철도제어시스템을 위한 높은 신뢰성을 갖는 제어시스템 구조 연구

조현정(Hyun-Jeong Jo),신경호(Kyung-Ho Shin),황종규(Jong-Gyu Hwang),임인택(In-Taek Lim),권혁빈(Hyeok-Bin Kwon) 대한전기학회 2020 전기학회논문지 P Vol.69 No.1

In the railway, signaling systems are located in the wayside and on-board as the very vital control system ensuring the safety operation of the train. Since a trivial failure of this signaling system can cause a fatal railway accident, the securement of high safety and availability of the signaling system is becoming a very important issue. In order to secure the high safety and availability of vital signaling system, efforts need to be made in many aspects of the hardware architecture, software and system lifecycle. Among of these, this paper focuses on the hardware architecture of railway signaling system. Currently, there are several hardware architectures applied to railway signaling systems, including the single, duplicated, and triple redundancy architectures. Single and duplicated redundancy architectures can cause fatal accidents because the whole system is affected when accident occur. For this reason, triple redundancy architecture has been the more popular for vital signaling systems. But this architecture has problems regarding its installation in the railway vehicle, as it occupies a large space and is intrinsically heavy in weight. We propose a noble fault-tolerant architecture for the vital railway signaling system that is triple redundancy-based, a cost-effective architecture that satisfies the installation conditions of space and weight.

철도신호분야의 CENELEC 규격과 다른 안전 규격들과의 관계 분석

조현정(Hyun-Jeong Jo),황종규(Jong-Gyu Hwang) 대한전기학회 2008 대한전기학회 학술대회 논문집 Vol.2008 No.7(초록집)

철도시스템 소프트웨어 변경영향 분석을 위한 자동화 도구 개발

조현정(Hyun-Jeong Jo),황종규(Jong-Gyu Hwang),김용규(Yong-Kyu Kim) 대한전기학회 2009 전기학회논문지 P Vol.58 No.2

Recent advances in computer technology have brought more dependence on software to railway systems. Hence, the safety assurance of the vital software running on the railway system is very critical task and yet, not many works have been done. While much efforts have been reported to improve electronic hardware's safety, not so much systematic approaches to evaluate software's safety. In this paper, we suggested an automated analysis tool for S/W change impact in railway system, and presented its result of implementation. The analysis items in the implemented tool had referred to the international standards in relation to the software for railway system, such as IEC 61508 and IEC 62279. In these international standards, 'change impact analysis' for railway system S/W has to be required mandatorily. The proposed tool can be utilized at the assessment stage and also the software development stage.

철도시스템 통신 안전성 확보를 위한 방법 제시 및 도구 구현

조현정(Hyun-Jeong Jo),황종규(Jong-Gyu Hwang),김용규(Yong-Kyu Kim) 대한전기학회 2010 전기학회논문지 P Vol.59 No.1

Safety-critical systems related to the railway communications are currently undergoing changes. Mechanical and electro-mechanical devices are being replaced by programmable electronics that are often controlled remotely via communication networks. Therefore designers and operators now not only have to contend with component failures and user errors, but also with the possibility that malicious entities are seeking to disrupt the services provided by theirs systems. Recognizing the safety-critical nature of the types of communications required in train control operations, the communications infrastructure will be required to meet a number of safety requirements such as system faults, user errors and the robustness in the presence of malicious attackers who are willing to take determined action to interfere in the correct operation of a system. In this paper, we proposed the safety strategies employed in the railway communications and a security mechanism for Korean railway communication system. Also, we presented the developed means for validation and determination of communication safety based on the proposed security mechanism in the railway system.

열차제어시스템을 위한 정형기법 적용 절차 및 템플릿 제안

조현정(Hyun-Jeong Jo),황종규(Jong-Gyu Hwang),윤용기(Yong-Ki Yoon) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.4

There is an emerging need for applying a formal method to develop the software that requires a high level of safety in safety-critical systems like railways. According, they are expanding the target for applying the formal method in developed countries for railways out of the country. It is surely necessary to plan on specific procedures and applications in order to apply such a formal method in domestic railway industry. Therefore, in this paper we propose the design templates so that the workers in the railway industry may use with ease the formal method having intricate and difficult characteristics on the basis of mathematics and logics.

Z와 Statechart에 의한 열차제어시스템 바이탈 소프트웨어 개발 방법 분석

趙賢庭(Hyun-Jeong Jo),黃宗奎(Jong-Gyu Hwang),尹用基(Yong-Ki Yoon) 대한전기학회 2008 전기학회논문지 P Vol.57 No.2

Recently, many critical control systems are developed using formal methods. When software applied to such systems is developed, the employment of formal methods in the software requirements specification and verification will provide increased assurance for such applications. Earlier error of overlooked requirement specification can be detected using formal specification method. Also the testing and full verification to examine all reachable states using model checking to undertake formal verification are able to be completed. In this paper, we propose an eclectic approach to incorporate Z(Zed) formal language and 'Statemate MAGNUM' which is formal method tools using Statechart for applying to the railway signaling systems.

철도시스템 소프트웨어 테스트 커버리지 자동화 도구 및 기준 분석

조현정(Jo, Hyun-Jeong),황종규(Hwang, Jong-Gyu),신승권(Shin, Seung-Kwon),오석문(Oh, Seok-Moon) 한국산학기술학회 2010 한국산학기술학회논문지 Vol.11 No.11

최근 컴퓨터시스템으로 전환되고 있는 철도시스템에서 소프트웨어에의 의존성이 급격히 증가함에 따라 임베 디드화된 철도시스템 소프트웨어 신뢰성과 안전성의 검증이 중요한 문제로 대두되기 시작했다. 이에 따라 철도 소프 트웨어 관련 국제표준에서도 각종 소프트웨어 테스트 및 검증활동을 요구하고 있으며, 이에 대응하여 본 논문에서는 철도시스템 소프트웨어 테스트 커버리지 자동화 도구 및 기준 분석과 개발 결과에 대해 제시하고 있다. 본 논문에서 는 철도시스템 소프트웨어 안전성 검증을 위한 정량적인 항목으로 매우 중요한 테스트 커버리지를 자동으로 측정할 수 있는 제어흐름 분석도구를 개발하였으며, 본 도구의 결과를 실제 철도 산업 현장에서 활용하기 위해 타분야 제시 기준 등을 분석하여 철도 소프트웨어 안전무결성레벨(SWSIL)에 따른 판단 기준을 제시하였다. 개발한 도구는 기존 해외 도구에 비해서 여러 테스트 커버리지를 효과적으로 측정할 수 있는 강점이 있으며, 실제 철도 현장에서 활용성 이 높아 철도 소프트웨어의 개발 및 테스트 기술 발전을 기대할 수 있다. 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.

철도시스템 소프트웨어를 위한 자동화된 데이터흐름 시험도구의 구현

조현정(Hyun-Jeong Jo),황종규(Jong-Gyu Hwang) 대한전자공학회 2010 대한전자공학회 학술대회 Vol.2010 No.6

열차제어시스템 안전성 확보를 위한 리스크 평가 방법 분석

조현정(Jo Hyun-Jeong),황종규(Hwang Jong-Gyu),윤용기(Yoon Yong-Ki) 한국철도학회 2006 한국철도학회 학술발표대회논문집 Vol.- No.-

Recently, failures of equipments are linked directly to extensive damages of human lives or financial losses from the increasing uses of train control equipments utilizing computers. Then safety activities have to progress for guaranteeing safety during the system life-cycle. In this paper, we examine the methods for risk analysis and assessment of safety activities and propose optimized one method for risk assessment. There are original risk assessment methods; risk graph and risk matrix method under the qualitative analysis, IRF(Individual Risk Formula) calculations and statistical calculations method under the quantitative analysis. Best-Practice(BP) risk analysis method is proposed for combining advantages of the qualitative and the quantitative analysis. In the comparison of risk graph and risk matrix method for safety estimation, BP method has no applications published up to now, but we can expect that this method will be utilized widely for the risk assessment due to various strong points.

심볼릭 수행 방법을 이용한 철도 소프트웨어 코드분석 도구제안

조현정(Hyun-Jeong Jo),황종규(Jong-Gyu Hwang),신덕호(Duck-Ho Shin) 대한전기학회 2016 전기학회논문지 P Vol.65 No.4

The railway 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 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 railway system was started to become influential as the important issue. Accordingly, various software test and validation activities are highly recommended in the international standards related railway software. In this paper, we presented a software coding analysis tool using symbolic execution for railway system, and presented its result of implementation.