Surrogate Neural Networks Local Stability for Aircraft Predictive Maintenance
This work addresses verification needs for deploying neural networks in safety-critical aerospace applications, representing an incremental improvement in verification methodology.
The paper tackles the challenge of verifying surrogate neural networks for safety-critical aircraft predictive maintenance, specifically assessing their local stability to input noise. The authors demonstrate that combining verification methods in a pipeline reduces runtime for property assessment.
Surrogate Neural Networks are nowadays routinely used in industry as substitutes for computationally demanding engineering simulations (e.g., in structural analysis). They allow to generate faster predictions and thus analyses in industrial applications e.g., during a product design, testing or monitoring phases. Due to their performance and time-efficiency, these surrogate models are now being developed for use in safety-critical applications. Neural network verification and in particular the assessment of their robustness (e.g., to perturbations) is the next critical step to allow their inclusion in real-life applications and certification. We assess the applicability and scalability of empirical and formal methods in the context of aircraft predictive maintenance for surrogate neural networks designed to predict the stress sustained by an aircraft part from external loads. The case study covers a high-dimensional input and output space and the verification process thus accommodates multi-objective constraints. We explore the complementarity of verification methods in assessing the local stability property of such surrogate models to input noise. We showcase the effectiveness of sequentially combining methods in one verification 'pipeline' and demonstrate the subsequent gain in runtime required to assess the targeted property.