Computer Science

In this paper, we propose an abstract interpretation-based framework for reducing the state space of stochastic semantics for protein-protein interaction networks. Our approach consists in quotienting the state space of networks. Yet interestingly, we do not apply the widely-used strong lumpability criterion which imposes that two equivalent states behave similarly with respect to the quotient, but a weak version of it. More precisely, our framework detects and proves some invariants about the dynamics of the system: indeed the quotient of the state space is such that the probability of being in a given state knowing that this state is in a given equivalence class, is an invariant of the semantics. Then we introduce an individual-based stochastic semantics (where each agent is identified by a unique identifier) for the programs of a rule-based language (namely Kappa) and we use our abstraction framework for deriving a sound population-based semantics and a sound fragments-based sema...

In this paper, we show how thread partitioning helps in proving properties of mobile systems. Thread partitioning consists in gathering the threads of a mobile system into several classes. The partitioning criterion is left as a parameter of both the mobility model and the properties we are interested in. Then, we design a polynomial time abstract interpretation-based static analysis that counts the number of threads inside each partition class.

Sicherheitskritische eingebettete Systeme mussen hohen Qualitatsanforderungen genugen. Laufzeitfehler, z.B. arithmetische Uberlaufe oder Rundungsfehler konnen zu fehlerhaftem Programmverhalten fuhren. Da in der Regel keine vollstandige Testabdeckung moglich ist, bieten sich statische Analysatoren an. Diese bieten eine vollstandige Coverage, konnen jedoch Fehlalarme erzeugen. Da jeder potentielle Laufzeitfehler manuell vom Benutzer uberpruft werden muss, kann eine hohe Zahl von Fehlalarmen dazu fuhren, dass echte Fehler ubersehen werden. Der statische Analysator Astree kann durch Spezialisierung und Parametrisierung an die zu analysierende Software angepasst werden. Dies ermoglicht kurze Analysezeiten und eine niedrige Zahl von Fehlalarmen. Astree wird z.B. bei der Zertifizierung von industrieller Flugzeugsteuerungssoftware eingesetzt. Safety-critical embedded software has to satisfy stringent quality.

This paper reports the results of an ESA funded project on the use of abstract interpretation to validate critical real-time embedded space software. Abstract interpretation is industrially used since several years, especially for the validation of the Ariane 5 launcher. However, the limitations of the tools used so far prevented a wider deployment. Astrium Space Transportation, CEA, and ENS have analyzed the performances of two recent tools on a case study extracted from the safety software of the ATV: * ASTREE, developed by ENS and CNRS, to check for run-time errors, * FLUCTUAT, developed by CEA, to analyse the accuracy of numerical computations. The conclusion of the study is that the performance of this new generation of tools has dramatically increased (no false alarms and fine analysis of numerical precision).

Formal methods are increasingly used to help ensuring the correctness of complex, critical embedded software systems. We show how sound semantic static analyses based on Interpretation may be used to check properties at various levels of a software design: from high level models to low level binary code. After a short introduction to the Abstract Interpretation theory, we present a few current applications: checking for run-time errors at the C level, translation validation from C to assembly, and analyzing SAO models of communicating synchronous systems with imperfect clocks. We conclude by briey proposing some requirements to apply Abstract Interpretation to modeling languages such as UML.

In this paper, we show how thread partitioning helps in proving prop- erties of mobile systems. Thread partitioning consists in gathering the threads of a mobile system into several classes. The partitioning criterion is left as a parameter of both the mobility model and the properties we are interested in. Then, we design a polynomial time abstract interpretation- based static analysis that counts the number of threads inside each parti- tion class.