Safety-critical systems in various industries such as transportation or nuclear energy have been paid more attention with the development of societies due to increased attachment of importance to the life of human, their property, and nature. While developing such systems, detailed availability and safety characteristics are to be taken into account in parallel with architectural design decisions such as synchronization between different computing units or real-time task management. For fulfilling top-level requirements in international standards, ambitious quantitative targets like 0.012 FIT for HW units are to be reached where the industry has difficulties to achieve it. In this paper, this problem is handled by proposing an augmented Markov model for diverse architectures that is superior to the formulas provided in the main safety standard IEC 61508 and previous studies. With the proposed method it is possible to cover all safety-relevant states, which leads to more accuracy and lower hazard rates helping to reach these ambitious quantitative targets. Besides, the reliability parameters are investigated and optimized to increase safety performance. Consequently, the proposed novel model including enhanced reliability parameters is used for an industry application, namely safety-critical computer used for unmanned metro and high-speed rail transportation. The result obtained by the proposed model is compared with the results obtained using state of art models in literature and using the formulas in IEC 61508. As domain independent references IEC 61508 and Markovian approach are used in the paper, this study is applicable to other safety critical areas such as automotive or avionic industry.

中文翻译：

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增强马尔可夫模型提高具有多种冗余架构的安全关键系统的危险率结果


随着社会的发展，人们对人类生命、财产和自然的重视程度不断提高，交通运输或核能等各个行业的安全关键系统受到越来越多的关注。在开发此类系统时，应与架构设计决策同时考虑详细的可用性和安全特性，例如不同计算单元之间的同步或实时任务管理。为了满足国际标准的顶级要求，在行业难以实现的领域，需要实现诸如硬件设备 0.012 FIT 等雄心勃勃的量化目标。在本文中，通过提出一种针对不同架构的增强马尔可夫模型来解决这个问题，该模型优于主要安全标准 IEC 61508 和之前的研究中提供的公式。通过所提出的方法，可以覆盖所有与安全相关的状态，从而提高准确性并降低危险率，有助于实现这些雄心勃勃的定量目标。此外，还对可靠性参数进行了研究和优化，以提高安全性能。因此，所提出的包括增强的可靠性参数的新模型用于工业应用，即用于无人地铁和高速轨道交通的安全关键计算机。将所提出的模型获得的结果与使用文献中最先进的模型和 IEC 61508 中的公式获得的结果进行比较。由于本文中使用了领域独立参考 IEC 61508 和马尔可夫方法，因此本研究适用于其他安全汽车或航空电子工业等关键领域。