• 전자공학회논문지
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• 제50권10호
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• pp.3-12
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• 2013

무선 센서 네트워크(WSN: Wireless Sensor Network)는 철도분야에서 효율적인 관리와 유지보수라는 측면에서 적용되어 사용되고 있다. 하지만 저속 철도 환경에서 사용되고 있는 현재의 IEEE 802.15.4/ZigBee 기반 센서 통신 기술을 차세대 고속철도에서 적용하기에는 열악한 무선 채널 환경에 노출되어 있다. 본 논문에서는 고속 철도 환경에 적합한 센서 통신 알고리즘을 제안한다. 에러율 및 전송률 향상을 위해 IEEE 802.15.4/ZigBee 기반 개선 알고리즘인 Equalizer, MIMO(Multiple Input Multiple Output), Flexible SF(Spreading Factor) 및 Modulation을 사용한다. 또한 IEEE 802.15.4/ZigBee 표준의 2.4GHz 대역 물리계층에서 각 알고리즘에 대한 성능을 비교 분석한다. 모의실험 결과, 제안한 알고리즘을 통해 기존 시스템보다 에러율 및 전송률이 향상 된 것을 볼 수 있다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2292-2299
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• 2011

The CBTC(Communication Based Train Control) system, a recent train control system, is a wireless communication based train control system that is operated in the moving block system control by tracking trains in real time. In additioin, the system helps to increase the volume of traffic by shortening driving headways through controlling moving block system control. Furthermore, driverless modes are performed by controlling ATP(Automatic Train Protection)/ATO(Automatic Train Operation). In this paper, controllable elements in ATO driverless train control system, affecting comfortable ride, will be analysed and applied to CBTC train control system that developed by POSCO ICT. Finally, the test results of improved comfortable ride will be showed by appling the developed system to the Gyeong-san light rail transit test track.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2705-2710
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• 2011

With the rapid development of information and communication technology, CBTC system based on the wireless communication is widely applied in the railway signal system recently. CBTC system has advantages of lower installation space and maintenance fee than existing systems and the increase of transportation capacity and improvement of operating efficiency etc. due to the short headway. Based on the continuous wireless data communication between onboard and wayside equipment, CBTC system not only locates the train and transmits the information required for the train control, but also implements the moving block function by calculating the brake curves continuously according to distance from the preceding train. CBTC system can use either inductive loop (IL-CBTC) or radio frequency transmissions (RF-CBTC). In this paper, we propose RF-CBTC system architecture based on the functional modules, in which the CAN bus network is applied for the interfaces between the modules.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.900-904
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• 2009

The measurement of contact wire uplift in electric railway is one of the most test method to accept the maximum permitted speed of new vehicles or pantographs. The contact wire uplift can be measured for shot periods when pantograph is running in monitoring station. This paper describes the development of two different methods for contact uplift measurement using vision-based system and wireless online monitoring system. Our vision-based system employs a high-speed CMOS (Complementary Metal Oxide Semiconductor) camera with gigabit ethernet LAN. The development of a real-time remote monitoring system that acquires data from any kind of sensor to be transmitted by wireless communication from overhead line and structure at 25 kV to a computer in catenary system. The proposed two kind of different measurement systems to evaluation for dynamic uplift of overhead contact wire shows promising on-field applications for high speed train such as Korea Tilting Train (TTX) and Korea Train eXpress (KTX).

• 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.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2007년도 하계종합학술대회 논문집
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• pp.99-100
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• 2007

Rapid developments of industry and economics have made a metropolis which demands an effective urban transport management system (UTMS). Specially, this paper considers a subway surveillance system based on integrated wireless LAN technologies for public safety. Since a current subway platform security entirely relies on conventional closed circuit television camera (CCTV) or human operators, subway train drivers cannot detect platform states and cope with abnormal situations or accidents immediately. However, through the IP cameras and some wireless routers, high qualify images of the platform conditions can be directly delivered to the train drivers and other station employees in advance of train entering the platform. In this paper, several design issues and problems are discussed when building up the subway management system. Further, we illustrate a system model with the system requirements in real parametric values in order to draw concrete system designs and to realize a practical implementation of the future UTMS.

• 한국철도학회논문집
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• 제16권4호
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• pp.262-271
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• 2013

최근 IT기술의 발달과 고속, 고밀도 운행을 요구하는 철도시스템에서 기존의 궤도회로기반 열차제어방식에서 새로운 개념을 도입한 통신을 이용한 열차제어로 변화가 됨과 동시에 유지보수의 효율화, 승객서비스 증대에 따라 철도시스템에서 무선통신이 중요한 역할은 담당하는 위치로 변경되고 있다. 본 논문에서는 철도시스템에서 통신의 역할을 분석하고, 수송력향상과 안전 확보 및 효율적인 열차제어를 위한 무선통신망 구축방안으로 국외의 사례 비교 및 검토를 기반으로 효과적인 방안으로 제시함으로써 철도시스템을 위한 최적의 철도 무선통신망의 구축을 도모하고자 한다.

• 대한토목학회논문집
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• 제44권3호
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• pp.417-423
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• 2024

This study compared and analyzed the importance of command priority between railway traffic controllers through pairwise comparison of AHP analysis. 27 railway traffic controllers working on metropolitan railway control center, urban railway control center, and unmanned driving control center responded. As a result of the analysis, all the railway traffic controllers generally recognized the train driving control and train signal control as the most important priorities. For the controller in the manned driving system, a train driving control was the highest at 0.375. On the other hand, the controller based on unmanned driving recognized train signal control as the highest priority at 0.469. In the result of the AHP analysis considering all the variables, the braking system was the highest priority at 0.19 based on manned train driving. On the other hand, the controller based on unmanned train driving recognized wired and wireless network systems and SCADA as the highest priority at 0.267.

• 한국초전도ㆍ저온공학회논문지
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• 제20권1호
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• pp.23-27
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• 2018

As the wireless power transfer (WPT) technology based on strongly resonance coupled method realizes large power charging without any wires through the air, there are advantages compared with the wired counterparts, such as convenient, safety and fearless transmission of power. From this reason, the WPT systems have started to be applied to the wireless charging for various power applications such as train, underwater ship, electric vehicle. This study aims for the effect and characteristics of different inserted resonance coil between Tx and Rx coils for charging system of superconducting magnetic levitation (MAGLEV) train. The transfer efficiency and effect are evaluated with helix type, rectangular type copper resonance coil, and HTS resonance coil under bulb and HTS magnet load, respectively. The input power is adapted with radio frequency (RF) power of 370 kHz below 500 W.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.772-777
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• 2008

Recent development of fiber optic sensors and wireless sensor technology, made structural health monitoring of railway structures cost effective. In this paper, a micro bending fiber optic rail pad sensors are evaluated for train axle force measurement. In order to assess the usability of FBG fiber optic sensors for short-term bridge measurement, the FBG sensors and conventional strain gauges are installed at the same points and the strain results are compared. Also the impact factors are calculated using the FBG strain responses and the results are compared with the conventional sensor responses. A running KTX train was instrumented with wireless sensor system to measure the vibration characteristics and the results are compared with conventional wire sensor system.