Incremental, Distributed, and Concurrent Service Coordination for Reliable and Deterministic Systems-of-Systems

Systems-of-systems (SoS) are gaining increasing attention for the realization of safety-relevant applications with reliability and real-time requirements, by coordinating autonomous constituent systems from different application areas. For a given application that is initiated at a constituent system, the provision and use of services between constituent systems must be coordinated. This involves identifying constituent systems that can provide the services, optimizing the use of the services driven by extra-functional properties, performing admission control for service provision, reserving resources for provided services, and recursively using services from subcontracted constituent systems to realize service provisions. In this article, new conceptual models with service provisioning for reliable and deterministic SoS applications, as well as, distributed algorithms for the discovery, optimized selection, and admission of service provisions are introduced. The proposed models will result in a two-step admission control algorithm with short- and long-term admissions based on schedulabiliy tests, resulting in service provisions between constituent systems. Furthermore, this article will investigate the integration of cloud resources for the on-demand instantiation of services. The models and the service coordination are evaluated in a use case from the health-care domain, which investigates the execution time and the scalability of the service coordination.