• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2808-2813
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• 2011

According to opening the domestic existing lines and High-Speed Lines(HSL) depending on each section and phase-in, there were constructed in railway over state-of-the-art radio communication networks. Therefore, there have been 3 wireless communication networks in domestic railways in accordance with running sections as like VHF, TRS-ASTRO and TRS-TETRA. For instance, the VHF networks were constructed in exsiting lines and TRS-ASTRO were Kyungbu HSL phase-1 except Seoul-Kwangmyung section, downtown in Daejeon City and that of Daegu City. And it was constructed in DongDaegu-Busan section of Kyungbu HSL phase-2, Osong-Kwangju section of Honam HSL phase-1 and would be done in Kwangju-Mokpo of Hanam HSL phase-2 and Soosu-Pyungtaek of Metropolitan Area Line by TRS-TETRA. In this paper, we described some important problems of radio communication management and investigated current state of radio communication for railways. Moreover, we presented the necessity of integrated radio networks for domestic railways.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 춘계학술대회 논문집
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• pp.467-472
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• 2002

The railway signal ing system consists of several vital computerized equipments. Now the project for development of signal ing system for the next-general ion high-speed train is progressed according to the consortium. The developing signal ing system by this project, kTCS(Korean Train Control System), is composed of kTCS-CTC, kTCS-IXL, kTCS-ATC and etc. The KTCS signaling has to be operated as a integrated system by interface between each signaling. To achieve these, communicat ion protocols between each signal ing have to be designed and message codes are defined. In this paper the configuration of integrated kTCS system and designed communication protocol is presented.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1838-1844
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• 2011

In this paper, the propulsion control of a high-speed maglev train is studied. Electromagnetic suspension is used to levitate the vehicle, and linear synchronous motors (LSM) are used for propulsion. In general, a low-speed maglev train uses a linear induction motor (LIM) for propulsion that is operated under 300[km/h] due to the power-collecting and end-effect problem of LIM. In case of the high-speed maglev train over 500[km/h], a linear synchronous motor (LSM) is more suitable than LIM because of a high-efficiency and high-output properties. An optical barcode positioning system is used to obtain the absolute position of the vehicle due to its wide working distance and ease of installation. However, because the vehicle is working completely contactless, the position measured on the vehicle has to be transmitted to the ground for propulsion control via wireless communication. For this purpose, Bluetooth is used and communication hardware is designed. A propulsion controller using a digital signal processor (DSP) in the ground receives the delayed position information, calculates the required currents, and controls the stator currents through inverters. The performance of the implemented propulsion control is analyzed with a small maglev train which was manufactured for experiments, and the applicability of the high-speed maglev train will be explored.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.305-310
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• 2008

최근 통신기술이 발달함에 따라 무선통신 주파수 대역폭은 더 넓어지게 되었고, 고집적 반도체 소자는 고속전철 시스템에 더 많이 적용되고 있다. 고속전철 시스템에서 사용되는 집적된 전력 반도체의 RFI (Radio Frequency Intereference, 라디오파 방해) 민감도 [또는 내성(耐性)]는 시스템의 안전에 많은 영향을 준다. 이 연구에서는 고속전철 시스템의 무선통신 주파수 대역에서 RFI 민감도 기준과 측정방법이 조사되었다.

• 한국전기전자재료학회논문지
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• 제24권6호
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• pp.497-503
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• 2011

Currently in Korea, the simple catenary type overhead contact line system is being applied to both conventional lines and high speed lines of electric railway, and circulation current flowing into the catenary system frequently bring undesirable consequences. Namely, the connector wire has many problems according to a flow of excessive circulation current and arc current on catenary when an electric train runs at high speed. This paper presents the development and application of a real-time data acquisition system designed to measure the electrical characteristics of an overhead catenary system in electric railways. The developed system is capable of storing data of a 25 kV power source in a live wire state through a telemetry environment. The field test results show that the proposed technique and the developed system can be practically applied to measure characteristics of current of an overhead catenary system.

• 한국산학기술학회논문지
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• 제15권4호
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• pp.2355-2362
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• 2014

전기철도 선로변에 포설되어 있는 통신선에는 유도전압이 발생하여, 통신품질 저하와 기기 오작동 및 안전문제를 유발할 수 있다. 이와 같은 유도전압은 전차선과 통신선의 자계결합에 의해 유발되며, 구조물이나 레일 등의 금속물이 근처에 있을 경우 차폐영향을 받는다. 본 논문에서는 통신선 주변에 금속관이 매설되어 있을 경우에 발생하는 차폐효과를 실험을 통해 정량적으로 분석하였다. 고속철도 현장에서의 실험 결과, 금속관이 통신선으로부터 1~2m 거리에 병행매설되어 있을 경우, 금속관의 차폐효과는 20% 정도인 것으로 측정되었다. 또한, 이격거리가 4m 이상인 경우에는 차폐효과가 1% 이내로 미미하다는 것을 확인하였다. 이상의 결과는, 수도관이나 가스관, 구조물의 철근과 같은 금속 설치물의 차폐효과를 분석하는 데 활용할 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.244-246
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• 2004

Compared with other transport means, safety and timeliness are the merits of railways. Unexpectedly when accident happens, much time and human strength are required to cope with the accident. And for swift recovery, systematic rehabilitation is needed. Recently using MTS(Moving picture Transmission System), we can perform accident rehabilitation and recording work efficiently. MTS is the device that transmits continuous picture information from accident field to control center. We are developing the appropriate system to railway situation to make use of the existing information communication technology, processing technology of video-tex, super high speed transmission technology through fiber-optic, copper cable and network description of information Technology, etc. If these communication-based can technologies are applied to railway system, railway managers can control the accident by inspecting the picture of accident field and can contribute to the safe train operation and the improvement of railway management. In this paper, we investigate the connecting methods when optical fiber is used for moving picture data transmission of train accidents, and its problems. And, we validate MTS's performance through about 28km section of field test.

• International Journal of Railway
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• 제1권1호
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• pp.12-19
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• 2008

Starting her business operation on January 5 2007, Taiwan High Speed Rail(THSR) shapes a new time-space frame for Taiwan western corridor, where more than 90% of national population lives around and more than 95% gross domestic product created from. Comparing with the four-hour traveling time by highway before 2007, THSR reduces the time required to one and half hours from Taipei to Kaohsiung. It will not only benefit the communication along the island from north to south, but also change the location advantages/disadvantages for all cities in these regions. Therefore, this paper establishes a spatial computable general equilibrium model(SCGE Model) to simulate the economic effect of High Speed Rail(HSR). This SCGE model divides Taiwan economy into fifteen geographic regions and thirteen industries. Each region has three sectors: household sector, transportation sector, and industries sector. Following the behavior function of economic theories, the general equilibrium can be achieved simultaneously. Thus, gross regional product (GRP), capital formation, employment income and welfare/utility level can be all observed by calculating the different economic result between cases with-/ without-HSR. Besides, this model presents the social welfare benefit from HSR operation, the polarization phenomenon among regions and within certain region, unbalance distribution of welfare along the HSR line, and industries development divergence among regions etc. These major findings should be useful for regional development policy making.

• 한국정보통신학회논문지
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• 제22권6호
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• pp.903-909
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• 2018

2017년 12월 원주~강릉구간 고속철도 개통과 함께 250km/h급 철도통합무선망(LTE-R)이 세계 최초로 상용화되었다. LTE-R은 음성 및 영상 통화, 고속 데이터 전송, 커버리지 이중화 및 DU 이중화 등 많은 장점이 있으나 UL, DL 각 10MHz의 한정된 대역폭을 사용하므로 효율적인 무선자원 활용이 필요하다. 기존의 Unicast 방식은 주파수 효율이 제안적으로 사용자 수가 증가할 경우 망 부하로 인하여 서비스에 제한이 있으며 이는 안정성과 신뢰성을 보장해야 하는 LTE-R 특성 상 큰 문제로 이어질 수도 있다. 반면 eMBMS를 통한 Multicast 방식을 적용하면 영상데이터와 같은 대용량 데이터 전송수가 늘어도 안정적인 서비스 제공이 가능하다. 본 논문에서는 이론전 계산값과 시험을 통해 LTE-R 망 부하를 고려한 Unicast 기반의 사용자 임계수를 도출하고 향후 LTE-R의 eMBMS 상용화 적용을 위한 고려사항을 제시하고자 한다.

• 한국산업정보학회논문지
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• 제17권2호
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• pp.19-27
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• 2012

In railway tunnel environment, the reliability of a high-data-rate and real-time train-to-wayside communication should be maintained especially when high-speed train moves along the track. In China and Europe, the communication frequency around 900 MHz is widely used for railway applications. At this carrier frequency band, both of the solutions based on continuously laid leaky coaxial cable (LCX) and discretely installed base-station antennas (BSAs), are applied in tunnel radio coverage. Many available works have concentrated on the radio-wave propagation in tunnels by different kinds of prediction models. Most of them solve this problem as natural propagation in a relatively large hollow waveguide, by neglecting the transmitting/receiving (Tx/Rx) components. However, within such confined areas like railway tunnels especially loaded with train, the complex communication environment becomes an important factor that would affect the quality of the signal transmission. This paper will apply a full-wave numerical method to this case, for considering the BSA or LCX, train antennas and their interacted environments, such as the locomotive body, overhead line for power supply, locomotive pantograph, steel rails, ballastless track, tunnel walls, etc.. Involving finite-difference time-domain (FDTD) method and uni-axial anisotropic perfectly matched layer (UPML) technique, the entire wireless RF downlinks of BSA and LCX to tunnel space to train antenna are precisely modeled (so-called integrative modeling technique, IMT). When exciting the BSA and LCX separately, the field distributions of some cross-sections in a rectangular tunnel are presented. It can be found that the influence of the locomotive body and other tunnel environments is very significant. The field coverage on the locomotive roof plane where the train antennas mounted, seems more homogenous when the side-laying position of the BSA or LCX is much higher. Also, much smoother field coverage solution is achieved by choosing LCX for its characteristic of more homogenous electromagnetic wave radiation.