• 전기학회논문지P
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• 제64권3호
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• pp.138-142
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• 2015

Most of the existing studies on functional safety testing for the railway signaling system software have focused on verifying the functional safety through the monitoring of internal memory embedded railway signaling system. However, the railway signaling system is one of the typical embedded control system in the railway sector, and the embedded software has a characteristic of generating an appropriate outputs through the combination of internal processing in consideration of the current internal status and external input. Therefore, the test approach of using the interface communication channel can be effective way for the functional testing for railway signaling system software in consideration of these characteristic. Since a communication interface specification of the railway signal system has a the properties of the sequence input and output signals, test-case for software testing is the most effective methodology by MSC (Message Sequence Chart) language, one of the graphic language. The MSC-based test-case generating methodology for signaling system software was proposed in this paper.

• 한국철도학회논문집
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• 제12권4호
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• pp.450-456
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• 2009

최근의 컴퓨터 기술의 발달에 따라 열차제어시스템들이 컴퓨터 소프드웨어에 의존성이 더옥 증가되고 있으며, 이에 따라 이러한 열차제어시스템 소프트웨어의 안전성과 선뢰성에 대한 테스팅이 더욱 증요하게 되었다. 본 논문에서는 이러한 열차제어시스템 소프트웨어를 위한 Metrics 분석 자동화 도구를 제안하였으며, 또한 구현결과를 제시하였다. S/W Metrics는 철도시스템 소프트웨어관련 국제표준에서 언급되고 있는 Metrics를 대상으로 하였으며, 철도 소프트웨어 소스코드의 Metrics를 자동으로 분석하여 그 결과를 사용자에게 다양한 형태로 제시할 수 있도록 구현하였다. 자동화 도구는 열차제어시스템 소프트웨어 평가단계에서도 활용될 수 있고 또한 소프트웨어 개발단계에서도 유용하게 활용될 수 있을 것으로 예상된다.

• International Journal of Railway
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• 제9권2호
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• pp.36-40
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• 2016

TETRA communication system is very versatile system which can transmit voice + data and packet data optimized. Direct mode operation permits to connect between mobiles when mobile stain is out of coverage of networks. It can be more secure communication channel for railway signaling systems. Railway signaling systems use many of wayside signal equipment, which require many maintenance efforts and budget. Many railway authorities want to reduce and replace the wayside equipment. Radio based signaling systems are one of candidate for replacing the conventional signaling systems. The radio based signaling systems can replace track circuit and wayside signal. The radio systems permit to connect between control centers and trains. The radio systems have to ensure high quality of the connectivity more or equal to the existed track circuits. We studied the application of TETRA systems for railway radio systems for bridging between train control centers and trains. We provide an operation scenario for radio based train control system to ensure the safety require to the existed trains control system and satisfied the existed operational availability. We showed the data transmission speed, maximum bit error rate, and data coding for the radio-based signal system using TETRA systems.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2795-2803
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• 2011

Due to speed acceleration, higher requirements have been put forward to high speed railway communication and signaling system. The railway applications, including intra-train, train to ground and trackside networks, demand larger bandwidth, higher reliability and shorter response time from railway communication networks to ensure security operation and passenger communication. However, the current railway communication and signaling system has lagged behind the railway development, so advanced communication technologies are needed to improve the current situation. This paper presents high speed railway communication and signaling system based on 4G LTE technology, introduces its network architecture, key technology and analyzes its technical advantages compared with GSM-R system. According to analysis, LTE based high-speed railway communication network is more effective and reliable.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1193-1198
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• 2004

This paper describes the lightning protection system for railway signaling equipments installed at subway car depots in Seoul metropolitan Rapid Transit Cooperation. Several measures for improving lightning protection performance are adopted; newly organized grounding system for neutral line of power system, rolling method to minimize damages induced by direct lightning strike, new measures to reduce voltage differences between the signaling equipments and the ground, and improvement of grounding system. The proposed system has greatly reduced the grounding resistance and also the voltage difference between the signaling equipments and the ground, and has prevented the accident related with lightning surges since it was installed. The proposed approach can be viewed as a useful alternative of dealing with lightning protection for railway signaling equipments.

• 한국철도학회논문집
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• 제7권2호
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• pp.114-119
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• 2004

According to the computerization of railway signalling systems. the communication protocol for interface between these systems are required. Therefore the new communication protocol for railway signaling system is required. Generally, there are two verification method for new designed protocol in the industrial and academic fields. One is the laboratory testing method which is very popular and general technique. In our research the comparison between existing and new designed protocol for signaling is described and the verification test results are also represented. From these laboratory test, we are verified the conformance of new designed protocol. Another method is verified by formal method. The format verification method is widely used at safety-critical system design but this approach is nor popular at verification communication protocol. However it is very important to verify the safety of new designed protocol for railway signaling system because signaling systems are very safety-critical systems. So, the methodology for formal verification of designed protocol is also reviews in this paper.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.269-275
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• 2000

The railway signaling system consists of microcomputerized vital devices on board and ground, which are connected to one another by track circuits, and interlocking equipment for route control. Therefore it is important to validate the required functions of developed system and interface between developed signaling systems. To verify the conditions and functions of signaling logic, the laboratory prototype test bench, which consists of personal computers with software module and Ethernet LAN, will be developed. In this paper general design of signaling system test bench for high-speed rail is described and developed software module is presented.

• International Journal of Safety
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• 제10권2호
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• pp.27-31
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• 2011

As safety-related regulations for signaling systems are standardized to IEC 61508 and 62425, and others at the international level, safety activities and its verification are required. And also there is need to develop technologies for safety improvement to secure safety signaling systems in terms of technologies for safety activities on each life-cycle. In this paper it is reviewed the safety activity processes and technologies each steps of proposed processes respectively for railway signaling systems.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.358-362
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• 2004

Verification and testing are complementary techniques that are used to increase the level of confidence in the correct functioning of communication systems as prescribed by their specifications. This paper presents an experience of model checking for a formal railway signaling protocol specified in LTS (Labeled Transition System). This formal approach checks deadlock, livelock and reachability for the state and action to verify whether properties expressed in modal logic are true on specifications. We also propose a formal method for semi-automated test case generation for a railway signaling protocol described in I/O FSM (Input/Output Finite State Machine). This enables the generation of more complete and consistent test sequence for conformance testing. The above functions are implemented by C++ language and included within RSPVTE (Railway Signaling Protocol Verification and Testing Environment).

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.354-357
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• 2004

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 in the past. In this paper, new network-based protocol for Korean railway signaling has designed between CTC and SCADA system, and the overview of designed protocol is briefly represented. Using the informal method for specifying the communication protocol, a little ambiguity may be contained in the protocol. To clear the ambiguity contained in the designed protocol, we use LTS model to design the protocol for this interface link between CTC and SCADA, the LTS is an intermediate model for encoding the operational behavior of processes. And then, we verify automatically and formally the safety and the liveness properties through the model checking method. Especially, the modal ${\mu}$-calculus, which is a highly expressive method of temporal logic that has been applied to the model checking method. 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 in Korea.