Title
Characterizing the Shape of Activation Space in Deep Neural Networks.
Abstract
The representations learned by deep neural networks are difficult to interpret in part due to their large parameter space and the complexities introduced by their multi-layer structure. We introduce a method for computing persistent homology over the graphical activation structure of neural networks, which provides access to the task-relevant substructures activated throughout the network for a given input. This topological perspective provides unique insights into the distributed representations encoded by neural networks in terms of the shape of their activation structures. We demonstrate the value of this approach by showing an alternative explanation for the existence of adversarial examples. By studying the topology of network activations across multiple architectures and datasets, we find that adversarial perturbations do not add activations that target the semantic structure of the adversarial class as previously hypothesized. Rather, adversarial examples are explainable as alterations to the dominant activation structures induced by the original image, suggesting the class representations learned by deep networks are problematically sparse on the input space.
Year
DOI
Venue
2019
10.1109/ICMLA.2019.00254
arXiv: Learning
Field
DocType
Citations 
Persistent homology,Theoretical computer science,Artificial intelligence,Parameter space,Artificial neural network,Mathematics,Deep neural networks,Machine learning,Adversarial system
Conference
0
PageRank 
References 
Authors
0.34
0
3
Name
Order
Citations
PageRank
Thomas Gebhart100.34
Paul R. Schrater214122.71
Alan Hylton321.18