  Adversarial machine learning (AML) studies attacks that can fool machine
learning algorithms into generating incorrect outcomes as well as the defenses
against worst-case attacks to strengthen model robustness. Specifically for
image classification, it is challenging to understand adversarial attacks due
to their use of subtle perturbations that are not human-interpretable, as well
as the variability of attack impacts influenced by diverse methodologies,
instance differences, and model architectures. Through a design study with AML
learners and teachers, we introduce AdvEx, a multi-level interactive
visualization system that comprehensively presents the properties and impacts
of evasion attacks on different image classifiers for novice AML learners. We
quantitatively and qualitatively assessed AdvEx in a two-part evaluation
including user studies and expert interviews. Our results show that AdvEx is
not only highly effective as a visualization tool for understanding AML
mechanisms, but also provides an engaging and enjoyable learning experience,
thus demonstrating its overall benefits for AML learners.
