Run-Time Monitoring of Self-Adaptive Systems to Detect N-way Feature Interactions and their Causes

The validity of systems at run time depends on the features included in those systems operating as specified. However, when feature interactions occur, the specifications no longer reflect the state of the run-time system due to the conflict. While methods exist to detect feature interactions at design time, conflicts that cause features to fail may still arise when new detected feature interactions are considered unreachable, new features are added, or an exhaustive design-time detection approach is impractical due to computational costs. This paper introduces Thoosa, an approach for using models at run time to detect features that can fail due to n-way feature interactions at run time and thereby trigger mitigating adaptations and/or updates to the requirements. We illustrate our approach by applying Thoosa to an industry-based automotive braking system comprising multiple subsystems.