Timed Failure Logic Analysis in a Model-Driven Engineering approach

A complex System of Systems, integrating several hardware and software components in the holistic perspective of providing an emergent behaviour and operating within business-critical contexts, aims at affording contrasting requirements of reliability and complexity in delivered functions and quality of services by supporting system evolution and adaptation over time. This dissertation contributes to the area of Model-Driven Engineering (MDE), proposing a model-driven approach supporting timed failure logic analysis of complex Cyber-Physical Systems (CPS) in business-critical scenarios. The research defines a meta-model joining structural information about system architectures with their failure logic, decoupling representations of communication interfaces from those of failure propagation. The meta-model also supports runtime evolution (which can be very fast in the case of complex CPS) of concrete systems by enabling the configuration of product lines, capable of representing multiple variation points of a component, supporting continuous adaptation of offered products and services to business or customer needs. The meta-model enables a round-trip engineering process through the definition of a set of transformation rules, supporting the automated and correct-by-construction initialisation of meta-model instances starting from SysML Block Definition Diagrams for system specification and stochastic Fault Trees for timed failure logic, thus activating co-evolution mechanisms propagating external manual modifications, applied on meta-model instances, directly to the adopted structural and reliability artefacts. At the same time, a set of transformation rules has been defined so as to enable the automated generation of Stochastic Time Petri Nets (STPN) from meta-model instances, thus supporting quantitative evaluation of the imed failure logic. The MDE approach is demonstrated on the case study of a CPS operating in a Smart City environment, evaluating at design time different configurations of the system with respect to the reliability of its cyber-side. The research also addresses the design and the prototypical implementation of a tool offered both as-a-service and as a Java API.