Browsing by Subject "Safety engineering"
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Item Open Access Analysis of design parameters in SIL-4 safety-critical computer(IEEE, 2017-01) Ahangari, Hamzeh; Özkök, Y. I.; Yıldırım, A.; Say, F.; Atik, Funda; Öztürk, ÖzcanNowadays, Safety-critical computers are extensively used in may civil domains like transportation including railways, avionics and automotive. We noticed that in design of some previous works, some critical safety design parameters like failure diagnostic coverage (DC) 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 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: 1oo2 and 2oo3. 1oo1 is also used as a reference. By employing Markov modeling, sensitivity of safety to each of the following critical design parameters is analyzed: failure rate of processing element, failure diagnostics coverage, common cause failures and repair rates. This study gives a deeper sense regarding influence of variation in design parameters over safety. Consequently, to meet appropriate safety integrity level, instead of improving some system parts blindly, it will be possible to make an informed decision on more relevant parameters. © 2017 IEEE.Item Open Access Architecture framework for software safety(Springer, 2014-09) Gürbüz, Havva Gülay; Pala Er, N.; Tekinerdoğan, BedirCurrently, an increasing number of systems are controlled by soft- ware and rely on the correct operation of software. In this context, a safety- critical system is defined as a system in which malfunctioning software could result in death, injury or damage to environment. To mitigate these serious risks, the architecture of safety-critical systems needs to be carefully designed and analyzed. A common practice for modeling software architecture is the adoption of software architecture viewpoints to model the architecture for par- ticular stakeholders and concerns. Existing architecture viewpoints tend to be general purpose and do not explicitly focus on safety concerns in particular. To provide a complementary and dedicated support for designing safety critical systems, we propose an architecture framework for software safety. The archi- tecture framework is based on a metamodel that has been developed after a tho- rough domain analysis. The framework includes three coherent viewpoints, each of which addressing an important concern. The application of the view- points is illustrated for an industrial case of safety-critical avionics control computer system. © Springer International Publishing Switzerland 2014.Item Open Access An automotive vehicle dynamics prototyping platform based on a remote control model car(2013) Solmaz, S.; Coşkun, TürkerThe use of a modified remote control (RC) model car as a vehicle dynamics testing and development platform is detailed. Vehicle dynamics testing is an important aspect of automotive engineering and it plays a key role during the design and tuning of active safety control systems. Considering the fact that such tests are conducted at great expense, scaled model cars can potentially be used to help with the process to reduce the costs. With this view, we instrument and develop a standard electric RC model car into a vehicle dynamics testing platform. We then implement 2 representative active safety control applications based on this platform, namely an antilock brake system using open-loop pulse brake control and a roll-over prevention system utilizing lateral acceleration feedback. Both applications are presented with sensor measurements and the effectiveness of the suggested control algorithms are demonstrated. © TÜBİTAK.