Interoperability of non-functional requirements in complex systems

Heterogeneity of embedded systems leads to the development of variable software, such as software product lines. From such a family of programs, stakeholders select the specific variant that satisfies their functional requirements. However, different functionality exposes different non-functional properties of these variants. Especially in the embedded-system domain, non-functional requirements are vital, because resources are scarce. Hence, when selecting an appropriate variant, we have to fulfill also non-functional requirements. Since more systems are interconnected, the challenge is to find a variant that additionally satisfies global nonfunctional (or quality) requirements. In this paper, we advert the problem of achieving interoperability of non-functional requirements among multiple interacting systems using a real-world scenario. Furthermore, we show an approach to find optimal variants for multiple systems that reduces computation effort by means of a stepwise configuration process.