| 1. |
- Barbosa, Raul, 1981, et al.
(author)
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Shared data from a study of measurement uncertainty in fault injection
- 2010
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In: Proceedings - International Conference on Distributed Computing Systems. - 9780769540795 ; , s. 284-285
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Conference paper (other academic/artistic)abstract
- Experimental dependability studies usually produce an amount of data substantially greater than what can be presented in a research paper or a technical report. For this reason, authors condensate the results into more succinct forms that allow them to convey their message. Since a large amount of the original data is left unexplored, sharing it allows other teams to discover additional facts (as well as to compare the results to other studies). In a previous paper, we investigated sources of uncertainty in measurement results obtained using three different fault injection techniques. The resulting experimental data was shared in the AMBER raw data repository. This paper gives an overview of the study and makes an attempt at further exploring the shared data.
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| 2. |
- Islam, Md Mafijul, et al.
(author)
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Towards benchmarking of functional safety in the automotive industry
- 2013
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In: Lecture Notes in Computr Science. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. - 9783642387883 ; , s. 111-125
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Conference paper (peer-reviewed)abstract
- Functional safety is becoming increasingly important in the automotive industry to deal with the growing reliance on the electrical and/or electronic (E/E) systems and the associated complexities. The introduction of ISO 26262, a new standard for functional safety in road vehicles, has made it even more important to adopt a systematic approach of evaluating functional safety. However, standard assessment methods of benchmarking functional safety of automotive systems are not available as of today. This is where the BeSafe (Benchmarking of Functional Safety) project comes into the picture. BeSafe project aims to lay the foundation for benchmarking functional safety of automotive E/E systems. In this paper, we present a brief overview of the project along with the benchmark targets that we have identified as relevant for the automotive industry, assuming three abstraction layers (model, software, hardware). We then define and discuss a set of benchmark measures. Next, we propose a benchmark framework encompassing fault/error models, methods and the required tool support. This paper primarily focuses on functional safety benchmarking from the Safety Element out of Context (SEooC) viewpoint. Finally, we present some preliminary results and highlight potential future works.
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| 3. |
- Skarin, Daniel, 1979, et al.
(author)
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Comparing and validating measurements of dependability attributes
- 2010
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In: EDCC-8 - Proceedings of the 8th European Dependable Computing Conference. - 9780769540078 ; , s. 3-12
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Conference paper (other academic/artistic)abstract
- This paper investigates sources of uncertainty in measurement results obtained using three different fault injection techniques. Two software-implemented and one test port-based technique are characterized and compared. The three techniques can be used to inject the same faults, which are defined in a shared database. Due to the uncertainties associated with the techniques, which we identify and discuss, the results of injecting a given fault may differ to some extent. The paper analyzes the results of using the three techniques to inject faults into two experimental targets: a brake-by-wire controller and a partitioning operating system. The objective of the experiments is to determine whether the results of the different techniques are metrologically compatible and, consequently, meaningful when disseminated and compared. Our observations indicate that, even though the outcome of many individual experiments is affected by uncertainties, the three techniques produce similar average results over a large number of experiments. © 2010 IEEE.
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| 4. |
- Skarin, Daniel, 1979, et al.
(author)
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Evaluation of Low-Cost Detection and Recovery of Soft Errors in an ABS controller
- 2009
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In: Proceedings of the 2009 IEEE Workshop on Silicon Errors in Logic - System Effects (SELSE 5).
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Conference paper (peer-reviewed)abstract
- This paper presents experimental results on a prototype brake controller's susceptibility to soft errors. We have developed a set of simple software-implemented error detection and recovery mechanisms which, in combination with hardware exceptions, aim at preventing soft errors from causing critical braking failures. To evaluate the effectiveness of these mechanisms, we injected roughly 60 000 single bit-flips into CPU registers and data memory of a MPC565 microcontroller running the brake controller program. The results show that the combined mechanisms effectively prevented critical braking failures; only three errors caused a critical behavior of the controller. As much as 69.0% of the errors escaped detection, but these errors had only a minor impact on the brake performance. Only 26.6% of the injected errors were detected and subsequently recovered from by the software. Of these were 91.5% detected by hardware exceptions and 8.5% by the software mechanisms. Despite all errors were injected into registers holding "live" data, as much as 46.9% were masked by the program and did not in any way affect the produced brake commands.
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| 5. |
- Skarin, Daniel, 1979, et al.
(author)
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GOOFI-2: A tool for experimental dependability assessment
- 2010
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In: Proceedings of the International Conference on Dependable Systems and Networks; 2010 IEEE/IFIP International Conference on Dependable Systems and Networks, DSN 2010; Chicago, IL; 28 June 2010 through 1 July 2010. - 9781424475018 ; , s. 557-562
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Conference paper (peer-reviewed)abstract
- This paper presents GOOFI-2, a comprehensive fault injection tool for experimental dependability assessment of embedded systems. The tool includes a large number of extensions and improvements over its predecessor, GOOFI-2. These include support for three widely used fault injection techniques, two target processors, and a variety of new features for storing, disseminating and analyzing experimental data. We report on our experiences and lessons learned from the use and development of GOOFI-2. In particular, we compare and discuss properties of three fault injection techniques: Nexus-based, exception-based and instrumentation-based injection. The comparison relies on several sets of experiments with two target processors, Freescale's MPC565 and MPC5554. © 2010 IEEE.
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| 6. |
- Skarin, Daniel, 1979, et al.
(author)
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Impact of Soft Errors in a Brake-by-Wire System
- 2007
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In: Proceedings of the 2007 IEEE Workshop on Silicon Errors in Logic - System Effects (SELSE 3).
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Conference paper (peer-reviewed)abstract
- This paper presents an experimental evaluation of the impact of soft errors in a brake-by-wire system for road vehicles. Our goal is to assess the risk that soft errors will cause the brake system to produce undetected dangerous outputs. To this end, we injected single bit-flips in the CPU registers and the main memory of a MPC565 microcontroller running a brake controller program. For each injected bit-flip, we recorded the outputs to the brake actuator for more than one thousand control cycles. The results show that 24% (769 of 3149) of the bit-flips injected in the CPU registers resulted in undetected erroneous outputs. Of these, 24% (188 of 769) resulted in dangerous outputs. The corresponding numbers for bit-flips injected in the main memory are 35% (985 of 2831), and 8.1% (80 of 985), respectively. Despite all injections were made into "live" registers or memory elements, 40% of the register bit-flips and 51% of the memory bit-flips had no impact at all on the output.
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| 7. |
- Skarin, Daniel, 1979
(author)
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On Fault Injection-Based Assessment of Safety-Critical Systems
- 2010
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Doctoral thesis (other academic/artistic)abstract
- This thesis deals with techniques for designing and evaluating error detection and recovery mechanisms for computer systems. For the assessment of such systems, we describe a comprehensive fault injection tool that is capable of emulating the effects of hardware errors in microprocessors. The tool integrates three known fault injection techniques into a unified framework, and is easy to extend with support for new techniques and target systems.The techniques included in the tool have different characteristics with respect to observability and temporal intrusiveness, but can nevertheless be used to inject the exact same faults. However, due to uncertainties associated with each technique, which we identify and discuss, the results of injecting a given fault may differ to some extent. We therefore perform an analysis to determine if results obtained with the three techniques are metrologically compatible, and thereby meaningful for dissemination and comparison.To illustrate the practical usage of the tool, we describe an evaluation-driven design process for development of software-implemented fault tolerance. We used this process to develop two software mechanisms for a prototype brake controller. The mechanisms were specifically designed to prevent transient hardware errors from causing critical system failures. The effectiveness of the software mechanisms were evaluated with extensive fault injection experiments. The results show that these mechanisms can effectively reduce the probability of critical brake controller failures.
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| 8. |
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| 9. |
- Skarin, Daniel, 1979, et al.
(author)
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Software Mechanisms for Tolerating Soft Errors in an Automotive Brake-Controller
- 2009
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In: Proceedings Supplemental Volume of the 2009 IEEE/IFIP Conference on Dependable Systems and Networks (DSN 2009). - 9781424444212 ; , s. D34-D38
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Conference paper (peer-reviewed)abstract
- This paper describes the design and evaluation of two software implemented error detection and system recovery mechanisms that protect a prototype brake-by-wire controller from soft errors. We used an evaluation driven design process to develop the software mechanisms, which are specifically designed to prevent soft errors from causing critical failures in the brake controller. The design process involves 1) identifying vulnerable parts of the brake controller, 2) designing and verifying software mechanisms for error detection and recovery, and 3) performing an extensive evaluation of the proposed mechanisms. Results from error injection experiments in the last step show that our simple software mechanisms, combined with hardware exceptions for error detection, can effectively reduce the number of critical failures caused by soft errors in the brake controller.
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| 10. |
- Skarin, Daniel, 1979
(author)
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Techniques for Tolerating Soft Errors in Brake-by-Wire Systems
- 2008
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Licentiate thesis (other academic/artistic)abstract
- This thesis addresses the problem of tolerating soft errors in brake-by-wire systems. Soft errors are caused by ionizing particles and manifest themselves as bit-flips in memory registers, latches, and flip-flops. As transistors are shrunk to sustain Moore's law, the frequency of such radiation-induced faults increases. The overall goal of the thesis is to design and evaluate cost-efficient techniques to tolerate soft errors in control systems.To emulate the effects of soft errors, we inject single bit-flips into the registers and the main memory of a microcontroller running a prototype brake controller. We first evaluate a version of the brake controller in which hardware exceptions are the only means for detecting errors. These experiments show that although many of the injected errors are masked by the brake controller program, a non-negligible proportion of the errors caused the controller to produce erroneous outputs to the brake actuator.We designed two software implemented mechanisms for detecting and recovering soft errors in the brake controller. These mechanisms protect the stack pointer and the brake controller's integrator state. Using a second error injection campaign, we evaluate the effectiveness of these mechanisms. Results from this campaign show that the software mechanisms reduced the proportion of errors causing critical controller significantly.
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