| 1. |
- Bassi, Ezio, et al.
(författare)
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Powerline Communication in Electric Vehicles
- 2009
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Ingår i: IEEE International Electric Machines and Drives Conference (IEMDC'09). - 9781424442522 ; , s. 1749-1753
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Konferensbidrag (refereegranskat)abstract
- In full electric (EV) or hybrid electric (HEV) vehicles the onboard communication is a crucial issue, that can take advantage from a reliable and robust interaction among the embedded units (ECUs) providing among others the power and batteries management, services, accessories and supervision; an updated global view of the system under control (the car) can improve the quality of control, reliability, safety and comfort. Power Line Communication technology (PLC), that take advantage of the DC power line as a physical medium to exchange messages, according to standard protocols, is a candidate at substituting the actual wired solutions, by substantially reducing the cabling burden. The present paper aims at i) reviewing PLC technology for DC bus in the automotive sector; ii) defining the requirements of a reliable communication systems within a car environment, with special attention given to the data exchange needed by the more critical systems in EV and HEV, and namely the control of electrical actuators for traction; iii) describing a benchmark for testing the data transfer characteristics and performance, including details on proposed protocols and architectures and presenting experimental results on data channel characterization and transmission.
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| 2. |
- Behnam, Moris, et al.
(författare)
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A Hierarchical Approach for Reconfigurable and Adaptive Embedded Systems
- 2008
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Ingår i: APRES'08 Adaptive and Reconfigurable Embedded Systems. ; , s. 51-54
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Konferensbidrag (refereegranskat)abstract
- Adaptive and reconfigurable embedded systems have been gaining an increasing interest in the past year from both academics and industry. This paper presents our work on hierarchical scheduling frameworks (HSF) intended as a backbone architecture facilitating the implementation of operating system support for adaptability and reconfigurability.
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| 3. |
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| 4. |
- Behnam, Moris
(författare)
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Hierarchical Real Time Scheduling and Synchronization
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The Hierarchical Scheduling Framework (HSF) has been introduced to enable compositional schedulability analysis and execution of embedded software systems with real-time constraints. In this thesis, we consider a system consisting of a number of semi-independent components called subsystems, and these subsystems are allowed to share logical resources. The HSF provides CPU-time to the subsystems and it guarantees that the individual subsystems respect their allocated CPU budgets. However, if subsystems are allowed to share logical resources, extra complexity with respect to analysis and run-time mechanisms is introduced. In this thesis we address three issues related to hierarchical scheduling of semi-independent subsystems. In the first part, we investigate the feasibility of implementing the hierarchical scheduling framework in a commercial operating system, and we present the detailed figures of various key properties with respect to the overhead of the implementation. In the second part, we studied the problem of supporting shared resources in a hierarchical scheduling framework and we propose two different solutions to support resource sharing. The first proposed solution is called SIRAP, a synchronization protocol for resource sharing in hierarchically scheduled open real-time systems, and the second solution is an enhanced overrun mechanism. In the third part, we present a resource efficient approach to minimize system load (i.e., the collective CPU requirements to guarantee the schedulability of hierarchically scheduled subsystems). Our work is motivated from a tradeoff between reducing resource locking times and reducing system load. We formulate an optimization problem that determines the resource locking times of each individual subsystem with the goal of minimizing the system load subject to system schedulability. We present linear complexity algorithms to find an optimal solution to the problem, and we prove their correctness
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| 5. |
- Behnam, Moris, et al.
(författare)
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Improved SIRAP analysis for synchronization in hierarchical scheduled real-time systems
- 2009
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Ingår i: Proceedings of 14th IEEE International Conference on Emerging Techonologies and Factory (ETFA'09). - 9781424427284
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Konferensbidrag (refereegranskat)abstract
- We present our ongoing work on synchronization in hierarchical scheduled real-time systems, where tasks are scheduled using fixed-priority pre-emptive scheduling. In this paper, we show that the original local schedulability analysis of the synchronization protocol SIRAP is very pessimistic when tasks of a subsystem access many global shared resources. The analysis therefore suggests that a subsystem requires more CPU resources than necessary. A new way to perform the schedulability analysis is presented which can make the SIRAP protocol more efficient in terms of calculated CPU resource needs.
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| 6. |
- Behnam, Moris, et al.
(författare)
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Independent Abstraction and Dynamic Slack Reclaiming in Hierarchical Real-Time Open Systems
- 2007
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Ingår i: Proceedings of the Work-In-Progress (WIP) session of the 19th Euromicro Conference on Real-Time Systems (ECRTS'07), Pisa, Italy. ; , s. 1-4
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Konferensbidrag (refereegranskat)abstract
- Independent subsystem abstraction allows subsystems to be developed and validated separately and supports an easier subsystem integration. In particular, this approach is desirable in open systems, since it does not require knowledge of temporal behaviour of other subsystems. However, independentabstraction, assuming the worst-case CPU supply pattern, requires extra CPU allocations. We present our work in progress on dynamic slack reclamation, which keeps track of such extra CPU allocations at run time. We are also investigating how to utilize those extra resources for supporting soft real-time tasks.
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| 7. |
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| 8. |
- Behnam, Moris, et al.
(författare)
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Overrun Methods for Semi-Independent Real-Time Hierarchical Scheduling
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The Hierarchical Scheduling Framework (HSF) has been introduced as a design-time framework to enable compositional schedulability analysis of embedded software systems with real-time properties. In this paper a software system consists of a number of semi-independent components called subsystems. Subsystems are developed independently and later integrated to form a system. To support this design process, in the paper, the proposed methods allow non-intrusive configuration and tuning of subsystem timing-behaviour via subsystem interfaces for selecting scheduling parameters. This paper considers three methods to handle overruns due to resource sharing between subsystems in the HSF. For each one of these three overrun methods corresponding scheduling algorithms The work in this paper is supported by the Swedish Foundation for Strategic Research (SSF), via the research programme PROGRESS. and associated schedulability analysis are presented together with analysis that shows under what circumstances one or the other is preferred. The analysis is generalized to allow for both Fixed Priority Scheduling (FPS) and Earliest Deadline First (EDF) scheduling. Also, a further contribution of the paper is the technique of calculating resource-holding times within the framework under different scheduling algorithms. The resource holding times being an important parameter in the global schedulability analysis.
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| 9. |
- Behnam, Moris, et al.
(författare)
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Real-Time Subsystem Integration in the Presence of Shared Resources
- 2006
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Ingår i: Proceedings of the Work-In-Progress (WIP) session of the 27th IEEE Real-Time Systems Symposium (RTSS'06), Rio de Janeiro, Brazil.
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Konferensbidrag (refereegranskat)abstract
- We present our ongoing work to support the difficult, time consuming, and error-prone process of subsystem integration in the real-time domain. Our work will result in methods where independently developed subsystems, including both hard real-time and soft real-time functions, can be easily integrated without resulting unpredictable timing behaviour. The methods will also facilitate subsystem reuse, since a subsystem can easily be integrated in a new environment. Related research and methods are presented, together with our ongoing work in the area.
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| 10. |
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