Luigi Sassoli

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A modeling notation is introduced which extends time Petri nets with an additional mechanism of resource assignment making the progress of timed transitions be dependent on the availability of a set of preemptable resources. The resulting notation, which we call preemptive time Petri nets, permits natural description of complex real-time systems running(More)
Time Petri nets describe the state of a timed system through a marking and a set of clocks. If clocks take values in a dense domain, state space analysis must rely on equivalence classes. These support verification of logical sequencing and quantitative timing of events, but they are hard to be enriched with a stochastic characterization of nondeterminism(More)
Preemptive Time Petri Nets are obtained by extending Time Petri Nets with an additional mechanism of resource assignment which makes the progress of timed transitions be dependent on the availability of a set of preemptable resources, and with the capability to make transition times and priorities be dependent on the marking. The combination of these(More)
In the verification of reactive systems with nondeterministic densely valued temporal parameters, the state-space can be covered through equivalence classes, each composed of a discrete logical location and a dense variety of clock valuations encoded as a difference bounds matrix (DBM). The reachability relation among such classes enables qualitative(More)
Several techniques have been proposed for symbolic enumeration and analysis of the state space of reactive systems with non-deterministic temporal parameters taking values within a dense domain. In a large part of these techniques, the state space is covered by collecting states within equivalence classes each comprised of a discrete logical location and a(More)
Quantitative evaluation of models allowing multiple concurrent non-exponential timers requires enumeration and analysis of non-Markovian processes. In general, these processes may be not isomorphic to those obtained from the corresponding untimed models, due to implicit precedences induced by timing constraints on concurrent events. The analysis of(More)
We address the problem of test case selection and path sensitization in the process of testing real-time preemptive systems, following a formal methodology based on the theory of preemptive Time Petri Nets (pTPN) implemented in the Oris tool. We discuss practical factors that limit feasible behaviors in the implementation of a nondeterministic specification(More)
We describe a methodology for the construction of realtime tasking sets, which smoothly integrates a f o m l approach in both development and veriJication processes of the software life cycle. In the design stage, a timeline schema is used to specify concurrent processes with their dependencies and their expected temporal parameters. The schema is(More)