|Authors: (Gianfranco Lamperti, Marina Zanella, Dipartimento di Ingegneria dell’Informazione, Universita degli Studi di Brescia, Italy)
Active systems are a class of discrete-event systems (DESs) that has been the focus of the
authors’ research over the last decade [?, ?, ?, ?, ?, ?, ?]. Based on past work, by now
the awareness has grown that, in order to cope with model-based diagnosis of DESs, it is
not enough to model them as composite systems, as done by most approaches [?, ?, ?, ?],
it is also necessary to process them in a stepwise, modular way. This is the reason for
the proposal of a problem – decomposition, solution – composition paradigm for modelbased
diagnosis of active systems [?], and for an increasing use of decentralized features,
such as the observation [?], or the diagnosis method [?] of other classes of DESs. All
these contributions denote progressive attempts to pinpoint some major requirements of
distributed model-based diagnosis (DMBD) of DESs.
This chapter defines and substantiates the task of (general) DMBD of active systems
with the support of six requirements. Specifically, Sections 2 through 7 introduce the requirements
guiding the formulation of DMBD, and instantiate them in the domain of active
systems. In particular, Section 6 emphasizes the issue of processing optimization by introducing
Active Algebra and relevant equivalence rules, while Section 7 deals with a method
for monotonically updating a complete set of candidate diagnosis during the processing.
Related work is discussed in Section 8. Conclusions are drawn in Section 9.