Supporting model-based safety analysis for safety-critical IoT systems

Dependability is regarded as the ability of the system to provide services that can be trusted within a specific period. As the complexity and heterogeneity of Internet of Things (IoT) systems rise, so does the possibility of errors and failure. Early safety analysis not only reduces the cost of late failure but also makes it easier to trace and determine the source of the failure beforehand in case something goes wrong. In this paper, we present an early safety analysis approach based on Failure-Logic Analysis (FLA) and Fault-Tree Analysis (FTA) for safety-critical IoT systems. The safety analysis infrastructure, supported by the CHESSIoT tool, takes into account the system-level physical architecture model annotated with the component's failure logic properties to perform different kinds of automated failure analyses. In addition to its ability to generate the system Fault-Trees (FTs), the new FTA analysis approach automatically performs qualitative and quantitative analyses which include the elimination of redundant events, unnecessary failure paths, as well as automatic probabilistic calculation of the undesired events. To assess the effectiveness of the approach, a comparative study between our propose approach with 19 existing approaches in both academia and industry was conducted showcasing its contribution to the state of the art. Finally, a Patient Monitoring System (PMS) use case has been developed to demonstrate the capabilities of the supporting CHESSIoT tool, and the results are thoroughly presented.