Model checking temporal knowledge and commitments in multi-agent systems using reduction
Though modeling and verifying Multi-Agent Systems (MASs) have long been under study,
there are still challenges when many different aspects need to be considered simultaneously.
In fact, various frameworks have been carried out for modeling and verifying
MASs with respect to knowledge and social commitments independently. However, considering
them under the same framework still needs further investigation, particularly
from the verification perspective. In this article, we present a new technique for model
checking the logic of knowledge and commitments (CTLKC+). The proposed technique is
fully-automatic and reduction-based in which we transform the problem of model checking
CTLKC+ into the problem of model checking an existing logic of action called ARCTL.
Concretely, we construct a set of transformation rules to formally reduce the CTLKC+ model
into an ARCTL model and CTLKC+ formulae into ARCTL formulae to get benefit from the
extended version of NuSMV symbolic model checker of ARCTL. Compared to a recent
approach that reduces the problem of model checking CTLKC+ to another logic of action
called GCTL?, our technique has better scalability and efficiency. We also analyze the complexity
of the proposed model checking technique. The results of this analysis reveal that
the complexity of our reduction-based procedure is PSPACE-complete for local concurrent
programs with respect to the size of these programs and the length of the formula being
checked. From the time perspective, we prove that the complexity of the proposed
approach is P-complete with regard to the size of the model and length of the formula,
which makes it efficient. Finally, we implement our model checking approach on top of
extended NuSMV and report verification results for the verification of the NetBill protocol,
taken from business domain, against some desirable properties. The obtained results show
the effectiveness of our model checking approach when the system scales up.