Optimal Time-Bounded Reachability Analysis for Concurrent Systems

Yuliya Butkova, Gereon Fox

Abstract: Efficient optimal scheduling for concurrent systems on a finite horizon is a challenging task up to date: Not only does time have a continuous domain, but in addition there are exponentially many possible decisions to choose from at every time point. In this paper we present a solution to the problem of optimal time-bounded reachability for Markov automata, one of the most general formalisms for modelling concurrent systems. Our algorithm is based on the discretisation of the time horizon. In contrast to most existing algorithms for similar problems, the discretisation step is not fixed. We attempt to discretise only in those time points when the optimal scheduler in fact changes its decision. Our empirical evaluation demonstrates that the algorithm improves on existing solutions up to several orders of magnitude.