• Proceedings of the KSR Conference
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• 2007.05a
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• pp.987-992
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• 2007

Safety critical systems are those in which a failure can have serious and irreversible consequences. Nowadays digital technology has been rapidly applied to critical system such as railways, airplanes, nuclear power plants, vehicles. The main difference between analog system and digital system is that the software is the key component of the digital system. The digital system performs more varying and highly complex functions efficiently compared to the existing analog system because software can be flexibly designed and implemented. The flexible design make it difficult to predict the software failures. This paper reviews safety standard and criteria for safety critical system such as railway system and introduces the framework for the software lifecycle. The licensing procedure for the railway software is also reviewed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.9
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• pp.880-886
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• 2014

Many railway signalling functions have increasingly depended on computer software with recent development in computing technology, leading to evolution into more flexible and intelligent railway signalling system. Meanwhile, software programs are likely to have many errors and the cost incurred by such errors has increased. Especially, if fatal software error occurs during railway operation, it may result in loss of lives. So the software verification and validation have become more important. It is needed for software functional safety tool to support these, but most commercial tools depend on direct access to the system's memory, resulting in many difficulties in application. Owing to such difficulties and complexity, they are rarely used in railway signalling system software validation. In this study, a new testing tool for software functional testing through an external interface that can be easily used in functional testing of software was developed. Such testing tool allows development and analysis of test cases for black-box testing through analysis of actually used interface protocols, leading to increased user convenience.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4460-4467
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• 2010

Recent advances in computer technology have brought more dependence on software to railway systems and changed to computer systems. Hence, the reliability and safety assurance of the vital software running on the embedded railway system is going to tend toward very critical task. Accordingly, various software test and validation activities are highly recommended in the international standards related railway software. In this paper, we presented an automated analysis tool and standard for software testing coverage in railway system, and presented its result of implementation. We developed the control flow analysis tool estimating test coverage as an important quantitative item for software safety verification in railway software. Also, we proposed judgement standards due to railway S/W Safety Integrity Level(SWSIL) based on analysis of standards in any other field for utilizing developed tool widely at real railway industrial sites. This tool has more advantage of effective measuring various test coverages than other countries, so we can expect railway S/W development and testing technology of real railway industrial sites in Korea.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.968-973
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• 2007

The systems such as the railway control system, satellite control system and nuclear power plant control system are the safety critical systems because the failure of them could lead to risk significant events. These softwares of digital systems must follow the life cycle process from the beginning of software development to guarantee their safety and reliability. The NRC(Nuclear Regulatory Commission) Reg Guide of nuclear fields, the RTCA/DO-178B standard which is used to acquire the certification for software in industrial aero field in European Union and United State, the DEF STAN 00-55 standard for the safety of electronic weapon in England, the IEC 601-1-4 for medical equipment and the IEC 62279 for railway system recommended the development life cycle. This paper introduces the development process and compares each other. Also it indicates applicable development criteria for the software of systems related to railway fields and describes the detailed procedure of development criteria. We describe the procedure to make the software development criteria in nuclear filed. For the software development related to railways, the process from plan phase to maintenance phase must be satisfied. The safety and reliability is guaranteed through these standards.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1252-1253
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• 2011

The railway signaling system is being converted to the computer system from the existing mechanical device, and the dependency on software is being increased rapidly. Though the size and degree of complexity of software for railway signaling system are slower than the development speed of hardware, it is expected that the size will be grown bigger gradually and the degree of complexity will be increased also. Accordingly, the validation of reliability and safety of embedded software for train control system was started to become influential as the important issue. In this paper, we presented boundary value analysis tool for railway signaling system software, and presented its result of implementation.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.204-206
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• 2007

The portion of embedded software in railway signaling system is increased by the advance of computer and communication technology. And the safely requirements for railway system are standardized by int'l std., such as IEC 62278 and IEC 62279. According to these circumstances for software safety problems, we are deduced the testing items for software safety test and assessment for railway signaling. Testing tools used for embedded software are surveyed to find a feasible safety assessment architecture. And the architecture of automatic test tool is proposed to test the deduced safely testing items in this paper.

• Journal of the Korean Society for Railway
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• v.1 no.1 s.1
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• pp.10-19
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• 1998

Described in this paper is the software to design of a railway interlocking table, which describes the functional specifications of an interlocking device. Interlocking tables has been designed mainly based on personal expertise among signal engineers. However, this expertise needs to be analyzed with technical uniformity and integrated in an organized system. The proposed software is amount to the signal engineer's expertise, yet a generalization of interlocking reasoning. The algorithm is based on the train route setting principle, and is applicable in solving practical problems by computers. The software was evaluated through man-made and machine-made interlocking tables are compared. The evaluation results proves the software to be effective for computer control of the signaling system as interlocking system with a much improved safety.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.659-664
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• 2008

The Railroad Safety Act's regulation reads as follows. "The Minister of Construction and Transportation may qualify and authorize the product to guarantee performance and safety of parts, machine, and device used in Railway fields." Another regulation reads as follows."“The guidelines about targets, standards, and procedures of Quality and Authority in first provision are decided as Ministry of Construction and Transportation Decree." The software used in rail cars and facilities is considered as a railway product. Therefore, it is qualified and authorized for acquiring the safety of rail cars and facilities. The software businesses shall again a Quality and Authority for applying a software to the rail cars and facilities. This paper regulates some guidelines that are needed to develop a software. The procedures that a software developer performs are divided by plan, requirement, design, implementation, and maintenance. The procedures that a software verification person performs are classified by verification plan, requirement verification, design verification, implementation verification, testing verification, maintenance verification, and safety activity. The entire processes and detailed activities to develope and verify a software are described as new guidelines.

• Proceedings of the KSR Conference
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• 2000.05a
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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.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1201-1202
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• 2007

Safety critical systems are those in which a failure can have serious and irreversible consequences. Nowadays digital technology has been rapidly applied to critical system such as railways, airplanes, nuclear power plants, vehicles. The main difference between analog system and digital system is that the software is the key component of the digital system. The digital system performs more varying and highly complex functions efficiently compared to the existing analog system because software can be flexibly designed and implemented. The flexible design make it difficult to predict the software failures. This paper reviews safety standard and criteria for safety critical system such as railway system and introduces the framework for the software lifecycle. The licensing procedure for the railway software is also reviewed.