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- Askerdal, Örjan, 1973, et al.
(författare)
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A Control Theory Approach for Analyzing the Effects of Data Errors in Safety-Critical Control Systems
- 2002
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Ingår i: Pacific Rim International Symposium on Dependable Computing, 2002. Proceedings. 2002. - 0769518524 ; , s. 105-114
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Konferensbidrag (refereegranskat)abstract
- Computers are increasingly used for implementing controlalgorithms in safety-critical embedded applications, such asengine control, braking control and flight surfacecontrol. Addressing the consequent coupling of control performancewith computer related errors, this paper develops a composite computerdependability/control theory methodology for analyzing the effectsdata errors have on control system dependability. The effect is measured as theresulting control error (defined as the difference between the desired value ofa physical property andits actual value). We use maximum bounds on this measure as the criterion forcontrol system failure (i.e., if the control error exceeds a certain threshold,the system has failed).In this paper we a) present suitable models of computer faults for analysis of control level effects andrelated analysis methods, and b) apply traditional control theoryanalysis methods for understanding the effects of data errors onsystem dependability. An automobile slip-control brake-system is used as an example showing the viability of our approach.
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| 4. |
- Askerdal, Örjan, 1973
(författare)
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On Impact and Tolerance of Data Errors with Varied Duration in Microprocessors
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The evolution of high-performance and low-cost microprocessors has led to their almost pervasive usage in embedded systems such as automotive electronics, smart gadgets, communication devices, etc. These mass-market products, when deployed in safety-critical systems, require safe services albeit at low recurring costs. Moreover, as these systems often operate in harsh environments, faults will occur during system operation, and thus, must be handled safely, i.e., tolerated. This thesis investigates the efficiency of adding software-implemented fault tolerance techniques to commercial off-the-shelf (COTS) microprocessors. Specifically, the following problems are addressed: Which faults need to be tolerated considering the architecture, implementation and operational environments for COTS processors? Which software-implemented fault-tolerance techniques are effective and efficient to use? How can the efficiencies of such designs be evaluated? The main contribution of this thesis is the development of novel approaches for estimating the effects of data errors with varied duration, and for ascertaining the efficiency of applied fault-tolerance techniques. These approaches are based on identifying the characteristics that determine which effects data errors will have on the system. Then these characteristics can be varied at a high abstraction level and the effects observed. The first approach is based on response analysis methods for understanding the effects of data errors on control systems. The second is a VHDL simulation-based fault injection method, based on insertion of specific components (so-called saboteurs) for varying the characteristics. As most system development processes start at a high abstraction level, we expect our approaches to be applied early in the process, and be a useful complement to traditional post-design assessment approaches such as fault-injection.
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| 5. |
- Eklund, Ulrik, 1967, et al.
(författare)
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Experience of introducing reference architectures in the development of automotive electronic systems
- 2005
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Ingår i: International Conference on Software Engineering: Proceedings of the second international workshop on Software engineering for automotive systems. - 1595931287
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Konferensbidrag (refereegranskat)abstract
- The requirements on increasing functionality, quality, and, customisation, while reducing cost has lead to the introduction of an architecture centred development process for electronic systems at Volvo Cars. This process enables better control of system integration and achieving non-functional requirements, such as reusability, understandability, etc. The result of the process is a reference architecture that includes strategies for implementing the balanced requirements, architectural views that provide means for reasoning about all the concerns of all stakeholders, and a top-level design of the architecturally significant parts. The reference architecture guides the design of several projects, and thus, cost is optimised accordingly. The main contribution of this paper is that we present experiences from introducing the architecture centred process. The main conclusions are that disseminating and maintaining the reference architecture actually require more resources than developing it. Furthermore, experience shows it is difficult to create an architecture that enables a lot of different variants that is also strategically useable in the long term.
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| 6. |
- Mohamad, Mazen, 1984, et al.
(författare)
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Asset-driven Security Assurance Cases with Built-in Quality Assurance
- 2021
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Ingår i: 2021 IEEE/ACM 2nd International Workshop on Engineering and Cybersecurity of Critical Systems (EnCyCriS 2021). - 9781665445535 ; , s. 29-36
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Konferensbidrag (refereegranskat)abstract
- Security Assurance Cases (SAC) are structured arguments and evidence bodies used to reason about the security of a certain system. SACs are gaining focus in the automotive domain as the needs for security assurance are growing. In this study, we present an approach for creating SAC. The approach is inspired by the upcoming security standards ISO/SAE-21434 as well as the internal needs of automotive Original Equipment Manufacturers (OEMs). We created the approach by extracting relevant requirements from ISO/SAE-21434 and illustrated it using an example case of the headlamp items provided in the standard. We found that the approach is applicable and helps to satisfy the requirements for security assurance in the standard as well as the internal compliance needs in an automotive OEM.
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| 7. |
- Mohamad, Mazen, 1984, et al.
(författare)
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Assurance Cases for Road Vehicles: an Industry Perspective
- 2020
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Ingår i: ARES '20: Proceedings of the 15th International Conference on Availability, Reliability and Security.
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Konferensbidrag (refereegranskat)abstract
- Assurance cases are structured arguments that are commonly used to reason about the safety of a product or service. Currently, there is an ongoing push towards using assurance cases for also cybersecurity, especially in safety critical domains, like automotive. While the industry is faced with the challenge of defining a sound methodology to build security assurance cases, the state of the art is rather immature. Therefore, we have conducted a thorough investigation of the (external) constraints and (internal) needs that security assurance cases have to satisfy when used in the automotive industry. This has been done in the context of two large automotive companies. The end result is a set of recommendations that automotive companies can apply in order to define security assurance cases that are (i) aligned with the constraints imposed by the existing and upcoming standards and regulations and (ii) harmonized with the internal product development processes and organizational practices. We expect the results to be also of interest for product companies in other safety critical domains, like healthcare, transportation, and so on.
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