4,749 research outputs found
Sampling and Timing: A Task for the Environmetal Process
Sampling and timing is considered a responsibility of the environment of controller software. In this paper we will illustrate a concept whereby an environmental process and multi-way events play an important role in applying timing for untimed CSP software architectures. We use this timing concept for building our control applications based on CSP concepts and with our CSP for C++ (CTC++) library. We present a concept of sampling of control applications that is orthogonal to the application. This implies global timing on the basis of timed events. We also support traditional local timing on the based of timed processes
Parametric Schedulability Analysis of Fixed Priority Real-Time Distributed Systems
Parametric analysis is a powerful tool for designing modern embedded systems,
because it permits to explore the space of design parameters, and to check the
robustness of the system with respect to variations of some uncontrollable
variable. In this paper, we address the problem of parametric schedulability
analysis of distributed real-time systems scheduled by fixed priority. In
particular, we propose two different approaches to parametric analysis: the
first one is a novel technique based on classical schedulability analysis,
whereas the second approach is based on model checking of Parametric Timed
Automata (PTA).
The proposed analytic method extends existing sensitivity analysis for single
processors to the case of a distributed system, supporting preemptive and
non-preemptive scheduling, jitters and unconstrained deadlines. Parametric
Timed Automata are used to model all possible behaviours of a distributed
system, and therefore it is a necessary and sufficient analysis. Both
techniques have been implemented in two software tools, and they have been
compared with classical holistic analysis on two meaningful test cases. The
results show that the analytic method provides results similar to classical
holistic analysis in a very efficient way, whereas the PTA approach is slower
but covers the entire space of solutions.Comment: Submitted to ECRTS 2013 (http://ecrts.eit.uni-kl.de/ecrts13
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Thunderstriking constraints with JUPITER
We present JUPITER, a tool for analysing multi-constrained systems. JUPITER was built to explore three basic ideas. First, how to use controller synthesis so as to find the exact conditions under which a particular constraint will be satisfied. Second, how to successively refine the models used for the controller synthesis so as to obtain a series of more easily understandable and more robust controllers. Last but not least, how to structure & explain the synthesised controllers and provide hints to designers for further optimisations through the use of machine learning techniques. Thus, JUPITER can help in the design and analysis of multi-constraint systems through the automatic synthesis of control logic for certain of the constraints and the aid it provides to designers for discovering further optimisations. The controllers it synthesises can be easily implemented on top of a standard real-time OS
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