5,223 research outputs found
Timed Automata Semantics for Analyzing Creol
We give a real-time semantics for the concurrent, object-oriented modeling
language Creol, by mapping Creol processes to a network of timed automata. We
can use our semantics to verify real time properties of Creol objects, in
particular to see whether processes can be scheduled correctly and meet their
end-to-end deadlines. Real-time Creol can be useful for analyzing, for
instance, abstract models of multi-core embedded systems. We show how analysis
can be done in Uppaal.Comment: In Proceedings FOCLASA 2010, arXiv:1007.499
Symbolic Algorithms for Language Equivalence and Kleene Algebra with Tests
We first propose algorithms for checking language equivalence of finite
automata over a large alphabet. We use symbolic automata, where the transition
function is compactly represented using a (multi-terminal) binary decision
diagrams (BDD). The key idea consists in computing a bisimulation by exploring
reachable pairs symbolically, so as to avoid redundancies. This idea can be
combined with already existing optimisations, and we show in particular a nice
integration with the disjoint sets forest data-structure from Hopcroft and
Karp's standard algorithm. Then we consider Kleene algebra with tests (KAT), an
algebraic theory that can be used for verification in various domains ranging
from compiler optimisation to network programming analysis. This theory is
decidable by reduction to language equivalence of automata on guarded strings,
a particular kind of automata that have exponentially large alphabets. We
propose several methods allowing to construct symbolic automata out of KAT
expressions, based either on Brzozowski's derivatives or standard automata
constructions. All in all, this results in efficient algorithms for deciding
equivalence of KAT expressions
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