Resilience of Timed Systems

S Akshay (1) , Blaise Genest (2) , Loïc Hélouët (2) , S Krishna (1) , Sparsa Roychowdhury (1)

1 IIT Bombay - Indian Institute of Technology Bombay
2 SUMO - SUpervision of large MOdular and distributed systems

This paper addresses reliability of timed systems in the setting of resilience, that considers the behaviors of a system when unspecified timing errors such as missed deadlines occur. Given a fault model that allows transitions to fire later than allowed by their guard, a system is universally resilient (or self-resilient) if after a fault, it always returns to a timed behavior of the non-faulty system. It is existentially resilient if after a fault, there exists a way to return to a timed behavior of the non-faulty system, that is, if there exists a controller which can guide the system back to a normal behavior. We show that universal resilience of timed automata is undecidable, while existential resilience is decidable, in EXPSPACE. To obtain better complexity bounds and decidability of universal resilience, we consider untimed resilience, as well as subclasses of timed automata.

Mots clés: Timed automata; Fault tolerance; Integer-resets; Resilience

Domaines: Théorie et langage formel [cs.FL]

S Akshay, Blaise Genest, Loïc Hélouët, S Krishna, Sparsa Roychowdhury. Resilience of Timed Systems. FSTTCS 2021 - 41st IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science, IARCS, Dec 2021, Virtual Conference due to COVID, India. pp.1-22, ⟨10.4230/LIPIcs.FSTTCS.2021.33⟩. ⟨hal-03439247⟩