Safeguarding End-to-End Service Continuity when Connecting Safety-Critical Systems to the Cloud

Safety-critical cyber-physical systems (CPS) are increasingly connected to the cloud in order to use smart data analytics and provide easy-to-install and easy-to-update solutions. Furthermore, mission-critical applications are considered for off-loading to the cloud. Cloud environments however do not generally provide for safety-critical hardware and software to ensure high availability and reliability. Therefore, measures have to be taken to safeguard service continuity when off-loading mission-critical applications to the cloud. In this paper, a three-stage design methodology to safeguard end-to-end service continuity is proposed. Based on an analysis of potential service disruptions, service continuity monitoring and mitigation options are identified. Then these became a part of a service continuity solution by instantiating a device-edge-cloud reference architecture for safety-critical CPS solutions and using safety-critical systems design patterns. This methodology is evaluated with a cloud-connected advanced imaging workflow for an image-guided treatment (IGT) system in an hospital.