A Note on Fault Diagnosis Algorithms

In this paper we review algorithms for checking diagnosability of discrete-event systems and timed automata. We point out that the diagnosability problems in both cases reduce to the emptiness problem for (timed) B\"uchi automata. Moreover, it is known that, checking whether a discrete-event system is diagnosable, can also be reduced to checking bounded diagnosability. We establish a similar result for timed automata. We also provide a synthesis of the complexity results for the different fault diagnosis problems.Comment: Note: This paper is an extended version of the paper published in the proceedings of CDC'09, 48th IEEE Conference on Decision and Control and 28th Chinese Control Conference, Shanghai, P.R. China, December 2009

The Complexity of Codiagnosability for Discrete Event and Timed Systems

In this paper we study the fault codiagnosis problem for discrete event systems given by finite automata (FA) and timed systems given by timed automata (TA). We provide a uniform characterization of codiagnosability for FA and TA which extends the necessary and sufficient condition that characterizes diagnosability. We also settle the complexity of the codiagnosability problems both for FA and TA and show that codiagnosability is PSPACE-complete in both cases. For FA this improves on the previously known bound (EXPTIME) and for TA it is a new result. Finally we address the codiagnosis problem for TA under bounded resources and show it is 2EXPTIME-complete.Comment: 24 pages

Summary-Based Inter-Procedural Analysis via Modular Trace Refinement

We propose a generalisation of trace refinement for the verification of inter-procedural programs. Our method is a top-down modular, summary-based approach, and analyses inter-procedural programs by building function summaries on-demand and improving the summaries each time a function is analysed. Our method is sound, and complete relative to the existence of a modular Hoare proof for a non-recursive program. We have implemented a prototype analyser that demonstrates the main features of our approach and yields promising results

Timed automata for modelling caches and pipelines

In this paper, we focus on modelling the timing aspects of binary programs running on architectures featuring caches and pipelines. The objective is to obtain a timed automaton model to compute tight bounds for the worst-case execution time (WCET) of the programs using model-checking tehcniques.Author gratefully acknowledges the funding from projects TEC2011-28666-C04-02, TEC2014-58036-C4-3-R and grant BES-2012-055572, awarded by the Spanish Ministry of Economy and Competitivity

Structural translation from time petri nets to timed automata

International audienceIn this paper, we consider Time Petri Nets (TPN) where time is associated with transitions. We give a formal semantics for TPNs in terms of Timed Transition Systems. Then, we propose a translation from TPNs to Timed Automata (TA) that preserves the behavioral semantics (timed bisimilarity) of the TPNs. For the theory of TPNs this result is two-fold: i) reachability problems and more generally TCTL model-checking are decidable for bounded TPNs; ii) allowing strict time constraints on transitions for TPNs preserves the results described in i). The practical appli- cations of the translation are: i) one can specify a system using both TPNs and Timed Automata and a precise semantics is given to the composition; ii) one can use existing tools for analyzing timed automata (like Kronos, Uppaal or Cmc) to analyze TPNs. In this paper we describe the new feature of the tool Romeo that implements our translation of TPNs in the Uppaal input format. We also report on experiments carried out on various examples and compare the result of our method to state-of-the-art tool for analyzing TPNs

Structural Translation of Time Petri Nets into Timed Automata

International audienceIn this paper, we consider Time Petri Nets (TPN) where time is associated with transitions. We give a formal semantics for TPNs in terms of Timed Transition Systems. Then, we propose a translation from TPNs to Timed Automata (TA) that preserves the behavioural semantics (timed bisimilarity) of the TPNs. For the theory of TPNs this result is two-fold: i) reachability problems and more generally TCTL model-checking are decidable for bounded TPNs; ii) allowing strict time constraints on transitions for TPNs preserves the results described in i). The practical applications of the translation are: i) one can specify a system using both TPNs and Timed Automata and a precise semantics is given to the composition; ii) one can use existing tools for analysing timed automata (like KRONOS or UPPAAL or CMC) to analyse TPNs