계통 중 지중송전계통구간에서 DC 선로가 AC선로로부터 얼마나 고조파 전압 및 전류 측면에서 영향을 받는가를 평가하고, 이를 근거로 DC 케이블의 배열을 선정하고자 한다. 또한 DC 케이블 배열 선정을 위해 가능성이 있는 여러 개의 CASE별로 구분하고, 가장 타당한다고 평가되는 배열을 제안하고자한다. 본 연구에서 계통 모델링 및 해석은 EMTP를 이용하였다.

• IE interfaces
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• v.9 no.3
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• pp.101-109
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• 1996

가입자선로는 통신망 이용자가 단말장치를 이용하여 통신서비스를 제공받는 부분으로 통신시설투자의 상당한 비를 차지하고 있다. 그러나 가입자선로는 그 규모의 방대함과 구조의 복잡성 및 다양성 동으로 신기술의 도입이 늦으며 변화의 정도가 매운 느린 분야로, 멀티미디어 서비스 및 인터넷 등 신규 서비스의 태동과 치열해지는 통신시장의 경쟁 상황에서 전체 네트워크의 병목이 되고 있어, 기술 및 운용상의 측면에서 뒤늦게 주목 받는 분야가 되었다. 본 고에서는 통신망의 근간이 되는 가입자선로의 구성 및 역할에 대하여 살펴보고 급변하는 정보통신 환경 속에서의 가입자선로의 위치를 신규서비스 및 가입자선로 기술 발달의 측면에서 서술하고, 초고속통신망 구추계획의 핵심이 되고 있는 광가입자선로 배선기법을 중심으로 한 가입자선로망 설계 및 추후 연구방향에 대하여 논하고자 한다.

• Proceedings of the KAIS Fall Conference
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• 2006.11a
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• pp.73-75
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• 2006

본 논문은 현재 운행 하고 있는 과천선의 도시철도를 중심으로 충돌 속도별 인명 상해치를 연구 하였으며 더 나아가 에어쿠션의 유무에 따른 인명 상해치를 저감시켜 많은 인명을 구조하기 위한 에어쿠션의 개념 설계를 하였다. 그 결과 에어쿠션 장착에 따른 높은 인명 구조 효과가 있음을 제시 하였으며 개념 설계를 기초로 하여 시험을 수반한 해석을 실시한다면 선로 침입자를 위한 도치철도 구조장치를 개발 할 수 있을 것이다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.11
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• pp.1663-1668
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• 1993

An X-band contiguous band diplexer is realized by using asymmetrical coupled microstrip lines. The design is based on the singly terminated low pass prototype filter and optimized by using SuperCompack. The designed channel 1 and channel 2 bandwidth is 22%, and 18% respectively, where the center frequency is 9,11 GHz. The measured results of the fabricated diplexer are in good agreement with the designed ones, but the measured insertion loss is slightly highier(0.5dB) than those of the designed value.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.7
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• pp.657-666
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• 2002

In this paper, a new broadband phase shifter to adjust the slope of dispersive phase characteristic for frequency of transmission network was proposed. The new fundamental network consists of a fixed main line with a length of λ/2 at the center frequency and two double stubs, each with a length of λ/8 at the center frequency, which are open and shorted, respectively, and which are shunted at the edge points of the main line. Characteristic impedances of the main line and two parallel double stubs are adjusted to produce a minimum phase error and to obtain an input and output match at the desired phase shift. Especially, the proposed structure is especially suitable for a broadband phase shifter with large phase shifts more than 90$^{\circ}$, and it is operated in the octave bandwidth. To verify the usefulness of a new broadband phase shifter, each 45$^{\circ}$-, 90$^{\circ}$-, 180$^{\circ}$-bit phase shifter and 3-bit phase shifter(45$^{\circ}$-phase step), which is cascaded in series, operated at the center frequency 3 GHz were designed, fabricated and experimented. The measured results were in very close agreement with the corresponding simulation results over the bandwidth of I/O impedance match and phase error for each phase shift.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.880-887
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• 2020

This study was conducted to investigate the running stability of a high-speed train operated in a tunnel and an open field when external forces such as wind pressure and train crossings were applied to the vehicle. With no external force, the running stability at 400 km/h was examined, and the wheel weight reduction ratio, lateral pressure of the axles, and derailment coefficient satisfied the criteria of the technical standards for a high-speed train. When the distance between the centers of the tracks is 4.6 m, the external force caused by train crossing slightly affects the lateral acceleration of the vehicle but does not significantly affect the wheel weight reduction rate, lateral pressure, and derailment coefficient in a tunnel and open filed. When the distance is 4.6~5.0 m, the wheel weight reduction ratio, lateral pressure, and derailment coefficient satisfy the criteria with 20 m/s wind. When the wind speed was 30 m/s, the derailment coefficient satisfied the criteria, and the other variables exceeded them. It is predicted that a high-speed train can be operated safely at 400 km/h with wind speed of up to 20 m/s, and it should be slowed down at a wind speed of 30 m/s.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5513-5521
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• 2015

There is an operational efficiency problem about wayside equipment applied to the domestic low-density branch as the equipment has been installed and operated similarly in the mainline. On-board oriented train control system, which has been developed for train safety and operation efficiency, ensures safe train operation without expensive ground control signal devices. Such system consists of on-board control system, wayside control system, and local control system. In this paper, the details of tests such as suitability test, communication test, and interface test are described by installing the on-board control system and wayside control system in field. Installation tests include checking power, voltage, cable connection, LED status, etc. Field applicability of the developed system is also verified through the dynamic operation tests with diverse scenarios, which are performed on the virtual line similar to the real environment including switch machine and level crossing gate. Dynamic operation tests were conducted for total 7 scenarios, and several tests were repeated for each scenario. The elapsed time for each operation was computed by analyzing main process log, and we could check that each operation was accomplished within several seconds. Furthermore, the developed system was verified through field test with an accredited institute, and testing certificates were issued.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1261-1263
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• 2002

In the aspect of economy and safety, it is essential to the decision of H-beam suitable for the condition of environment, installation, track etc. This paper presents a development of automatic design program to decide the size of H-beam according to the input condition.