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— This paper studies the semantics of hierarchical finite state machines (FMS's) that are composed using various concurrency models, particularly dataflow, discrete-events, and synchronous/reactive modeling. It is argued that all three combinations are useful, and that the concurrency model can be selected independently of the decision to use hierarchical(More)
Our goal is to automatically obtain a distributed and fault-tolerant embedded system: distributed because the system must run on a distributed architecture; fault-tolerant because the system is critical. Our starting point is a source algorithm, a target distributed architecture, some distribution constraints, some indications on the execution times of the(More)
The paper introduces a higher-order synchronous data-flow language in which communication channels may themselves transport programs. This provides a mean to dynamically reconfigure data-flow processes. The language comes as a natural and strict extension of both <sc>lustre</sc> and <sc>lucy</sc>. This extension is conservative, in the sense that a(More)
—This paper addresses the problem of automatically distributing reactive systems. We first show that the use of synchronous languages allows a natural parallel description of such systems, regardless of any distribution problems. Then, a desired distribution can be easily specified, and achieved with the algorithm presented here. This distribution technique(More)
We address the problem of off-line fault tolerant scheduling of an algorithm onto a multiprocessor architecture with distributed memory and provide a generic algorithm which solves this problem. We take into account two kinds of failures: fail-silent and omission. The basic technique we use is the replication of operations and data communications. We then(More)
For autonomous critical real-time embedded (e.g., satellite), guaranteeing a very high level of reliability is as important as keeping the power consumption as low as possible. We propose an off-line scheduling heuristic which, from a given software application graph and a given multiprocessor architecture (homogeneous and fully connected), produces a(More)
The precision of an analysis based on abstract interpretation does not only depend on the abstract domain, but also on the solving method. The traditional solution is to solve iteratively abstract fixpoint equations, using extrapolation with a widening operator to make the iterations converge. Unfortunately, this extrapolation often loses crucial(More)
We propose a safe design method for safe execution systems, based on fault-tolerance techniques: it uses optimal discrete controller synthesis (DCS) to generate a correct-by-construction fault-tolerant system. The properties enforced concern consistent execution, functionality fulfillment (whatever the faults, under some failure hypothesis), and several(More)