Network codiagnosability of Discrete-Event Systems subject to event communication delays

Codiagnosability of Networked Discrete Event Systems With Timing Structure

“…The problem of DES subject to unreliable observations of events was addressed in [54] and [61] (in the context of failure diagnosis) without considering communication networks. In this work, we model the loss of observation based on the technique proposed by CARVALHO et al in [54] In [42,43], the definition of network codiagnosability of DES subject to event communication delays was introduced, where the concept of step [33,35] was used to measure communication delays, i.e., k ∈ N steps accounts for the occurrence of, at most, k events until the information of the event executed by the plant arrives at the local diagnoser. In this thesis, we propose a new approach called networked discrete event systems with timing structure (NDESWTS) by adding two parameters to the automaton that models the system behavior as follows: (i) the maximal time communication delays between the distributed measurement sites in the plant and the local diagnosers; (ii) a minimal time function that is associated with each plant automaton transition, which corresponds to the minimal time the system must remain in the state before the transition can fire.…”

“…In this thesis, we propose a new approach called networked discrete event systems with timing structure (NDESWTS) by adding two parameters to the automaton that models the system behavior as follows: (i) the maximal time communication delays between the distributed measurement sites in the plant and the local diagnosers; (ii) a minimal time function that is associated with each plant automaton transition, which corresponds to the minimal time the system must remain in the state before the transition can fire. Regarding the modeling of the observation of the events by a local diagnoser subject to delay and losses, NUNES et al [42,43] carried out it in two steps as follows: in first step, an automaton that model the effects of the delays is proposed; in the second step, the automaton that models the observation of the events by a local diagnoser is computed by performing the parallel composition between the automaton obtained in the previous step and the automaton that models the plant. In this thesis, we propose an algorithm to consider the models the observation of the events by a local diagnoser subject to delay and losses without this intermediate step.…”

“…We introduce a new timed model that represents the dynamic system behavior of the plant based on the, a priori, knowledge of the minimal firing time for each transition of the plant and on the maximal delays in the event observation after it is recorded in the MS. In order to avoid using the concept of step [33,42,43] or the TDES [69],…”

“…In order to deal with these problems, some relevant theoretical approaches have been considered in the literature, regarding supervisory control [27][28][29][30][31][32][33][34][35][36][37][38][39] and failure diagnosis [40][41][42][43] of networked discrete event systems.…”

“…We address, in this thesis, the problem of failure diagnosis of DES subject to delays and losses in the transmission of observed events from measurement sites (MS) to local diagnosers (LD). Such a failure diagnosis problem is referred, in the literature to as codiagnosability of networked discrete event systems [42,43]. In addition, we revisit the codiagnosability of discrete event system problem in order to provide some contributions as follows.…”