A Petri Net Approach to Fault Detection and Diagnosis in Distributed Systems Armen Aghasaryan, Renée Boubour, Eric Fabre, Claude Jard, Albert Benveniste

This report presents a new use of safe Petri nets in the eld of distributed Discrete Event Dynamic Systems, with application to telecommunication network management. This study has in its long range objectives to provide a generic supervisor, which can be easily distributed on a set of sensors. Petri nets are used to provide both a model and an algorithm in fault management domain. Key features of our approach are 1/ we take advantage of the ability of Petri Nets to model concurrency in distributed systems, 2/ we refuse using the marking graph in our algorithms in order to avoid state explosion and thus rely instead on the so-called partial order semantics of Petri Nets, and, 3/ our algorithms use net unfolding techniques associated with partial order semantics, and extend them to the probabilistic case by providing a generalized Viterbi algorithm. This report is composed of two independent parts. The rst one concentrates on application, motivations, and modelling. The second part is devoted to a precise mathematical modelling and to algorithms. In particular, an original notion of stochastic Petri net is developped, that provides fully independent behaviors to regions of the net that are not directly interacting. Une approche par r eseaux de Petri aux probl emes de d etection de panne et de diagnostic dans les syst emes distribu es R esum e : Ce rapport pr esente une utilisation originale des r eseaux de Petri dans le do-maine des syst emes a ev enements discrets distribu es. L'application vis ee concerne la gestion des pannes dans les r eseaux de t el ecommunications, et se donne comme objectif le d eve-loppement d'un syst eme de supervision distribu e sur un ensemble de capteurs du r eseau. L'approche d evelopp ee ici se distingue par plusieurs points: 1/ on utilise la capacit e na-turelle des r eseaux de Petri a mod eliser la concurrence dans les syst emes distribu es, 2/ on refuse de recourir au graphe de marquage dans les algorithmes de diagnostic, pour eviter l'explosion du nombre d' etats, 3/ on s'appuie au contraire sur la s emantique d'ordre partiel des r eseaux de Petri, notamment a travers les techniques de d epliage. Ce formalisme est muni d'un cadre probabiliste, dans lequel sont etendues les techniques classiques de diagnostic par programmation dynamique (algorithme de Viterbi). Le rapport est compos e de deux parties ind ependantes. La premi …