• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.574-582
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• 2018

In systems such as railways, automobiles, and airplanes, system malfunctions may lead to accidents, which often cause serious personal injury and economic loss. In previous studies, failure analysis has been performed, and safety measures derived using the component level information to reduce damage when a failure occurs. However, in functional safety concept, a focus is placed on lowering the frequency of occurrence of failures by performing risks analysis, setting up safety goals, and designing safety functions. Therefore, it is necessary to study how to determine the required safety function that can reduce the failure frequency to the acceptable level. To achieve this, we first studied a failure modeling method using SysML. It was then presented how several alternatives can be assessed to determine the desired safety function by simulating the generated SysML failure models and calculating the ability to reduce the failure frequency. A case study of a railway signaling system was done, demonstrating the effectiveness of the approach. We assessed whether the safety objectives were met for the alternative design of the railway signaling system through M & S. The results can be useful in that it can be applied from the early design phase and allow to choose the appropriate safety function that satisfies safety objectives among various design alternatives.

• Journal of the Korean Society for Railway
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• v.19 no.2
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• pp.159-169
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• 2016

The current railway control system in Korea is comprised of signaling, electric rail power, communication, and maintenance systems that are independent of each other. Further, these systems have different mediums and protocols for transmitting the field equipment data to the central control system. The Safety Supervision System has as its purpose the collecting of safety-related data from each system to predict and prevent accidents, this system utilizes standard protocol. Safety-related data need to be collected from field data transmission devices of the existing control system, the data should be collected without affecting the communication of the existing system. In this study, sniffing skill, which is typically used for network traffic monitoring or security, is used to collect data. The problems arising from the use of sniffing devices are noted, and the Packet Conversion Node is proposed as a solution to the problems. Further, functional and performance testing were completed for the prototype, and the software architecture and packet conversion process were verified.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.666-670
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• 2011

ATS(Automatic Train Stop)s are is effected by track environment, signal distance and train braking distance. So onboard signaling systems such as ATP(Automatic Train Protection) are installed on conventional lines by some train operation companies. With the mixed signalling, the onboard signaling system is overlaid on a conventional line with ATS, it is possible to run the line with conventional trains and ATP trains and to use the advantages of ATP(higher speed or more trains on the line). This paper includes guidelines a mixed signalling(ETCS and ATS) system architecture, operation concepts and infill balise installation.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.951-952
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• 2006

Railway signaling systems are so vital to ensure the safe operation of railroad and the assurance and demonstration of the safety is so important. The safety management process shall consist of a number of phases and activities, which are linked to form the safety life-cycle. The basic processes of safety management and safety activity throughout the lifecycle are 'risk analysis' and 'hazard control'. The safety managements and activities for the two kinds of aspects are implemented throughout the whole steps of system lifecycle. The risk analyses and hazard controls like those are needed, these activities have to be carried out through the whole of system lifecycle.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1195-1203
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• 2008

In this study it is researched to the hazard analysis phase which is the core phase of the safety life cycle carried out by various systems in Korea. At present diverse methods are utilized when the hazard analysis is performed. With the basis of these V&V activities are carried out. In this study using FMEA which is one of the representative methods of the hazard analysis, the effective and viable result is derived. Also, it establishes the systematic base of the further phases of the safety life cycle such as the Hazard log, V&V, and the safety case.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.879-880
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• 2009

안전필수시스템인 철도제어시스템은 고신뢰성과 고품질을 위해 국제표준에 의해 정형기법의 사용이 요구되고 있다. 시스템 개발 생명주기에서 요구사항 명세와 검증, 설계 명세와 검증단계에서 정형기법이 사용된다. 본 논문에서는 요구사항 명세 및 검증단계에서의 정형기법 사용을 목적으로, 정형요구명세 개발을 위한 템플레이트를 제안하고 이를 이용한 개발 프레임워크를 제안한다.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.471-473
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• 1999

Recently, the computer based control systems instead of conventional relays circuitry are widely used to industrial applications, and also those technology is available to railway signaling which are safety-critical systems. However, the safety and reliability of software for those systems are harder to demonstrate than in traditional relays circuitry because the faults or errors can not be analyzed and predicted to those systems. So, the safety problems are crucial more and more in computer based control system. In this paper, the GRAFCET(GRAphe Fonctionnel do Commande Etape/Transition) language is used as a analysis and verification tool for safety-critical interlocking logic. The general description for Grafcet notation are provided and the general modeling for interlocking logic is presented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.4171-4176
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• 2012

The conventional block systems for railway signaling currently in operation in Korea have not been electrified or integrated and therefore there have been difficulties in terms of construction and maintenance. Two independent systems have been installed for ABS and LEU of ATP system (for speeded-up lines), although they deal with the same signaling information at the same location in order to control the trains. In these conventional ABS and LEU, a number of duplicate modules are installed in each device including lamp detection units and power supply units and it results increased manufacturing costs and maintenance efforts. This paper deals with the prototype development of integrated electronic block system with CPU-based digital control methods in order to overcome the limitations of the conventional ABS. The suggested system is the integration of the conventional ABS with LEU of ATP and it is also applicable for the non-ATP sections as well.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2983-2988
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• 2010

The train control system used in Gyeongbu-line is classified in ATC, IXL and CTC. Domestic railway signaling systems are being developed by electrification. In these systems the electrification of interlocking reaches 57% and the safety equipments of railway crossings in trackside devices have completed their development into an integrated system. Block systems of all the existing sections have not yet electrified and integrated so that they need a number of complement in terms of construction and maintenance. For ABS currently used in existing domestic lines, and LEU being installed in Gyeongbu and Honam lines, although a train is controlled by the signaling information of the same train in the same location, the system is separately installed so that the same information is separately divided and transmitted at the each distinct system. Therefore, in the conventional ABS and LEU, there are a lot of duplicate installed compartments such as lamp detection and a power supply unit. Hence, we have a lot of problems: for maintenance, a lot of manpower and costs need to be invested and the overall manufacturing costs get higher, as well as the construction costs by duplicate. Therefore, this paper suggest design to develop an integrated electronic Block Control Unit by the integration of the currently used ABS, and communication and electronic technology. We are to monitor and manage the block systems in the corresponding station by integrating. And we are to transmit information together with LEU, which is an ATS wayside transmitter.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.31-45
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• 2017

According to the railway accident statistics in recent years, the frequency of accidents has been significantly reduced, due to the advance of related technologies and the establishment of safety information management systems. Nonetheless, accidents due to errors in the operation and maintenance phase and faults in safety design continue to occur. Therefore, to prevent accidents, guidelines for the safety design and manufacture of railway vehicles were established, and a request for the independent safety evaluation of safety designs was made. To respond to this, rail system developers must prepare safety cases as a safety activity product. One of the main items of these safety cases is the safety-related application conditions (SRAC) and, thus, the question of how to develop these SRAC is an important one. The SRAC studies reported so far focused only on the simplicity of the derivation procedure and the specific safety activities in the design phase. This method seems to have the advantage of quickly deriving SRAC items. However, there is a risk that some important safety-related items may be missing. As such, this paper proposes an improved method of developing the SRAC based on the idea of performing both the safety design and safety evaluation activities throughout the whole system lifecycle. In this way, it is possible to develop and manage the SRAC more systematically. Especially, considering the SRAC from the initial stage of the design can allow the safety requirements to be reflected to a greater extent. Also, an application case study on railway signaling systems shows that the method presented herein can prevent the omission of important safety-related items, due to the consideration of the SRAC throughout the system lifecycle.