| 1. |
- Barzegaran, Mohammadreza, et al.
(författare)
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Electric drives as fog nodes in a fog computing-based industrial use case
- 2021
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Ingår i: The Journal of Engineering. - : WILEY. - 2051-3305. ; 2021:12, s. 745-761
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Tidskriftsartikel (refereegranskat)abstract
- Electric drives, which are a main component in industrial applications, control electric motors and record vital information about their respective industrial processes. The development of electric drives as Fog nodes within a fog computing platform (FCP) leads to new abilities such as programmability, analytics, and connectivity, increasing their value. In this study, the FORA FCP reference architecture is used to implement electric drives as Fog nodes, which is called "fogification". The fogified drive architecture and its components are designed using Architecture Analysis and Design Language (AADL). The design process was driven by the high-level requirements that the authors elicited. Both the fogified drive architecture and the current drive architecture are used to implement a self baggage drop system in which electric drives are the key components. The fog-based design was then evaluated using several key performance indicators (KPIs), which reveal its advantages over the current drive architecture. The evaluation results show that safety-related isolation is enabled with only 9% overhead on the total Fog node utilization, control applications are virtualized with zero input-output jitter, the hardware cost is reduced by 44%, and machine learning at the edge is performed without interrupting the main drive functionalities and with an average 85% accuracy. The conclusion is that the fog-based design can successfully implement the required electric drive functionalities and can also enable innovative uses needed for realizing the vision of Industry 4.0.
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| 2. |
- Barzegaran, Mohammadreza, et al.
(författare)
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Fogification of Electric Drives: An industrial use case
- 2020
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Ingår i: The 25th International Conference on Emerging Technologies and Factory Automation ETFA2020.
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Konferensbidrag (refereegranskat)abstract
- Electric drives are used to control electric motors, which are pervasive in industrial applications. In this paper we propose enhancing the electric drives to fulfil the role of fog nodes within a Fog Computing Platform (FCP). Fog Computing is envisioned as a realization of future distributed architectures in Industry 4.0. We identify the system-level requirements of such an FCP, including requirements that are extracted from the current architecture of drives, which we consider as a baseline. These requirements are then used to design a system-level architecture, which we model using the Architecture Analysis & Design Language (AADL). We identify the “technology bricks” (components such as hardware, software, middleware, services, methods and tools) needed to implement the FCP. The proposed fog-based architecture is then used to implement a Conveyor Belt industrial use case. We evaluate the resulting use case on several aspects, demonstrating the usefulness of the proposed fogbased approach. By developing the electric drives as fog nodes, new offerings like programmability, analytics and connectivity to customer Clouds are expected to increase the added value. Increased flexibility allows drives to assume a larger role in industrial and domestic control systems, instrumenting thus also legacy systems by using drives as the data source.
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| 3. |
- Desai, Nitin, 1986-, et al.
(författare)
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A Topology-specific Tight Worst-case Analysis of Strict Priority Traffic in Real-time Systems
- 2023
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Ingår i: IEEE Int. Conf. Emerging Technol. Factory Autom., ETFA. - : Institute of Electrical and Electronics Engineers Inc.. - 9798350339918
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Konferensbidrag (refereegranskat)abstract
- Tight end-to-end worst-case delay bounds for periodic traffic streams are essential for time sensitive networks. In this paper, we provide an algorithm to compute a tight (and accurate) end-to-end worst-case bound by considering distinct topological patterns and the manner in which streams enter and leave switches. This refined analysis uses non-preemptive, strict-priority arbitration mechanism commonly deployed in Ethernet switches. Compared to the state-of-the-art that considers all higher and equal priority interference as contributing to the worst-case bound, we present an analytical approach for computing a tighter worst-case delay bound and prove through discrete event simulations that only a certain number of equal-priority interference streams can actually affect the worst-case case. Our results enable efficient resource allocation and have implications for online re-configuration mechanisms for time-sensitive factory communication systems.
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| 4. |
- Desai, Nitin, 1986-
(författare)
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Designing safe and adaptive time-critical fog-based systems
- 2021
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Safety-critical systems in industrial automation, avionics, or automotive domains demand correct, timely and predictable performance under all(including faulty) operating conditions. Fault-tolerance plays an important role in ensuring seamless system function even in the presence of failures. Typically such systems run hard real-time applications, and hence timing violations can result in hazards. Fog computing is an adaptive paradigm which distributes computation and communication along the cloud-IoT continuum to reduce communication latencies, making it more conducive to execute real-time applications. This requires enhancements to the network connecting various sub-systems to support timely delivery of safety-critical messages. Traditionally safety-critical systems are designed offline and are not re-configured during runtime. The inherent adaptive properties of fog computing systems make it susceptible to timeliness violations and can be a hindrance to safety guarantees. At the same time, adaptivity in terms of migrating computation and communication to different devices in the fog-cloud continuum can be used to make the system more fault-tolerant by suitable design approaches. In this work we provide design approaches geared towards achieving safety and predictability of critical applications that run on adaptive fog computing platforms. To this end, we start by performing a survey of safety considerations in a fog computing system and identifying key safety challenges. We then propose a design approach to improve predictability in an autonomous mobile robot use-case in a factory setting designed using the fog computing paradigm. We narrow our attention on time-sensitive networking (TSN) and propose a temporal redundancy-based fault tolerance approach for time-sensitive messages. Furthermore, we study the 802.1CB TSN protocol and suggest improvements to reduce network congestion owing to replicated frames.As a future work, we intend to also include the wireless aspects in the evaluation of timeliness guarantees for safety-critical applications. The emphasis will be on run-time failure scenarios and self-healing mechanisms based on online decisions taken in concert with offline guarantees.
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| 5. |
- Desai, Nitin, 1986-, et al.
(författare)
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Enhancing Fault Detection in Time Sensitive Networks using Machine Learning
- 2020
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Ingår i: 2020 International Conference on COMmunication Systems and NETworkS, COMSNETS 2020. - : Institute of Electrical and Electronics Engineers Inc.. - 9781728131870 ; , s. 714-719
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Konferensbidrag (refereegranskat)abstract
- Time sensitive networking (TSN) is gaining attention in industrial automation networks since it brings essential real-time capabilities to the Ethernet layer. Safety-critical realtime applications based on TSN require both timeliness as well as fault-tolerance guarantees. The TSN standard 802.1CB introduces seamless redundancy mechanisms for time-sensitive data whereby each data frame is sequenced and duplicated across a redundant link to prevent single points of failure (most commonly, link failures). However, a major shortcoming of 802.1CB is the lack of fault detection mechanisms which can result in unnecessary replications even under good link conditions - clearly inefficient in terms of bandwidth use. This paper proposes a machine learning-based intelligent configuration synthesis mechanism that enhances bandwidth utilization by replicating frames only when a link has a higher propensity for failure.
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| 6. |
- Desai, Nitin, 1986-, et al.
(författare)
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MALOC : Building an adaptive scheduling and routing framework for rate-constrained TSN traffic
- 2022
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Ingår i: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA. - : Institute of Electrical and Electronics Engineers Inc.. - 9781665499965
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Konferensbidrag (refereegranskat)abstract
- Time Sensitive Networking (TSN) is a set of standards aimed at providing real-time guarantees over existing Ethernet standards. Worst-case traversal time (WCTT) analyses of network traffic are traditionally used in schedulability and routing analyses to determine feasible routes for traffic streams. However, worst-case conditions happen quite rarely from a probabilistic perspective. The typical or average-case traversal times are easier to compute and can be used as an effective design tool for routing and scheduling. In this paper, we present "MaLoC"or Maximally Loaded Common links for routing and scheduling of rate-constrained (RC) traffic in time-sensitive networks (TSN). The proposed framework employs a fully decentralized approach to route and schedule generation with only switch-local information. We further provide a preliminary evaluation of the proposed approach using a simple network topology.
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| 7. |
- Desai, Nitin, 1986-, et al.
(författare)
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Safety of fog-based industrial automation systems
- 2019
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Ingår i: IoT-Fog 2019 - Proceedings of the 2019 Workshop on Fog Computing and the IoT. - New York, NY, USA : Association for Computing Machinery, Inc. - 9781450366984 ; , s. 6-10
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Konferensbidrag (refereegranskat)abstract
- The Fog computing paradigm employing multiple technologies is expected to play a key role in a multitude of industrial applications by fulfilling futuristic requirements such as flexible and enhanced computing, storage, and networking capability closer to the field devices. While performance aspects of the Fog paradigm has been the central focus of researchers, safety aspects have not received enough attention so far. In this paper, we identify various safety challenges related to the Fog paradigm and provide specific safety design aspects as a step towards enhancing safety in industrial automation scenarios. We contextualize these ideas by invoking a distributed mobile robots use-case that can benefit from the use of the Fog paradigm.
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| 8. |
- Desai, Nitin, 1986-, et al.
(författare)
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Safety-oriented flexible design of Autonomous Mobile Robot systems
- 2019
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Ingår i: 2019 IEEE International Symposium on Systems Engineering ISSE 2019. - Edinburgh, United Kingdom. - 9781728117836
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Konferensbidrag (refereegranskat)abstract
- Current industrial automation applications particularly within the smart manufacturing domain require mobility, flexibility of deployment, and scalability. In addition to these, it is important to mitigate the risk of safety hazards. In this paper we discuss a flexible, granular, and software-based system design that aims to improve both security and safety of an autonomous mobile robot (AMR) based industrial automation systems. The decentralised control architecture ensures that safety-critical functions are distributed throughout the network. To this end, we first define system-level safety requirements and identify procedures required to satisfy safety-critical functions such as emergency-stop (E-Stop). We then explain the benefits provided by the proposed system architecture vis-a-vis its resilience towards potential safety hazards.
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| 9. |
- Dobrin, Radu, 1970-, et al.
(författare)
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On fault-tolerant scheduling of time sensitive networks
- 2019
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Ingår i: OpenAccess Series in Informatics. - : Schloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing. - 9783959771191
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Konferensbidrag (refereegranskat)abstract
- Time sensitive networking (TSN) is gaining attention in industrial automation networks since it brings essential real-time capabilities at the data link layer. Though it can provide deterministic latency under error free conditions, TSN still largely depends on space redundancy for improved reliability. In many scenarios, time redundancy could be an adequate as well as cost efficient alternative. Time redundancy in turn will have implications due to the need for over-provisions needed for timeliness guarantees. In this paper, we discuss how to embed fault-tolerance capability into TSN schedules and describe our approach using a simple example.
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| 10. |
- Feigin, Valery L., et al.
(författare)
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Global, regional, and national burden of stroke and its risk factors, 1990-2019 : a systematic analysis for the Global Burden of Disease Study 2019
- 2021
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Ingår i: Lancet Neurology. - : Elsevier. - 1474-4422 .- 1474-4465. ; 20:10, s. 795-820
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Tidskriftsartikel (refereegranskat)abstract
- Background Regularly updated data on stroke and its pathological types, including data on their incidence, prevalence, mortality, disability, risk factors, and epidemiological trends, are important for evidence-based stroke care planning and resource allocation. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) aims to provide a standardised and comprehensive measurement of these metrics at global, regional, and national levels. Methods We applied GBD 2019 analytical tools to calculate stroke incidence, prevalence, mortality, disability-adjusted life-years (DALYs), and the population attributable fraction (PAF) of DALYs (with corresponding 95% uncertainty intervals [UIs]) associated with 19 risk factors, for 204 countries and territories from 1990 to 2019. These estimates were provided for ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage, and all strokes combined, and stratified by sex, age group, and World Bank country income level. Findings In 2019, there were 12.2 million (95% UI 11.0-13.6) incident cases of stroke, 101 million (93.2-111) prevalent cases of stroke, 143 million (133-153) DALYs due to stroke, and 6.55 million (6.00-7.02) deaths from stroke. Globally, stroke remained the second-leading cause of death (11.6% [10.8-12.2] of total deaths) and the third-leading cause of death and disability combined (5.7% [5.1-6.2] of total DALYs) in 2019. From 1990 to 2019, the absolute number of incident strokes increased by 70.0% (67.0-73.0), prevalent strokes increased by 85.0% (83.0-88.0), deaths from stroke increased by 43.0% (31.0-55.0), and DALYs due to stroke increased by 32.0% (22.0-42.0). During the same period, age-standardised rates of stroke incidence decreased by 17.0% (15.0-18.0), mortality decreased by 36.0% (31.0-42.0), prevalence decreased by 6.0% (5.0-7.0), and DALYs decreased by 36.0% (31.0-42.0). However, among people younger than 70 years, prevalence rates increased by 22.0% (21.0-24.0) and incidence rates increased by 15.0% (12.0-18.0). In 2019, the age-standardised stroke-related mortality rate was 3.6 (3.5-3.8) times higher in the World Bank low-income group than in the World Bank high-income group, and the age-standardised stroke-related DALY rate was 3.7 (3.5-3.9) times higher in the low-income group than the high-income group. Ischaemic stroke constituted 62.4% of all incident strokes in 2019 (7.63 million [6.57-8.96]), while intracerebral haemorrhage constituted 27.9% (3.41 million [2.97-3.91]) and subarachnoid haemorrhage constituted 9.7% (1.18 million [1.01-1.39]). In 2019, the five leading risk factors for stroke were high systolic blood pressure (contributing to 79.6 million [67.7-90.8] DALYs or 55.5% [48.2-62.0] of total stroke DALYs), high body-mass index (34.9 million [22.3-48.6] DALYs or 24.3% [15.7-33.2]), high fasting plasma glucose (28.9 million [19.8-41.5] DALYs or 20.2% [13.8-29.1]), ambient particulate matter pollution (28.7 million [23.4-33.4] DALYs or 20.1% [16.6-23.0]), and smoking (25.3 million [22.6-28.2] DALYs or 17.6% [16.4-19.0]). Interpretation The annual number of strokes and deaths due to stroke increased substantially from 1990 to 2019, despite substantial reductions in age-standardised rates, particularly among people older than 70 years. The highest age-standardised stroke-related mortality and DALY rates were in the World Bank low-income group. The fastest-growing risk factor for stroke between 1990 and 2019 was high body-mass index. Without urgent implementation of effective primary prevention strategies, the stroke burden will probably continue to grow across the world, particularly in low-income countries.
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