Analysis of design parameters in SIL-4 safety-critical computer

Ahangari, Hamzeh; Ozkok, Yusuf Ibrahim; Yildirim, Asil; Say, Fatih; Atik, Funda; Öztürk, Özcan

doi:10.1109/ram.2017.7889787

Cited by 1 publication

(1 citation statement)

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“…Note that in Figure 7, since the failure in state (2) is undetected or hidden, the system seemingly works with two operational channels. Therefore, the system has similar behavior against DD failures in both state (1) and state (2). However, in fact the faulty channel is not counted as operational.…”

Section: Default Parametersmentioning

confidence: 99%

Analysis of Design Parameters in Safety-Critical Computers

Ahangari

Atik

Ozkok

et al. 2020

IEEE Trans. Emerg. Topics Comput.

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Nowadays, safety-critical computers are extensively used in many civil domains like transportation including railways, avionics, and automotive. In evaluating these safety critical systems, previous studies considered different metrics, but some of safety design parameters like failure diagnostic coverage (C) or common cause failure (CCF) ratio have not been seriously taken into account. Moreover, in some cases safety has not been compared with standard safety integrity levels (IEC-61508: SIL1-SIL4) or even have not met them. Most often, it is not very clear that which part of the system is the Achilles heel and how design can be improved to reach standard safety levels. Motivated by such design ambiguities, we aim to study the effect of various design parameters on safety in some prevalent safety configurations, namely, 1oo2 and 2oo3, where 1oo1 is also used as a reference. By employing Markov modeling, we analyzed the sensitivity of safety to important parameters including: failure rate of processing element, failure diagnostic coverage, CCF ratio, test and repair rates. This study aims to provide a deeper understanding on the influence of variation in design parameters over safety. Consequently, to meet appropriate safety integrity level, instead of improving some parts of a system blindly, it will be possible to make an informed decision on more relevant parameters.

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Section: Default Parametersmentioning

confidence: 99%