A Compositional Modelling and Verification Framework for Stochastic Hybrid Systems

Abstract

Abstract In this paper, we propose a general compositional approach for modelling and verification of stochastic hybrid systems (SHSs). We extend Hybrid CSP (HCSP), a very expressive process algebra-like formal modeling language for hybrid systems, by introducing probability and stochasticity to model SHSs, which we call stochastic HCSP (SHCSP). Especially, non-deterministic choice is replaced by probabilistic choice, ordinary differential equations are replaced by stochastic differential equations (SDEs), and communication interrupts are generalized by communication interrupts with weights. We extend Hybrid Hoare Logic to specify and reason about SHCSP processes: On the one hand, we introduce the probabilistic formulas for describing probabilistic states, and on the other hand, we propose the notions of local stochastic differential invariants for characterizing SDEs and global loop invariants for repetition. Throughout the paper, we demonstrate our approach by an aircraft running example.