• 시스템엔지니어링학술지
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• 제10권2호
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• pp.43-50
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• 2014

The Centralized Traffic Control(CTC) System of Urban Railway is an element(subsystem) of the Urban Railway system to aim safety operation and efficient management of rolling stock in accordance with a train scheduling program in train operation ways. That's why the CTC System must be developed considering systematic and safety-guaranteed methods such as RAMS(Reliability, Availability, Maintainability, and Safety) refereed to IEC standards. The CTC System is consists of rolling stock, signaling, power supply, communication, and mechanical equipment and preforms control and remote monitoring functions. The technical activities considering safety process are very important at such an early stage of development in a railway project. This paper introduces RAMS activities and an independent safety assessment by $3^{rd}$ Party focused on a safety applied to a development of the CTC system of Urban Railway and proposes the experiences as well practices.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.959-963
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• 2007

After the year of 2000, the need of safety increases in field of railroad. The project for developing Integrated Centralized Traffic Control(CTC) center started at 2002 to control the full domestic railroad network. A traffic control software was required the safety activity and assessment, according to 'KORAIL Instruction number 2001-49'. There were many trials and errors to perform safety activity because the technology and recognition of safety activity is in primary stage. However the safety activities are gradually stabilized. This paper describes the safety life-cycle and development life-cycle of Integrated CTC S/W and a suitable life-cycle of safety to develop S/W of Integrated CTC.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권7호
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• pp.309-316
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• 2005

In this paper we analyzed a dangerous failure and a safety requirement based on HIA (Hazard Identification and Analysis) of an interface model between CTC (Centralized Traffic Control) system and El (Interlocking) system, and assigned SU (Safety Integrity Level) by way of an risk estimation of the interface, which employed PHA (Preliminary Hazard Analysis) for the interface of the track control system, being managed as separated system between the centralized traffic control system and the interlocking system, An estimation which satisfies a safety reference of the international standard has been achieved through a quantification of the system failure rate and the dangerous failure rate of the interface model.

• 한국통신학회논문지
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• 제42권4호
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• pp.768-779
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• 2017

최근 급격히 증가한 모바일 기기의 활성화로 인하여 CMM 기반의 LTE/EPC 네트워크에 과다한 데이터/제어 트래픽의 수용이 힘들어지는 문제가 중요 이슈로 부각되고 있다. 이를 해결하기 위하여 IETF에서는 Distributed Mobility Management (DMM) 기반의 이동성 관리 방안을 제안하였다. 하지만, DMM 기술은 중앙의 트래픽 부하 분산에 초점을 두고 있어서 과다한 제어 트래픽 수용에 관한 문제를 해결하기에는 부족하다. 따라서, 본 논문에서는 이러한 문제를 해결하기 위하여 SDN을 기반으로 CMM과 DMM을 함께 이용하는 C-DMM LTE/EPC 네트워크 구조를 제시한다. 이를 위하여, 기존의 LTE/EPC 네트워크 구조 변경을 최소화 하면서도 효율적인 DMM을 지원하기 위하여 기존 P-GW와 유사한 기능을 수행하는 Packet Data Network Edge Gateway (P-EGW)를 LTE 단말에 근접한 위치에 분산 배치하는 새로운 LTE/EPC 모델을 제안하고, 이를 위하여 단말의 이동성 및 PDN 연결 개수에 따라서 CMM과 DMM 기법 사이 중 하나를 선택하는 방안을 제안한다. 마지막으로, ONOS 컨트롤러와 Mininet 환경에서 각 기법들 사이의 데이터 처리량 및 제어 트래픽의 처리량을 비교하여 제안하는 네트워크 구조 및 기법에 대한 타당성을 입증한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.928-931
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• 2007

In answer to the increase of demand for the safety in railroad, the safety activities are tried out. According to 'KORAIL Instruction number 2001-49', the project for developing Integrated Centralized Traffic Control Center has been carried out and the safety activities are guaranteed by documents named 'Safety Plan' and 'Safety Requirements' from this project. However the development system is not enough for the full safety activities. Therefore this paper we describes the relationship of safety activities and development systems and proposes the efficient direction of safety activities.

• 한국통신학회논문지
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• 제25권9A호
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• pp.1405-1412
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• 2000

In this paper, we propose an efficient dynamic wavelength assignment algorithm in distributed WDM (Wavelength-Division Multiplexing) networks without wavelength conversion. The algorithm tries to assign a locally-most-used wavelength distributedly on a fixed routing path. We first formulate our algorithm by using the concept of a sample space which consists of optical fibers connected to nodes on a routing path of a lightpath to be assigned a wavelength. In particular, we analyze the blocking performance mathematically as compared with that of the most-used (MU) wavelength assignment algorithm previously proposed for WDM networks under centralized control. We also obtain numerical results by simulation on the blocking performance of other centralized/distributed wavelength assignment algorithms as well as our algorithm using the M/M/c/c dynamic traffic model. Consequently, we show that analytical results match simulation results and that our algorithm is efficient in distributed WDM networks in terms of blocking performance, control traffic overhead and computation complexity.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권9호
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• pp.485-490
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• 2006

According to the computerization of railway signaling systems, the interface link between the signaling systems has been replaced by the digital communication channel. At the same time, the importance of the communication link is more pronounced than before. In this paper, new Network-based protocol between railway signaling and SCADA (Supervisory Control and Data Acquisition system) has designed and the overview of designed protocol is briefly represented. And also this paper addresses analysis of newly designed train control systems. Fame error rates of the data transmissions are calculated and compared for the two cases that the CTC (Centralized Traffic Control)/SCADA has an extra data transmission error control (CRC16) besides the inherent error control of the Ethernet and that the CTC/SCADA has no extra data transmission error control. With simulation results it has been verified that the additional error control code contributes to lowering the frame error rate. It will be expected to increase the safety, reliability and efficiency of maintenance of the signaling systems by using the designed protocol for railway signaling system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.528-533
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• 2004

The purpose of this thesis is to construct the autonomous decentralized train traffic management structure using techniques of Autonomous Decentralized System. Currently, a method of train traffic control is making use of CTC(Centralized Traffic Control). Its operation method is divided into the remote mode and the local mode. The classified basis is according to the control authority of install signals in track side. In most cases, a large scale station is operated by the local mode. Because of dispatchers in center can not control the shunting works influence on the main route. In order to solve these problem s, we analyzed a current operation condition and system requirements. Moreover, this thesis is constructing autonomous decentralized train traffic management structure. Finally, this research proposed that interface with CTC and step-by-step construction.

• 전기학회논문지P
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• 제53권1호
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• pp.32-39
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• 2004

Railway signaling systems consist of several vital computerized equipment such as CTC(Centralized Traffic Control), EIS(Electronic Interlocking System), ATC(Automatic Train Control) and so on. Currently, the project for development of railway signaling systems for the next-generation high-speed train is progressed according to the G7 project and railway signaling related several companies and research institute are joined this project consortium. The railway signaling systems, being developed in this project, called as a kTCS(Korean Train Control System), is composed of kTCS-CTC, kTCS-IXL, kTCS-ATC and etc. kTCS signaling systems have to be operated at the laboratory testing level as integrated signaling systems by interface between each railway signaling systems before railway field installation and revenue service. To solve this matter, communication protocols between each signaling equipment are designed and message codes for each defined protocols have defined. And also several equipment has developed for the railway integrated signaling systems for laboratory testing. We has plentifully tested and verified the designed protocols and the characteristics of integrated railway signaling systems with our developed each kTCS signaling equipment and communication protocols. In this paper, the integrated kTCS system including communication protocols is presented.

• 디지털콘텐츠학회 논문지
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• 제14권3호
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• pp.283-290
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• 2013

PMIPv6과 같은 현재의 중앙 집중형 이동성 제어 프로토콜들은 모든 제어 트래픽과 데이터 트래픽을 함께 처리하는 중앙 집중형 이동성 앵커(central mobility anchor)에 전적으로 기반하여 동작한다. 그러나, 이러한 중앙 집중형 이동성 제어 프로토콜들은 코어망으로 트래픽이 집중되는 현상이 발생될 수 있거나, 이러한 중앙 집중형 이동성 앵커의 장애 발생 시 서비스 제공 불능현상 등이 발생될 수 있는 심각한 문제점을 안고 있다. 따라서, 본 논문에서는 이러한 문제점들을 완화시키기 위해, 사용자 이동 지역성을 고려한 PMIPv6 기반의 분산형 이동성 제어 기법을 제안한다. 성능 분석 결과, 제안 기법은 PMIPv6 및 관련된 분산형 이동성 제어 기술인 S-PMIP과 비교해 볼 때, 총 이동성 제어 비용을 대폭 감소시킴과 동시에 이러한 문제점들을 상당부분 해소시킬 수 있음을 입증한다.