Ontology-based runtime reconfiguration of distributed embedded real-time systems

Embedded real-time systems with dynamic resource management capabilities are able to adapt to changing resource requirements, resource availability, the occurrence of faults and environmental changes. This enables better resource utilization, more flexibility and increased dependability. Depending on the application domain, reconfiguration decisions must be found and applied within temporal bounds. Although semantic techniques are used to react to unexpected events in standard IT systems, they exhibit a computational complexity and temporal unpredictability that is not suitable for real-time systems. This paper describes a temporally predictable framework for reconfigurable embedded real-time systems. It uses a service-oriented approach to dynamically reconfigure component interactions. Knowledge about the system structure and semantics is provided in a system ontology with relevant information for embedded realtime systems (e.g., transfer delay times, accuracy of relations). The ontology allows to automatically generate service substitutes by exploiting implicit redundancy in the system. Furthermore, an algorithm is presented that searches the ontology for semantically equivalent implementations of failed services. The process of substitution search and substitute service generation is demonstrated with an example from the automotive domain.