Author/Authors :
Benmessahel, B Computer Science Department - University of Ferhat Abbas Setif 1, Pole 2 - El Bez, Algeria , Touahria, M Computer Science Department - University of Ferhat Abbas Setif 1, Pole 2 - El Bez, Algeria , Nouioua, F University of Toulon, LSIS UMR 7296, Marseille, France , Gaber, J Computer Science Department - Universite de Technologie de Belfort Montbeliard, Rue Thierry Mieg, 90010 Belfort, France , Lorenz, P Computer Science Department - IUT, University of Haute Alsace, Colmar, France
Abstract :
This paper gives a decentralized approach to the problem of failure prognosis in the framework of fuzzy discrete event
systems (FDES). A notion of co-predictability is formalized for decentralized prognosis of FDESs, where several local
agents with fuzzy observability rather than crisp observability are used in the prognosis task. An FDES is said to
be co-predictable if each faulty event can be predicted prior to its occurrence by at least one local agent using the
observability of fuzzy events. The verification of the decentralized predictability is performed by constructing a fuzzy
co-verifier from a given FDES. The complexity of the fuzzy co-verifier is polynomial with respect to the FDES being
predicted, and is exponential with respect to the number of the local prognosis agents. Then, a necessary and sufficient
condition for the co-predictability of FDESs is given. In addition, we show that the proposed method may be used
to deal with the decentralized prognosis for both FDESs and crisp DESs. Finally, to illustrate the effectiveness of the
approach, some examples are provided.
Keywords :
Fuzzy systems , Fuzzy automata , Failure detection , Decentralized prognosis , Discrete-event systems , Co-predictability
