• 한국철도학회논문집
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• 제16권6호
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• pp.540-550
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• 2013

본 논문에서는 철도통신시스템을 위해 필요한 주파수 소요량을 계산하기 위한 방법을 제안한다. 철도통신시스템을 위한 주파수소요량 계산에 최적화된 방법을 유도하기 위하여, 먼저 기존의 일반 이동통신시스템의 주파수 소요량 측정에 사용되었던 방법인 ITU-R M.1390을 분석한 후, 차세대 철도통신시스템에서 요구하는 서비스들을 세분화하여 정의하고, 철도통신을 위해 수정된 주파수 소요량 프로세스를 제안한다. 그리고 실제 현장조사를 통해 습득된 장비정보들을 제안한 계산방법에 적용하여 현재, 5년 후, 10년 후 시점의 예상 주파수 소요량을 계산한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1264-1269
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• 2008

We designed a track circuit of Tag in-tag out type that can be used for light rails and monorails. This method is called RFID-Tag and it literally uses RFID-Tag and replaces a fixed track circuit and implements a moving block. The distance between RFID-Tags is set to the length of a train and thus a train is always in contact with one of the tags. A train runs in RFID-Tag in -RFID-Tag out type at all times and the distance between trains can be precisely controlled through the application of a moving block combined with the basic principle of a fixed block, which enables the continuous speed control and enhances the satisfaction of passengers. When constructing a track circuit using RFID-Tag the Tag in-tag out brings us the cost reduction and is more economical than the existing fixed track circuit in that sense and easy for installation and maintenance. The wireless communication between onboard and wayside makes the continuous control possible and can improve the control capacity of ATP/ATO by the implementation of a moving block on top of a fixed one.

• International Journal of Railway
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• 제3권2호
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• pp.39-45
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• 2010

The RF-CBTC (Radio Frequency-Communication Based Train Control) System is a communication system in railroad systems. The communication method of RF-CBTC system is the wireless between the wayside device and on-board device. The wayside device collects its location and speed from each train and transmits the distance from the forwarding train to the speed-limit position to it. The on-board device controlling device controls the speed optimum for the train. In the case of the RF-CBTC system used in Korea, transmission frequency is 2.4 [GHz]. It is the range of ISM(Industrial Scientific and Medical equipment) band and transmission of voice and data is performed by CDMA (Code Division Multiple Access) method. So noises are made in the AWGN (Additive White Gaussian Noise) and fading environment. Currently, the SNR (Signal to Noise Ratio) is about 20 [dB], so due to bit errors made by noises, transmission of reliable information to the train is not easy. Also, in the case that two tracks are put to a single direction, it is needed that two trains transmit reliable voice and data to a wayside device. But, by noises, it is not easy that just a train transmits reliable information. In this paper, we estimated the BER (Bit Error Rate) related to the SNR of voice and data transmission in the environment such as AWGN and fading from the RF-CBTC system using the CDMA method. Also, we supposed the SNR which is required to meet the BER standard for voice and data transmission. By increasing the processing gain that is a ratio of chip transmission to voice and data transmission, we made possible voice and data transmission from maximally two trains to a wayside device, and demonstrated it by using Matlab program.

• 전기학회논문지
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• 제64권9호
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• pp.1398-1405
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• 2015

Domestic railway communication in Korea has been introduced for mutual communications among control center, operation staffs, and maintenance staffs. It has been mainly used as railway disaster and safety functions from VHF and UHF from 1980’s and TRS-Astro and TRS-Tetra from the 2000’s. Recently for urban railways communications, 18GHz and 2.4GHz ranges have been utilized for image transmissions and control command communications, respectively. This paper analyzes technical development of LTE-R, LTE communication for Railways, that has been designed as a single integrated railway wireless network in order to merge the current various communication systems. In this paper, we present the details of the examination of the LTE-R test-bed using 2.6GHz test frequency in Daebul test line through CW test and optimization test.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.101-102
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• 2007

Heart diseases are critical and should be detected as soon as possible. A stethoscope is a simple device to find cardiac disorder but requires keen experiences in heart sounds. We evaluate a cardiac disorder classifier by using heart sounds recorded by a digital wireless stethoscope developed in this work. The classifier uses hidden Markov models with circular state transition to model the heart sounds. We train the classifier using two kinds of data: One recorded by using our stethoscope and the other sampled from a clean heart sound database. In classification experiments using 165 sound clips, the classifier shows the classification accuracy of 82% in classifying 6 cardiac disorder categories.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권6호
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• pp.278-285
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• 2003

This paper proposes a new position detection method for train speed control using the Phase Difference of Arriving. This method aims to apply to Automated Guide-way Transit systems, to be operated without driver. So it is absolutely required to range, calculate and decide a train position precisely. This system consists of Vehicle Radio Set(VRS) and Wayside Radio Set(WRS). The VRS transmits a wireless signal to the WRS and the controller calculate a straight line and curve line with Phase Difference of Arriving(PDOA) and an exact position using track date-base is calculated at next step.

• 한국산학기술학회논문지
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• 제21권9호
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• pp.1-8
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• 2020

국토교통부는 2012년부터 주요 철도 정책으로 철도전용의 통합무선망 기술 확산에 노력했다. 그 결과, 2017년 세계 최초로 LTE 기반 철도통합무선망(LTE-R)을 강릉선 KTX 노선에 (만종역-강릉역) 구축 완료하였으며, 현재 해당 구간에서 LTE-R 통신 시스템을 상용 운영 중이다. 안전하고 효율적인 열차 운행을 위하여 철도통합무선망은 그룹통화, 긴급통화, 철도전용 호처리, 무선통신 기반 열차제어를 수행함에 따라 통상적인 무선통신과 차별화된 철도전용의 통신 기능과 성능요구사항이 존재한다. 본 논문에서는 철도통합무선망이 갖춰야 하는 기능 및 성능 요구사항을 유럽 철도통합 무선망의 분석을 통하여 제시하고, 아울러 강릉선 KTX에서 실제 측정한 LTE-R 무선통신의 특성과 성능을 기반으로 현재 구축된 통신망의 적정성과 안정성에 대한 분석을 수행하였다. 해당 노선의 평균적 전파품질이 열차제어를 위한 통신 요구사항을 만족하더라도 일부 구간에서 RLF(Radio Link Failure)와 같은 급격한 통신 성능저하를 확인하였다. 본 논문에서는 필드 테스트를 기반으로 하는 LTE-R 무선통신 분석을 바탕으로 향후 열차제어를 위한 네트워크 구축과 성능개선 방향을 제시한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.904-909
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• 2011

The development of train control system shall operate a series of processes like system designing, system production and system performance evaluation as a result of various requirements analysis presented in operation rules, operating guidelines for railway organizations etc, notified by the nation. Therefore, considering operation conditions, operation plan, linkage to railway network etc, the major document like system functional specifications, system development specifications, system test plans etc must be drawn up. In this paper we classify system operating scenarios required to prepare for system standard specification and system performance evaluation report of CBTC system for urban subways supporting unmanned automatic operation, and adjust each of the operating status.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.82-87
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• 2005

The new technology with Wireless LAN (WLAN) is implemented to the railway system, which is attached importance to safety and reliability. Railway control system based on WLAN that is called CBTC (Communication Based Train Control) is being developed by the advanced nations in this field and The system is applied to a new train line and a renovation for outworn equipment. The CBTC system has many merits about increase of capacity, reduction of headway and cost reduction etc.. Therefore, that is come into spotlight to the advanced railway company and the companies have being developed the system. So, we have developed the CBTC system for standardization and localization of the railway signal system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1576-1578
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• 2005

기존 국내의 간선 철도와 도시철도에서는 궤도회로에 기반한 고정폐색방식에 의한 열차제어시스템을 사용하고 있으나, 세계적인 추세가 유지보수 비용을 줄이고 선로 용량을 증가시킬 수 있는 무선통신을 이용한 이동폐색방식에 의한 새로운 통신기반 열차 제어 시스템(CBTC(Communication Based Train Control) system)에 대한 연구가 활발히 진행되고 있으며, 특히 도시철도의 경우 이에 대한 실용화가 이루어지고 있는 실정이다. 현재 국내에서도 한국철도공사에서는 분당선 구간에 CBTC 시스템의 시범적응을 진행하고 있으며, 또한 한국철도기술연구원에서도 건설교통부가 추진하고 있는 도시철도 표준화 사업의 한 분야로 도시철도 신호시스템에 대한 향후의 표준화 방향을 CBTC 시스템으로 선정하고, 이에 대한 표준화 및 국산화 연구개발이 진행되고 있다. 또한 유럽에서 진행되고 있는 ERTMS/ETCS 시스템의 레벨 2와 3에서는 앞의 방식하고는 다른 GSM-R의 무선방식을 사용하고 있지만 이 또한 무선통신에 의한 열차제어시스템을 적용하고 있다. 본 연구에서는 이러한 무선통신을 이용한 열차제어시스템에 있어서의 안전제동모델에 대해 연구하였으며 그 결과를 소개하고자 한다.