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...terms of state-set size and computation time. 4.1 Test Specification For our experiment we used a slightly changed and adopted specification of a simple railway control system originally published in =-=[37]-=- and found in UPPAAL distribution. A rail-road intersection controller monitors trains on a set of rail-road tracks with a shared track segment, e.g. a train-station. Its main objective is to ensure t...

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...to denote the initial symbolic global time state for networks, where D 0 = ({u 0 }) ↑ ∧ I(l 0 ). We write (l, D) ⇒ (l ′ , D ′ ) if (l ′ , D ′ ) = spt(α)(l, D) for some action α. It can be shown (e.g. =-=[YPD94]-=-) that the symbolic semantics characterizes the concrete semantics given earlier in the following sense: Theorem 1. A state (l, u) of a network is reachable if and only if (l 0 , D 0 )(⇒ ) ∗ (l, D) fo...

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...a scheduling problem. We can add topological and timing constraints easily without being forced to change the underlying algorithms. The model checking algorithm as it is implemented in UPPAAL so far =-=[13]-=- does not allow to determine the minimal makespan straightforward, but forces us to determine for several deadlines if a feasible schedule exists. We will investigate whether it is possible to incorpo...

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...ueue, we may only be interested in the reachability of locations. A nice property of our extension is that the location reachability problem can be checked by the same technique as for timed automata =-=[14, 19]-=-. So we may view the original timed automaton (without task assignment) as an abstraction of its extended version preserving location reachability. The existing model checking tools such as [20, 17] c...

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...g and onthe -fly techniques. It consists of three main parts: a description language, a simulator and a model-checker. It is appropriate for systems that can be modelled as networks of timed automata =-=[3, 2]-=-, i.e. a collection of non-deterministic processes with finite control structure and real-valued clocks, communicating through channels and shared variables. The description language of Uppaal is a no...

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...asses, and to compute the timed test sequences, we employ efficient symbolic reachability techniques based on constraint solving that have recently been developed for model checking of timed automata =-=[15, 6, 28, 4, 18]-=-. In summary, the contributions of the paper are: – We propose a coarse equivalence class partitioning of the state space and use this for automatic test selection. – Other work on test generation for...

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...nt construct. However, if one restricts to only using the invariant construct (as introduced in Section 6), the more standard model of timed automata is retained with all its compositional properties =-=[23,50,59]-=-. The latter model is tailored towards hard-real time systems. (In this model patience and impatience coincide). Timed automata with deadlines 8 , on the other hand, have originally been introduced fo...