Time-Bounded Model Checking of Infinite-State Continuous-Time Markov Chains

The design of complex concurrent systems often involves intricate performance and dependability considerations. Continuous-time Markov chains (CTMCs) are widely used models for concurrent system designs making it possible to model check such properties. In this paper we focus on probabilistic timing properties of infinite-state CTMCs, expressible in continuous stochastic logic (CSL). Such properties comprise important dependability measures, such as timed probabilistic reachability, performability, survivability, and various availability measures like instantaneous availabilities, conditional instantaneous availabilities and interval availabilities. Conventional model checkers explore the given model exhaustively which is not always possible either due to state explosion or because the model is infinite. This paper presents a method that only explores the infinite (or prohibitively large) model up to a finite depth, with the depth bound being computed on-the-fly. We provide experimental evidence showing that our method is effective.