INESC-ID   Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento em Lisboa
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Inesc-ID Lisboa

“On-the-Fly Model Checking for Regular Alternation-Free Mu-Calculus” and “One Interface to Serve Them All”

05/17/2010 - 15:00
05/17/2010 - 16:30

"On-the-Fly Model Checking for Regular Alternation-Free Mu-Calculus”:

Model-checking is a successful technique for automatically verifying concurrent finite-state systems. When designing a model-checker, a good compromise must be made between the expressive power of the property description formalism, the complexity of the model-checking problem, and the user-friendliness of the interface. The logic we adopted is the regular alternation-free mu-calculus, an extension of the alternation-free mu-calculus with ACTL-like action formulas and PDL-like regular expressions, allowing a concise and intuitive description of safety, liveness, and (some) fairness properties over labelled transition systems (LTSs). The model-checking method consists in reformulating the verification problem as the local resolution of a boolean equation system (BES), which is carried out by linear-time algorithms based on various strategies (depth-first search, breadth-first search, etc.). These algorithms also generate full diagnostic information (examples and counterexamples) illustrating the truth value of temporal formulas. This method is at the heart of the EVALUATOR 3.5 model-checker of the CADP toolbox, developed using the generic OPEN/CAESAR environment for on-the-fly verification. The BES resolution algorithms are provided by the CAESAR_SOLVE library of OPEN/CAESAR.

“One Interface to Serve Them All” :

I will explain a new interface for model checking tools, which enables o connect many model checking algorithms (explicit, distributed, symbolic, multi-core) to various input languages (Promela, mCRL, DVE). Also, several generic optimizations can be applied at the interface. Additionally, I will demonstrate the application of model checking to safety requirements of railway interlocking systems, in a project led by the UIC (Union Internationale des Chemins de Fer).