| 1. |
- Mubeen, Saad, et al.
(author)
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Translating End-to-End Timing Requirements to Timing Analysis Model in Component-Based Distributed Real-Time Systems
- 2012
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In: ACM SIGBED Review. - : Association for Computing Machinery (ACM). - 1551-3688. ; 9:4
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Journal article (peer-reviewed)abstract
- Often, component-based real-time systems are modeled with trigger and data chains. The end-to-end timing requirements on trigger chains are different from those on data chains. For a trigger chain, the interest lies in the calculation of holistic response time and its comparison with end-to-end deadline. Whereas, the schedulability of a data chain requires a comparison between its end-to-end latencies and corresponding deadlines. We discuss the problem of translating end-to-end timing requirements unambiguously from component-based real-time systems into timing analysis models which are required as input by the analysis tools. We also provide preliminary guidelines for such translations in the existing industrial tool suite.
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| 2. |
- Afanasov, Mikhail, et al.
(author)
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Programming Support for Time-sensitive Adaptation in Cyberphysical Systems
- 2018
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In: ACM SIGBED Review. - : Association for Computing Machinery (ACM). - 1551-3688. ; 14:4, s. 27-32
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Journal article (peer-reviewed)abstract
- Cyberphysical systems (CPS) integrate embedded sensors,actuators, and computing elements for controlling physicalprocesses. Due to the intimate interactions with thesurrounding environment, CPS software must continuouslyadapt to changing conditions. Enacting adaptation decisionsis often subject to strict time requirements to ensure controlstability, while CPS software must operate within the tightresource constraints that characterize CPS platforms. Developersare typically left without dedicated programmingsupport to cope with these aspects. This results in either toneglect functional or timing issues that may potentially ariseor to invest significant efforts to implement hand-crafted solutions.We provide programming constructs that allow developersto simplify the specification of adaptive processingand to rely on well-defined time semantics. Our evaluationshows that using these constructs simplifies implementationswhile reducing developers’ effort, at the price of a modestmemory and processing overhead.
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| 3. |
- Afshar, Sara, et al.
(author)
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Integrating independently developed real-time applications on a shared multi-core architecture
- 2013
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In: ACM SIGBED Review, v. 10, n. 3. - : Association for Computing Machinery (ACM). ; , s. 49-56
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Conference paper (peer-reviewed)abstract
- The shift towards multi-core platforms has become inevitable from an industry perspective, therefore proper techniques are needed to deal with challenges related to this migration from single core architectures to a multi-core architecture. One of the main concerns for the system developers in this context is the migration of legacy real-time systems to multi-core architectures. To address this concern and to simplify migration, independently developed subsystems are abstracted with an interface, such that when working with multiple independently-developed subsystems to be integrated on a shared platform, one does not need to be aware of information or policies used in other subsystems in order to determine subsystem-level schedulability. Instead schedulability can be checked through their interfaces at the time of integration on a shared multi-core architecture. In this paper we propose a solution for the case where some of the independently-developed subsystems are distributed over more than one processor and we propose an approach to generate interfaces of subsystems that may share mutually exclusive resources.
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| 4. |
- Afshar, Sara, et al.
(author)
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Intra-component Resource Sharing on a Virtual Multiprocessor Platform
- 2016
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In: ACM SIGBED Review. - : Association for Computing Machinery (ACM). - 1551-3688. ; , s. 31-32
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Conference paper (peer-reviewed)abstract
- Component-based software development facilitates the development process of large and complex software systems. By the advent of multiprocessors, the independently developed components can be integrated on a multi-core platform to achieve an efficient use of system hardware and a decrease in system power consumption and costs. In this paper, we consider a virtual multiprocessor platform where each component can be dynamically allocated to any set of processors of the platform with a maximum concurrency level. Global-EDF is used for intra-component scheduling. The existing analysis for such systems have assumed that tasks are independent. In this paper, we enable intra-component resource sharing for this platform. We investigate using a spin-based resource sharing protocol with the accompanying analysis that extends the existing analysis for independent tasks. We briefly illustrate and evaluate our initial results with an example.
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| 5. |
- Afshar, Sara, et al.
(author)
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Resource Sharing among Prioritized Real-Time Applications on Multiprocessors
- 2015
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In: ACM SIGBED Review - Special Issue on the 6th International Workshop on Compositional Theory and Technology for Real-Time Embedded Systems. - : Association for Computing Machinery (ACM). ; , s. 46-55
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Conference paper (peer-reviewed)abstract
- In this paper, we propose a new protocol for handling resource sharing among prioritized real-time applications composed on a multiprocessor platform. We propose an optimal priority assignment algorithm which assigns unique priorities to the applications based on information in their interfaces. We have performed experimental evaluations to compare the proposed protocol (called MSOS-Priority) to the current state of the art locking protocols under multiprocessor partitioned scheduling, i.e., MPCP, MSRP, FMLP, MSOS, and OMLP. The valuations show that MSOS-Priority mostly performs significantly better than alternative approaches.
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| 6. |
- Ashjaei, Mohammad, et al.
(author)
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Dynamic Reconfiguration in Multi-Hop Switched Ethernet Networks
- 2014
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In: ACM SIGBED Review. Special Issue on 6th Workshop on Adaptive and Reconfigurable Embedded Systems (APRES 2014). - : Association for Computing Machinery (ACM). - 1551-3688. ; 11:3, s. 62-65
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Journal article (peer-reviewed)abstract
- The FTT-SE protocol provides adaptive real-time communication on Ethernet networks. To assure a continued real-time behavior, FTT-SE integrates admission control with a quality-of-service mechanism, which screen all adaptation and reconfiguration requests, accepting only those that do not compromise the system timeliness. The adaptability and reconfigurability have been deeply studied in the case of single switch FTT-SE architectures, whereas the extension of that for the multi-hop FTT-SE architecture was not yet investigated. Therefore, in this paper we study the challenges of enabling dynamic reconfiguration in multi-hop FTT-SE networks, we propose two methods (one centralized and one distributed) and we present a qualitative comparison between them.
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| 7. |
- Bagheri, M., et al.
(author)
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Runtime compositional analysis of track-based traffic control systems
- 2017
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In: ACM SIGBED Review. - : Association for Computing Machinery (ACM). - 1551-3688. ; 14:3, s. 38-39
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Journal article (peer-reviewed)abstract
- In this paper we address the development of dependable self-adaptive systems focusing on the specific domain of track-based traffic control systems where timing issues are critical.
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| 8. |
- Bakhshi Valojerdi, Zeinab, 1986-, et al.
(author)
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A preliminary roadmap for dependability research in fog computing
- 2020
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In: ACM SIGBED Review. - : Association for Computing Machinery. - 1551-3688. ; 16:4, s. 14-19
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Journal article (peer-reviewed)abstract
- Fog computing aims to support novel real-time applications by extending cloud resources to the network edge. This technology is highly heterogeneous and comprises a wide variety of devices interconnected through the so-called fog layer. Compared to traditional cloud infrastructure, fog presents more varied reliability challenges, due to its constrained resources and mobility of nodes. This paper summarizes current research efforts on fault tolerance and dependability in fog computing and identifies less investigated open problems, which constitute interesting research directions to make fogs more dependable.
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| 9. |
- Becker, Matthias, 1986-, et al.
(author)
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Analyzing end-to-end delays in automotive systems at various levels of timing information
- 2017
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In: ACM SIGBED Review. - : Association for Computing Machinery (ACM). - 1551-3688. ; 14:4, s. 8-13
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Journal article (peer-reviewed)abstract
- Software design for automotive systems is highly complex due to the presence of strict data age constraints for event chains in addition to task specific requirements. These age constraints define the maximum time for the propagation of data through an event chain consisting of independently triggered tasks. Tasks in event chains can have different periods, introducing over- and under-sampling effects, which additionally aggravates their timing analysis. Furthermore, different functionality in these systems, is developed by different suppliers before the final system integration on the ECU. The software itself is developed in a hardware agnostic manner and this uncertainty and limited information at the early design phases may not allow effective analysis of end-to-end delays during that phase. In this paper, we present a method to compute end-to-end delays given the information available in the design phases, thereby enabling timing analysis throughout the development process. The presented methods are evaluated with extensive experiments where the decreasing pessimism with increasing system information is shown.
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| 10. |
- Becker, Matthias, et al.
(author)
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Dynamic Power Management for Thermal Control of Many-Core Real-Time Systems
- 2014
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In: Sigbed Review. - : Association for Computing Machinery (ACM). - 1551-3688. ; 11:3, s. 26-29
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Journal article (peer-reviewed)abstract
- Many-Core systems, processors incorporating numerous cores interconnected by a Network on Chip (NoC), provide the computing power needed by future applications. High power density caused by the steadily shrinking transistor size, which is still following Moore's law, leads to a number of problems such as overheating cores, affecting processor reliability and lifetime. Embedded real-time systems are exposed to a changing ambient temperature and thus need to adapt their configuration in order to keep the individual core temperature below critical values. %Targeting embedded real-time systems, systems need to adapt to changing environments. In our approach a hysteresis controller is implemented on each core, triggering a redistribution of the cores and the transition into idle state allowing the core to cool down. We propose two approaches, one global and one local approach, to redistribute the tasks and relive overheating cores during runtime. We evaluate the two proposed approaches by comparing them against each other based on simulations.
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