  To evaluate the robustness gain of Bayesian neural networks on image
classification tasks, we perform input perturbations, and adversarial attacks
to the state-of-the-art Bayesian neural networks, with a benchmark CNN model as
reference. The attacks are selected to simulate signal interference and
cyberattacks towards CNN-based machine learning systems. The result shows that
a Bayesian neural network achieves significantly higher robustness against
adversarial attacks generated against a deterministic neural network model,
without adversarial training. The Bayesian posterior can act as the safety
precursor of ongoing malicious activities. Furthermore, we show that the
stochastic classifier after the deterministic CNN extractor has sufficient
robustness enhancement rather than a stochastic feature extractor before the
stochastic classifier. This advises on utilizing stochastic layers in building
decision-making pipelines within a safety-critical domain.
