| 1. |
- Nagaraja, Ch., et al.
(författare)
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Opening remarks
- 2016
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Konferensbidrag (refereegranskat)
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| 2. |
- Baumgart, S., et al.
(författare)
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Variability management in product lines of safety critical embedded systems
- 2014
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Ingår i: International Conference on Embedded Systems, ICES 2014. - 9781479950263 ; , s. 98-103
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Konferensbidrag (refereegranskat)abstract
- The product line engineering approach is a promising concept to identify and manage reuse in a structured and efficient way and is even applied for the development of safety critical embedded systems. Managing the complexity of variability and addressing functional safety at the same time is challenging and is not yet solved. Variability management is an enabler to both establish traceability and making necessary information visible for safety engineers. We identify a set of requirements for such a method and evaluate existing variability management methods. We apply the most promising method to an industrial case and study its suitability for developing safety critical product family members. This study provides positive feedback on the potential of the model-based method PLUS in supporting the development of functional safety critical embedded systems in product lines. As a result of our analysis we suggest potential improvements for it.
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| 3. |
- Colaco, L., et al.
(författare)
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mcDVFS : cycle conserving DVFS scheduler for multi-core mixed criticality systems
- 2023
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Ingår i: International Journal of Parallel, Emergent and Distributed Systems. - : Taylor and Francis Ltd.. - 1744-5760 .- 1744-5779.
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Tidskriftsartikel (refereegranskat)abstract
- Multi-core architectures have grown to be a popular choice for deploying Mixed Criticality Systems (MCS). The focus of research in MCS has been to provide timing assurances for jobs with different criticality levels. Due to their significant processing demands and energy-aware/constrained nature, energy conservation in these systems is becoming mandatory. This article presents, mcDVFS, an energy management technique based on Dynamic-Voltage-and-Frequency-Scaling for multi-core MCS. mcDVFS achieves significant energy reduction while maintaining timing guarantees. It also prioritizes quality of service whenever feasible. Extensive experimental simulations show energy savings of ≈ 52% and 34% when compared to EDF-VD and EDF-VD with QoS.
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| 4. |
- Colaco, L., et al.
(författare)
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Task models for mixed criticality systems – a review
- 2023
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Ingår i: International Journal of Critical Computer-Based Systems. - : Inderscience Publishers. - 1757-8779 .- 1757-8787. ; 10:4, s. 287-329
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Tidskriftsartikel (refereegranskat)abstract
- The past decade has seen tremendous interest in mixed criticality systems research due to its exponential growth with inherent challenges of effective resource utilisation and isolation. The pervasiveness of these systems along with their certification needs, prompt for suitable task models to perform the required analysis. Extensive usage scenarios and strict certification requirements have spawned a broad spectrum of research and evolved into several task models. In this work, a thematic survey of task models for both uni-core and multi-core mixed criticality systems is carried out. The work categorises task models based on attributes such as resources, quality of service, operating system overheads, energy, fault tolerance and parallel processing. After synthesising the state-of-the-art, the work summarises task models by providing a visual aid and a ready reckoner with traceability to mixed criticality challenges. This work serves as a quintessential reference manual for researchers and academicians in the mixed criticality domain.
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| 5. |
- Govardhan Rao, S. B., et al.
(författare)
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A Systematic Review of β-factor Models in the Quantification of Common Cause Failures
- 2023
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Ingår i: Proc. - Euromicro Conf. Softw. Eng. Adv. Appl., SEAA. - : Institute of Electrical and Electronics Engineers Inc.. - 9798350342352 ; , s. 262-269
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Konferensbidrag (refereegranskat)abstract
- Safety systems, i.e., systems whose malfunction can result in catastrophic consequences, are usually designed with redundancy in mind to reach high levels of reliability. However, Common Cause Failures (CCF), i.e., single failure events affecting multiple components or functions in a system, can threaten the desired reliability. To solve this problem, practitioners must use proven methods, such as those recommended by standards, to support CCF quantification. In particular, the β-factor model has become the de-facto model since the safety standard IEC 61508 considers it. As such standard applies to all industries, practitioners must figure out the industrial-specific implementation procedures. In this paper, we conducted a systematic literature review to understand how the β-factor model has been used in practice. As a result, we found 20 different models, which are industry/project-specific extensions of the first β-factor model proposed for the nuclear sector. We further classified those models by considering how the β-factor is estimated, and the level of redundancy support. Tool support for the models and their industrial use are also outlined. Finally, we present a discussion that covers the implication of our findings. Our study targets practitioners and researchers interested in using current β-factor models or evolving new ones for specific project needs.
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| 6. |
- Karagiannis, V., et al.
(författare)
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Addressing the node discovery problem in fog computing
- 2020
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Ingår i: OpenAccess Series in Informatics. - : Schloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing. - 9783959771443
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Konferensbidrag (refereegranskat)abstract
- In recent years, the Internet of Things (IoT) has gained a lot of attention due to connecting various sensor devices with the cloud, in order to enable smart applications such as: smart traffic management, smart houses, and smart grids, among others. Due to the growing popularity of the IoT, the number of Internet-connected devices has increased significantly. As a result, these devices generate a huge amount of network traffic which may lead to bottlenecks, and eventually increase the communication latency with the cloud. To cope with such issues, a new computing paradigm has emerged, namely: fog computing. Fog computing enables computing that spans from the cloud to the edge of the network in order to distribute the computations of the IoT data, and to reduce the communication latency. However, fog computing is still in its infancy, and there are still related open problems. In this paper, we focus on the node discovery problem, i.e., how to add new compute nodes to a fog computing system. Moreover, we discuss how addressing this problem can have a positive impact on various aspects of fog computing, such as fault tolerance, resource heterogeneity, proximity awareness, and scalability. Finally, based on the experimental results that we produce by simulating various distributed compute nodes, we show how addressing the node discovery problem can improve the fault tolerance of a fog computing system. © Vasileios Karagiannis, Nitin Desai, Stefan Schulte, and Sasikumar Punnekkat; licensed under Creative Commons License CC-BY 2nd Workshop on Fog Computing and the IoT (Fog-IoT 2020).
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| 7. |
- Nair, A. S., et al.
(författare)
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CAMP : a hierarchical cache architecture for multi-core mixed criticality processors
- 2024
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Ingår i: International Journal of Parallel, Emergent and Distributed Systems. - : Taylor and Francis Ltd.. - 1744-5760 .- 1744-5779.
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Tidskriftsartikel (refereegranskat)abstract
- CAMP proposes a hierarchical cache subsystem for multi-core mixed criticality processors, focusing on ensuring worst-case execution time (WCET) predictability in automotive applications. It incorporates criticality-aware locked L1 and L2 caches, reconfigurable at mode change intervals, along with criticality-aware last level cache partitioning. Evaluation using CACOSIM, Moola Multicore simulator, and CACTI simulation tools confirms the suitability of CAMP for keeping high-criticality jobs within timing budgets. A practical case study involving an automotive wake-up controller using the sniper v7.2 architecture simulator further validates its usability in real-world mixed criticality applications. CAMP presents a promising cache architecture for optimized multi-core mixed criticality systems.
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| 8. |
- Nair, A. S., et al.
(författare)
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CLAMP : Criticality Aware Coherency Protocol for Locked Multi-level Caches in Multi-core Processors
- 2023
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Ingår i: Lect. Notes Networks Syst.. - : Springer Science and Business Media Deutschland GmbH. - 9789819904822 ; , s. 371-381
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Konferensbidrag (refereegranskat)abstract
- Cyber-physical systems that combine sensing, computing, control and networking with physical items and infrastructure, such as automotive, avionics and robotics, are rapidly becoming mixed criticality systems (MCS). The increasing expectations for computing ability and predictable temporal behaviour of these systems necessitate substantial enhancements in their memory subsystem architecture. The use of locked caches to have predictable execution time is one such optimization. There is no comprehensive method in order to manage coherency in locked caches in any of the current cache coherence protocols like MOESI. CLAMP—A criticality aware coherency protocol for locked multi-level caches in multi-core processors is an updated variant of MOESI and as an extension of MOESIL, to improve the data consistency of locked caches. The work CLAMP proposes an improvised locked cache coherence protocol for multiple levels of cache in multi-core MCS, whereas MOESIL is restricted to two-level cache architecture. Experiments using real-time benchmark programs on CACOSIM reveal an average cache miss rate reduction of 18% for high-criticality jobs.
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| 9. |
- Pop, P., et al.
(författare)
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The FORA Fog Computing Platform for Industrial IoT
- 2021
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Ingår i: Information Systems. - : Elsevier Ltd. - 0306-4379 .- 1873-6076. ; 98
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Tidskriftsartikel (refereegranskat)abstract
- Industry 4.0 will only become a reality through the convergence of Operational and Information Technologies (OT & IT), which use different computation and communication technologies. Cloud Computing cannot be used for OT involving industrial applications, since it cannot guarantee stringent non-functional requirements, e.g., dependability, trustworthiness and timeliness. Instead, a new computing paradigm, called Fog Computing, is envisioned as an architectural means to realize the IT/OT convergence. In this paper we propose a Fog Computing Platform (FCP) reference architecture targeting Industrial IoT applications. The FCP is based on: deterministic virtualization that reduces the effort required for safety and security assurance; middleware for supporting both critical control and dynamic Fog applications; deterministic networking and interoperability, using open standards such as IEEE 802.1 Time-Sensitive Networking (TSN) and OPC Unified Architecture (OPC UA); mechanisms for resource management and orchestration; and services for security, fault tolerance and distributed machine learning. We propose a methodology for the definition and the evaluation of the reference architecture. We use the Architecture Analysis Design Language (AADL) to model the FCP reference architecture, and a set of industrial use cases to evaluate its suitability for the Industrial IoT area.
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| 10. |
- Shah, M. B. N., et al.
(författare)
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Error Handling Algorithm and Probabilistic Analysis Under Fault for CAN-Based Steer-by-Wire System
- 2016
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Ingår i: IEEE Transactions on Industrial Informatics. - 1551-3203 .- 1941-0050. ; 12:3, s. 1017-1034
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes an efficient way to handle fault in controller area network (CAN)-based networked control system (NCS). A fault in a bus line of CAN will induce a data error which will result in data dropout or time delay, and subsequently may lead to performance degradation or system instability. A strategy to handle fault occurrence in CAN bus is proposed to properly analyze the effect of the fault to CAN-based NCS performance. The fault occurrences are modeled based on fault interarrival time, fault bursts' duration, and Poisson law. Using fault and messages' attributes, response time analysis (RTA) is performed and the probability of control message missing its deadline is calculated. Utilizing the new error handling algorithm to replace the native error handling of CAN, the probability of a control message missing its deadline can be translated into the probability of data dropout for control message. This methodology is evaluated using steer-by-wire system of vehicle to analyze the effect of fault occurrences in CAN. It is found that the proposed error handling mechanism has resulted in better NCS performance and the range of data dropout probability for control message also could be obtained, which serves as crucial input for NCS controller design.
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