Towards a Stochastic Occurrence-Based Modeling Approach for Stochastic CPSs

Cyber-Physical Systems (CPSs) face many challenges, one of which is the complexity of our world full of a variety of stochastic behavior. Due to the excess complexity the increasing number of need for autonomous long running components appears and gives rise to a special concern for energy so that a great challenge becomes open to us that how to model, analyze and make effective evaluation for either one or both of stochastic behavior and energy consumption. To solve the problem, we present a Stochastic Occurrence Hybrid Automata (SOHA) which unify all stochastic behavior into triggers among probabilistic events and use a unified way to describe both stochastic and deterministic events occurrence, besides introduce the energy function with time to model energy harvesting or consumption. In this paper, we give the formal syntax and semantics of SOHA based on labeled transition system and then propose a SOHA-based modeling approach that provides a more reasonable way to concisely model stochastic hybrid systems with the use of refinement and stochastic abstraction. This approach helps build a better model with hiding the details we may not concern, which is useful to the analysis in the future. To illustrate our approach and its benefit, we discuss a benchmark of hybrid systems Energy Aware Buildings as case study.