July 2, 2007 Research at the SW Technologies Lab (Time Petri Nets - - PowerPoint PPT Presentation

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WIRTES 07 WIRTES - Pisa, July07 Primo Workshop Italiano su Real-Time Embedded Systems July 2, 2007 Research at the SW Technologies Lab (Time Petri Nets nella verifica e valutazione di sistemi real-time) Giacomo Bucci, Laura Carnevali, Luigi

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WIRTES 07 Primo Workshop Italiano su Real-Time Embedded Systems

Research at the SW Technologies Lab

(Time Petri Nets nella verifica e valutazione di sistemi real-time) Giacomo Bucci, Laura Carnevali, Luigi Sassoli, Enrico Vicario

Sw Technologies Lab, Dept.Sistemi e Informatica, University of Florence vicario@dsi.unifi.it, www.dsi.unifi.it/~vicario

July 2, 2007

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SW Technologies Lab

People

G.Bucci, E.Vicario, A.Fantechi L.Sassoli,F.Baldini,L.Carnevali,L.Grassi,V.Sandrucci,F.Poli,A.Rugnone,J.Torrini, M.Banci, G.Lombardi, E.Spinicci, G.Falcini

Collaborations

Galileo Avionica, Regione Toscana, GE Transportation Systems, Marelli I+, Rigel, Planet, Rinascimento Digitale, ITTIG.CNR, ISTI.CNR Polo biotecnologico di unifi, Azienda Ospedaliera Careggi, …

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3 main areas of experitze

SW architectures and development practices (Bucci,Vicario)

Enterprise architectures and application interoperability (eGovernment ) Ontological architectures and applications Workflow management architectures OO Testing Focus on experimentation, development capability, technology transfer

Qualitative verification and quantitative evaluation (Bucci,Vicario)

Nondeterministic/stochastic, timed, reactive systems

Time Petri Nets, preemptiveTPN, stochasticTPN, …
Symbolic state space analysis

Real time testing

Formal modelling of embedded safety critical systems (Fantechi)

Specific focus on railway signaling systems Model driven development

modeling, model checking, automatic code generation,

code deployment on target, system testing Experimentation with commercial modelling tools

IAR Visualstate, Ilogix Statemate, Matlab Stateflow, Esterel Tech.SCADE

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Verification of reactive, timed, non deterministic systems

Sequencing of events Min-max time between events

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Reactive, dense timed, non-deterministic, non-preemptive systems
Symbolic state space analysis

State classes, Difference Bound Matrix, symbolic runs

IEEE TSE01: vicario

Time Petri Nets (TPN)

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Represents suspension

breaks DBM encoding

Tight DBM approximation,
Selection of critical paths and clean-up of false behaviors
IEEE TSE04: bucci, fedeli, sassoli, vicario

Preemptive Time Petri Nets (pTPN)

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Communicating Time Petri Nets (cmTPN)

Modular decomposition

TPN without preemption

Separate state space enumeration, required/provided interface
Projection and composition
IEEE TSE95: bucci, vicario

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Real Time testing

Exploit theory of pTPN to support design and testing
Integration in process standards

RTCA 178B, V-model, … architecture design and validation, disciplined coding, execution time profiling test case selection, sensitization, oracle, coverage analysis Collaboration with Galileo Avionica

Experimentation on Linux-RTAI
ECRTS07, ETFA07: carnevali, sassoli, vicario

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Quantitative evaluation of stochastic reactive timed systems

Associate non-determinism with a stochastic characterization

Instantaneous choices
Temporal parameters

Provide a measure of probability for alternative behaviors

Symbolic runs
Run timings

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Time intervals associated with general distribution
Discrete time

Maximal step semantics, confusion and well definedness

Stochastic state transition system

Embeds a Discrete Time Markov Chain Joint verification of possible behaviors and evaluation of their probability E.g. overrun handling policies: correctness and efficiency

IEEE TSE05: bucci, sassoli, vicario

stochastic preemptive Time Petri Nets

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stochastic Time Petri Nets

Dense time, no preemption
Extend state classes with state density

symbolic calculus of density functions Mathematica API, c++ implementation for exp-polynomial distributions

Stochastic extension of the class graph

regeneration classes and boundedness Markov renewal theory, Continuous Time Markov Chain

QEST05, QEST06, QEST07: bucci, sassoli, vicario

Main work under revision at IEEE TSE: sassoli, vicario

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Tool support

All results implemented in the ORIS tool

Plug-in architecture C++/Java http://www.stlab.dsi.unifi.it/oris/index.html

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