Strengthening architectures of smart CPS by modeling them as runtime product-lines

Smart Cyber-Physical Systems (CPS) are complex distributed decentralized systems of cooperating mobile and stationary devices which closely interact with the physical environment. Although Component-Based Development (CBD) might seem as a viable solution to target the complexity of smart CPS, existing component models scarcely cope with the open-ended and very dynamic nature of smart CPS. This is especially true for design-time modeling using hierarchical explicit architectures, which traditionally provide an excellent means of coping with complexity by providing multiple levels of abstractions and explicitly specifying communication links between component instances. In this paper we propose a modeling method (materialized in the SOFA NG component model) which conveys the benefits of explicit architectures of hierarchical components to the design of smart CPS. Specifically, we base our method on modeling systems as reference architectures of Software Product Lines (SPL). Contrary to traditional SPL, which is a fully design-time approach, we create SPL configurations at runtime. We do so in a decentralized way by translating the configuration process to the process of establishing component ensembles (i.e. dynamic cooperation groups of components) of our DEECo component model.