• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.7
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• pp.628-637
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• 1990

In this paper we present on architecture for a high sppeed CMOS multiplier which can be used for real-time digital signal processing. And a synthesis method for designing highly parallel algorithms in VLSI is presented. A parallel multiplier design based on the modified Booth's algorithms and Ling's algorthm. This paper addresses the design of multiplier capable of accpting data in 2's complement notation and coefficients in 2's complement notation. Multiplier consists of an interative array of sequential cells, and are well suited to VLSI implementation as a results of their modularity and regularity. Booth's decoders can be fully tested using a relatively small number af test vector.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1209-1212
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• 2008

The high-speed EMU is assembled with distributed EMI sources. Therefore, it contains more electromagnetic sources nearby the distributed victims than the existing concentrated traction system. The electromagnetic sources and victims are identified in this research, and the methodology how to handle EMI/EMS/EMC of the high-speed EMU will be developed for safer operation. It includes measurement method, safety standards of control units and others, and performance evaluations of the firstly developed trial products for the EMU. Also influences by modern telecommunication equipments and effect of PLD(power line disturbance) are to be surveyed in this research.

• Journal of Internet of Things and Convergence
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• v.8 no.6
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• pp.55-63
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• 2022

In recent years, with the rapid development of large and medium-sized urban rail transit in China, the total operating mileage of high-speed railway and the total number of EMUs(Electric Multiple Units) are rising. The system complexity of high-speed EMU is constantly increasing, which puts forward higher requirements for the safety of equipment and the efficiency of maintenance.At present, the maintenance mode of high-speed EMU in China still adopts the post maintenance method based on planned maintenance and fault maintenance, which leads to insufficient or excessive maintenance, reduces the efficiency of equipment fault handling, and increases the maintenance cost. Based on the intelligent operation and maintenance technology of PHM(prognostics and health management). This thesis builds an integrated PHM platform of "vehicle system-communication system-ground system" by integrating multi-source heterogeneous data of different scenarios of high-speed EMU, and combines the equipment fault mechanism with artificial intelligence algorithms to build a fault prediction model for traction motors of high-speed EMU.Reliable fault prediction and accurate maintenance shall be carried out in advance to ensure safe and efficient operation of high-speed EMU.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.3
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• pp.291-297
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• 2014

Due to the rapid increase in demand for transportation of human and freight in modern railway systems, the CBTC system has been proposed, which is the solution for improvement of the line capacity that has been limited by the conventional track circuit based train control system. In the CBTC system, higher reliability of the communication system should be guaranteed for the safety of passengers and trains. However, due to the inherent characteristics of the wireless channel environment, performance degradations are inevitable. The diversity techniques can increase the reliability of data transmission using multiple antennas. In this paper, we investigate the performance of the STBC in the railway channel environment. Rician fading model is used for the viaduct scenarios which take important roles in the railway system. Also, considered is the Doppler effect which is an important factor in the mobile communication system. Simulations are performed to analyze the performance of the STBC in various channel environments. Results show that the performance degradation due to the phase error in viaduct scenarios is independent of the diversity order but is affected by the constellation of the modulation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.347-350
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• 2009

The opening of High-speed Rail provides convenience to move a long distance quickly, and the passengers of high-speed railway have been steadily increasing each year. Since the high-speed rail is far more expensive than other transportation, providing high quality service over just the high speed is required. Accordingly, much effort is made to improve service quality. However these services have been focused on general passengers so we should introduce a new service system to meet personal preferences of passengers. Therefore, in this paper, we introduce integrated railway service systems to provide service which follows the individual needs of passengers and is based on RFIDs (Radio Frequency Identification).

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.4
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• pp.831-837
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• 1999

본 논문에서는 Viterbi 복호기의 동작을 고속화할 수 있는 구조를 제시하였고, 제시된 방식으로 설계된 Viterbi 복호기를 CPLD 칩으로 구현하였다. Altera사의 Design Compiler를 이용하여 FLEX10K 칩에 합성한 Viterbi 복호기는 최고 20[Mbps]급 전송속도를 갖고 있으며, ASIC 설계시 100Mbps 이상의 속도가 가능하므로 고속 무선멀티미디어통신 시스템의 오류정정부호로 적용될 수 있다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.527-530
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• 2017

LTE-R(Long Term Evolution-Railway) based on LTE technology is expected to use core communication technology for high speed railway as one of standards for railway communications. In this paper, transmission performance of video traffic as an application is analyzed on LTE-R networks. Performance is evaluated with compter simulation based NS(Network Simulator)-2, open video traffic is used, RTP(Real Time Protocol) is used for transmission protocol. Results and methods of this paper can be used for research and developmemt of LTE-R networks.

• Journal of the Korean Society for Railway
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• v.19 no.4
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• pp.456-467
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• 2016

Wireless Access in Vehicular Environments (WAVE) communication technology, which provides vehicleto-vehicle and vehicle-to-infrastructure communication and offers safe and convenient service, has been developed for application to an Intelligent Transport System (ITS). This paper provides field test results on a study of the feasibility of WAVE technology application to railway communication systems. A test railway communication system based on WAVE technology has been built along the Daebul line and a newly developed EMU. Field tests have been carried out according to the communication function requirements for LTE - R. The test results show that the railway communication system based on WAVE technology meets the functional requirements: maximum transmission length is 730m, maximum transfer delay is 5.69ms, and maximum interruption time is 1.36s; other tests including throughput test, video data transmission test, VoIP data test, and channel switching test also produced results that meets the functional requirements. These results suggest that WAVE technology can be applied to the railway communication system, enabling Vehicle-to-Wayside communication.

• Information and Communications Magazine
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• v.19 no.11
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• pp.85-108
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• 2002

향후 다양한 무선 통신 규격들의 통합 수용을 위한 SDR (Software Defined Radio) 기술이IMT-2000 이후의 4세대 이동 통신 시스템을 위한 핵심 기술로써 심각하게 고려되고 있다. 이에 부응하여 SDR기반의 멀티모드용 통신 시스템을 구성하기 위한 주요 기술로서 디지털 IF 기술에 대한 필요성이 급속도로 고조되고 있는 상황이다. 최근 ABC/DAC 및 범용 디지털 신호처리 소자들의 고속화 및 고성능화로 인해 If (Intermediate Frequency) 대역과 기저대역 신호들 간의 직접 디지털 변환의 구현이 현실화되고 있다. 사용자의 관점에서 국지적으로 상용화되고 있거나 장래에 출현할 다양한 이동 통신 시스템 규격들 및 이에 대해 사업자들에게 할당되는 주파수 대역들이 서로 다른 점을 고려할 때, 이종 시스템 혹은 사업자들에게 할당된 주파수 대역에 구애받지 않고 언제 어디서나 자유롭게 무선 채널을 엑세스하고 또한 특정 채널을 임의로 선택하기 위한 디지털 If기술의 실현이 필수적이다 이러한 SDR기반 디지털 If 기술은 소프트웨어적으로 재구성 가능한 하드웨어 구조를 요구하며, 특정 이동 통신 규격의 물리 계층만을 지원하는 무선 인터페이스가 아닌 다중이동 통신 모드를 지원할 수 있는 유연성이 가미된 채널화 알고리즘이 필요하게 된다. 따라서 디지털 If기술은 무선 인터페이스 처리 부분, 즉 주파수 상 하향 변환 및 채별 선택 조합을 용도에 맞게 단일의 하드웨어 플렛폼 상에서 고속 디지털 신호처리 알고리즘을 기반으로 동작하기 위한 기능을 필연적으로 요구한다. 본 논문에서는 향후 SDR 기반의 기지국 및 단말기 운영 및 구생 모델을 제시하며, 디지털 If에 대한 필요성 및 동작 원리, 그리고 요소 기능들에 대한 구체적인 동작 원리 및 디지털 If와 더불어 활용 가능한 기술에 대하여 논의한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.843-846
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• 2009

경부고속전철의 급전선에 의한 전력유도 대책을 위하여 건설 당시 정보통신부 고시에 의하여 시행되었다. 통신선에 장애를 유발할 수 있는 전자유도 대책을 위해서는 국가 기술기준에 의한 유도전압 한계치가 정해져 있고 현장 대책 상 이 제한치를 초과할 때에 필요한 것이므로 상기 정부 고시의 기술 근거에 의해 유도전압을 계산하여 조치하고 있다. 전기철도시스템에서 지역 구간상의 전력 공급을 위한 일정 거리마다 급전소가 시설되어 있어서 이로부터 전철에 전력이 공급되고 있다. 전철의 유도현상에 의한 유도전압 분포 분석을 위한 전국 구간 유도측정을 수행하여 급전구간에서의 유도전압 특성을 파악하였다. 구간 중심점상에서 낮아지는 전압에 대해 급전소 근접 구간에 이르렀을 때의 전압 상승 특성을 분석하였다. 급전소로부터 귀로되는 전류의 양이 집합됨으로 유도전압이 높아지고 거리가 멀어질수록 전압은 떨어진다. 유도대책을 전압 분석에 있어서와 차폐시설물의 연계 활용 시 이러한 전압의 영향성을 고려할 필요가 있다.