1. Pisa, 11/25/2002Susanna Donatelli1 Modelling process and heterogeneous model construction Susanna Donatelli susi@di.unito.it Modelling and evaluation groups of the Dipartimento di Informatica Università del Piemonte Orientale, Alessandria (Italy) Dipartimento di Informatica Università di Torino Torino (Italy) http://www.di.unito.it/~qmips

2. Pisa, 11/25/2002Susanna Donatelli2 Who we are A group across two universities with: Balbo, Bobbio, Donatelli, Franceschinis, Anglano, Gaeta, Sereno, Ribaudo, Gribaudo, Horvath, Sproston; Basic research areas: performance evaluation, dependability analysis, probabilistic verification; Synergic national projects: Perf2002 on performance evaluation Wide national project on networked computing

3. Pisa, 11/25/2002Susanna Donatelli3 What do we work on Modelling process (model structure from requirements, automatic production of submodels) Formalisms (Stochastic Petri nets, Fluid Petri nets, combinatorial models, stochastic process algebras, automata based formalisms) Solutions (Kronecker based, discrete PH approximations, distribution fitting, symmetries exploitation) Applications (automation systems, software solutions to FT, telecom-wireless, web servers, call centers, task scheduling)

4. Pisa, 11/25/2002Susanna Donatelli4 Model construction through the life cycle Building the model from the early development phases (and also “design for evaluation”) Which model for which index (an issue especially in dependability) Abstraction/inheritance

5. Pisa, 11/25/2002Susanna Donatelli5 Model construction from the early phases UML-CD Customized UML-CD Predefined TRIO Customized TRIO Parametric GSPN Customized GSPN UML Behavioural diagrams Modeller experience Rules and predefined models Automatic translation Customization guidelines Customization and refinement Info from customization

6. Pisa, 11/25/2002Susanna Donatelli6 Chain of models –Fault tree (combinatorial) –Dynamic FT and Bayesian (localized dependencies) –Markov models / Petri nets (state based)

7. Pisa, 11/25/2002Susanna Donatelli7 State Space based? –Continuous vs discrete state space –Continuous vs discrete time –Stochastic Infinite support Finite support Deterministic –Timed Deterministic Non-deterministic upon an interval Non-deterministic upon choices

8. Pisa, 11/25/2002Susanna Donatelli8 Which evaluation? Evaluation: classical dependability measures either steady state or transient Validation: state or path formulas being true or false Probabilistic verification

9. Pisa, 11/25/2002Susanna Donatelli9 Putting all together………. Unifying concepts for integrating tools From requirements to indices

10. Pisa, 11/25/2002Susanna Donatelli10 Means………………….. Work also with people in formal design and validation Comparing formalisms Look for synergies in the solution field (e.g. Matrix diagram and symbolic reachability graph) Tools