Comparing Software Safety Standards EUROCAE ED-153 and IEC 61508

Author(s):  
P.B. Ladkin
2020 ◽  
pp. 002029401988747
Author(s):  
Nadir Subasi ◽  
Ufuk Guner ◽  
Ilker Ustoglu

Safety-critical systems are widely used in many sectors to prevent fatal accidents and prevent loss of life, damage of property, or deterioration of the environment. Implementation of software safety standards as part of the development of safety-critical software is generally considered an essential element of any safety program. Therefore, it has become more critical to produce highly reliable software to meet the safety requirements established by functional safety standards, such as IEC 61508, ISO 26262, and EN 50128. IEC 61508 supports well-known safety mechanisms such as design diversity like N-version (multi-version) programming. N-version (multi-version) programming is a method where multiple functionally equivalent programs are independently developed from the same software specifications. N-version (multi-version) programming is particularly an effective approach to increase the quality of software in a safety-critical system. In this paper, one of the well-known and widely used algorithms in the field of N-version (multi-version) programming, the majority voting algorithm, has been modified with an online stability checker where the decisions of the voter are judged against the stability of the underlying system. The plant where all the theoretical results are implemented is a tilt-rotor system with the proposed N-version (multi-version) programming–based controller. The experimental results show that the modified majority voter-based N-version (multi-version) programming controller provides more reliable control of the plant.


Author(s):  
SHIGERU YAMADA ◽  
TAKAHIRO NISHIKAWA

Reliability and safety for hardware in computer systems have been sufficiently studied in recent years. On the other hand, a safety-related system (SRS) for software has not been assured with the proper method of calculating the software safety integrity level (SIL) in the functional safety standards, which is currently determined only by the number of development methods applied to practical safety-related system (SRSs). In this paper, we discuss quantitative assessment for it by applying quantitative measures based on software reliability growth models (SRGMs) that have been widely and successfully applied to practical software quality management activities. Based on a nonhomogeneous Poisson process (NHPP), the plausible methods of calculating software SIL in the functional safety standard are proposed. Further, we discuss the quantitative method for assuring software SIL based on the optimal release policies with the test cost during testing-environment and the risk cost after the software products will be released.


Computer ◽  
1993 ◽  
Vol 26 (1) ◽  
pp. 88-89 ◽  
Author(s):  
P.V. Bhansali

Author(s):  
Shinji Inoue ◽  
Takaji Fujiwara ◽  
Shigeru Yamada

Quantitative and analytical safety assessment methods of E/E/PE safety-related software systems based on the SIL defined by IEC 61508 have been proposed. IEC 61508 does not provide us with quantitative and analytical methods for safety assessment of the software. Our methods give us quantitative information on safety measures for deciding the safety integrity level and testing time duration for achieving certain safety integrity level of E/E/PE software, respectively. Our stochastic modeling approaches are based on software reliability modeling and software reliability assessment techniques. Numerical examples for our methods have been shown for explaining how to use our software safety assessment approaches conforming IEC 61508.


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