| 1. |
- Hansson, Hans, et al.
(författare)
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Real-Time Systems
- 2010
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This is a textbook developed for use in the Master Programme Module E-M.6 "Real-Time Systems" as part of the Postgraduate Distance studies organized by Fraunhofer IESE and the Distance and International Studies Center at the Technical University of Kaiserslauten, Germany.
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| 2. |
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| 3. |
- Sentilles, Séverine, et al.
(författare)
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Save-IDE – A Tool for Design, Analysis andImplementation of Component-based Embedded Systems
- 2009
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Ingår i: 2009 31ST INTERNATIONAL CONFERENCE ON SOFTWARE ENGINEERING, PROCEEDINGS. - : IEEE Computer Society. - 9781424434534 ; , s. 607-610
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Konferensbidrag (refereegranskat)abstract
- The paper presents Save-IDE, an Integrated Development Environment for thedevelopment of component-based embedded systems. Save-IDE supports efficient development of dependable embedded systems by providing tools for design of embedded software systems using a dedicated component model, formal specification and analysis of component and system behaviors already in early development phases, and a fully automated transformation of the system of components into an executable image.
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| 4. |
- Yin, Hang, 1982-
(författare)
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Introducing Mode Switch in Component-Based Software Development
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Self-adaptivity, characterized by the ability to dynamically adjust behavior at runtime, is a growing trend in the evolution of modern embedded systems. While self-adaptive systems tend to be flexible and autonomous, self-adaptivity may inevitably complicate software design, test and analysis. A strategy for taming the growing software complexity of self-adaptive systems is to partition system behaviors into different operational modes specified at design time. Such a multi-mode system can change behavior by switching between modes at runtime under certain circumstances. Multi-mode systems can benefit from a complementary approach to the software development of complex systems: Component-Based Software Engineering (CBSE), which fosters reuse of independently developed software components. However, the state-of-the-art component-based development of multi-mode systems does not take full advantage of CBSE, as reuse of modes at component level is barely addressed. Modes are often treated as system properties, while mode switches are handled by a global mode manager. This centralized mode management entails global information of all components, whereas the global information may be inaccessible in component-based systems. Another potential problem is that a single mode manager does not scale well, particularly at design time, for a large number of components and modes. In this thesis we propose a distributed solution to the component-based development of multi-mode systems, aiming for a more efficient and scalable mode management. Our goal is to fully incorporate modes in software component reuse, supporting reuse of multi-mode components, i.e., components able to run in multiple modes. We have developed a generic framework, the Mode-Switch Logic (MSL), which not only supports reuse of multi-mode components but also provides runtime mechanisms for handling mode switch. MSL includes three fundamental elements: (1) a mode-aware component model with the formal specification of reusable multi-mode software components; (2) a mode mapping mechanism for the seamless composition of multi-mode components; and (3) a mode-switch runtime mechanism which is executed by each component in isolation from its functional execution and coordinates the mode switches of different components without the need of global mode information. The mode-switch runtime mechanism has been verified by model checking in conjunction with mathematical proofs. We also provide a mode-switch timing analysis for the runtime mechanism to respect real-time requirements. MSL is dedicated to the mode aspect of a system irrespective of component execution semantics, thus independent of the choice of component models. We have integrated MSL in the ProCom component model with the extension of support for reuse of multi-mode components and distributed mode-switch handling. Although the distributed mode-switch handling of MSL is more flexible and scalable than the conventional centralized approach, when components are deployed on a single hardware platform and global mode information is available, centralized mode-switch handling is more efficient in terms of runtime overhead and mode-switch time. Hence, MSL is supplemented with a mode transformation technique to enhance runtime mode-switch efficiency by converting the distributed mechanism to a centralized mechanism. MSL together with the mode transformation technique has been implemented in a prototype tool where one can build multi-mode systems by reusing multi-mode components. The applicability of MSL is demonstrated in two proof-of-concept case studies.
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| 5. |
- Åkerholm, Mikael, et al.
(författare)
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Handling Subsystems using the SaveComp Component Technology
- 2006
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Ingår i: Workshop on Models and Analysis for Automotive Systems (WMAAS'06) in conjunction with the 27th IEEE Real-Time Systems Symposium (RTSS'06), Rio de Janeiro, Brazil.
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Konferensbidrag (refereegranskat)
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| 6. |
- Åkerholm, Mikael, et al.
(författare)
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Handling Subsystems using the SaveComp Component Technology
- 2006
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Ingår i: Proceedings of Workshop on Models and Analysis for Automotive Systems (WMAAS'06).
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Konferensbidrag (refereegranskat)abstract
- This article presents a component technology (SaveCCT) suitable for the development of embedded vehicular control-system software. To satisfy the requirements in the vehicular domain, SaveCCT is designed to allow analysis and verification during the entire software development process.We give an overview of SaveCCT and its associated component model SaveCCM, together with an outline of how the framework intends to support the integration of larger -- possibly independently developed -- subsystems into a complete vehicle control system.
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| 7. |
- Åkerholm, Mikael, et al.
(författare)
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The SaveCCM Language Reference Manual
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This language reference describes the syntax and semantics of SaveCCM, acomponent modeling language for embedded systems designed with vehicle applications and safety concerns in focus. The SaveCCM component model wasdefined within the SAVE project. The SAVE components are influenced mainlyby the Rubus component technology, with a switch concept similar to thatin Koala. The semantics is defined by a transformation into timed automatawith tasks, a formalism that explicitly models timing and real-time task scheduling.The purpose of this document is to describe a semantics of the SAVE component modeling language, which can be used to describe timing and functional behavior of components. The model of a system is in some cases an over approximation of the actual system behavior. An implementation of a model can resolve non-determinism e.g. by merging tasks or assigning a scheduling policy (such as static scheduling or fixed priority, preemptive or not) that will resolvethe non-determinism.
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| 8. |
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| 9. |
- Åsberg, Mikael, et al.
(författare)
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Modelling, Verification and Synthesis of Two-Tier Hierarchical Fixed-Priority Preemptive Scheduling
- 2011
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Ingår i: Proceedings - 23rd EUROMICRO Conference on Real-Time Systems (ECRTS'11). - 9780769544427 ; , s. 172-181
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Konferensbidrag (refereegranskat)abstract
- Hierarchical scheduling has major benefits when it comes to integrating hard real-time applications. One of those benefits is that it gives a clear runtime separation of applications in the time domain. This in turn gives a protection against timing error propagation in between applications. However, these benefits rely on the assumption that the scheduler itself schedules applications correctly according to the scheduling parameters and the chosen scheduling policy. A faulty scheduler can affect all applications in a negative way. Hence, being able to guarantee that the scheduler is correct is of great importance. Therefore, in this paper, we study how properties of hierarchical scheduling can be verified. We model a hierarchically scheduled system using task automata, and we conduct verification with model checking using the Times tool. Further, we generate C-code from the model and we execute the hierarchical scheduler in the Vx Works kernel. The CPU and memory overhead of the modelled scheduler is compared against an equivalent manually coded two-level hierarchical scheduler. We show that the worst-case memory consumption is similar and that there is a considerable difference in CPU overhead.
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| 10. |
- Åsberg, Mikael, et al.
(författare)
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Prototyping and Code Synthesis of Hierarchically Scheduled Systems using TIMES
- 2010
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Ingår i: FTRA Journal of Convergence. - Seoul. - 2093-7741. ; 1:1, s. 75-84
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Tidskriftsartikel (refereegranskat)abstract
- In hierarchical scheduling a system is organized as a tree of nodes, where each node schedules its child nodes. A node contains tasks and/or subsystems, where a subsystem is typically developed by a development team. Given a system where each part is subcontracted to different developers, they can benefit from hierarchical scheduling by parallel development and simplified integration of subsystems. Each team should have the possibility to test their system before integration. Hence, we show how a node, in a hierarchical scheduling tree, can be analyzed in the Times tool by replacing all interference from nodes with a small set of higher priority tasks. We show an algorithm that can generate these tasks, including their parameters. Further, we use the Times code-generator, in combination with operating system extensions, to generate source code that emulates the scheduling environment for a subsystem, in an arbitrary level in the tree. Our experiments include two example systems. In the first case we generate source code for an industrial oriented platform (VxWorks) and conduct a performance evaluation. In the second example we generate source code that emulates the scheduling environment for a video application, running in Linux, and we perform a frame-rate evaluation.
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