DAVIDSTUTZ

Updated Pre-Print “Bit Error Robustness for Energy-Efficient DNN Accelerators “

Recently, deep neural network (DNN) accelerators have received considerable attention due to reduced cost and energy compared to mainstream GPUs. In order to further reduce energy consumption, the included memory (storing weights and intermediate computations) is operated at low voltage. However, this causes bit errors in memory cells, directly impacting the stored (quantized) DNN weights. This results in a significant decrease in CNN accuracy. In this paper, we tackle the problem of DNN robustness against random bit errors. By using a robust fixed-point quantization, training with aggressive weight clipping as regularization and injecting random bit errors during training, we increase robustness significantly, allowing energy-efficient DNN accelerators.

ARTICLE

The code for our paper on adversarial patch training on location-optimized adversarial patches is now available on GitHub. The repository includes a PyTorch implementation of our adversarial patch attack with location optimization as well as an adversarial training routine. The experiments on Cifar10 and GTSRB presented in the paper can easily be reproduced.

What Lp Adversarial Examples make Sense on Common Vision Datasets?

Adversarial examples are intended to be imperceptible perturbations that cause mis-classification while not changing the true class. Still, there is no consensus on what changes are considered imperceptible or when the true class actually changes — or is not recognizable anymore. In this article, I want to explore what levels of $L_\infty$, $L_0$ and $L_1$ adversarial noise actually make sense on popular computer vision datasets such as MNIST, Fashion-MNIST, SVHN or Cifar10.

ARTICLE

Confidence-calibrated adversarial training (CCAT) addresses two problems when training on adversarial examples: the lack of robustness against adversarial examples unseen during training, and the reduced (clean) accuracy. In particular, CCAT biases the model towards predicting low-confidence on adversarial examples such that adversarial examples can be rejected by confidence thresholding. In this article, I want to share the slides of the corresponding ICML talk.

ARTICLE

Our paper on confidence-calibrated adversarial training was accepted at ICML’20. In the revised paper, the proposed confidence-calibrated adversarial training tackles the problem of obtaining robustness that generalizes to attacks not seen during training. This is achieved by biasing the network towards low-confidence predictions on adversarial examples and rejecting these low-confidence examples at test time. This article gives a short abstract and includes paper and code.

ArXiv Pre-Print “On Mitigating Random and Adversarial Bit Errors”

Deep neural network (DNN) accelerators are specialized hardware for inference and have received considerable attention in the past years. Here, in order to reduce energy consumption, these accelerators are often operated at low voltage which causes the included accelerator memory to become unreliable. Additionally, recent work demonstrated attacks targeting individual bits in memory. The induced bit errors in both cases can cause significantly reduced accuracy of DNNs. In this paper, we tackle both random (due to low-voltage) and adversarial bit errors in DNNs. By explicitly taking such errors into account during training, wecan improve robustness significantly.

Illustrating (Convolutional) Neural Networks in LaTeX with TikZ

Many papers and theses provide high-level overviews of the proposed methods. Nowadays, in computer vision, natural language processing or similar research areas strongly driven by deep learning, these illustrations commonly include architectures of the used (convolutional) neural network. In this article, I want to provide a collection of examples using LaTeX and TikZ to produce nice figures of (convolutional) neural networks. All the discussed examples can also be found on GitHub.

ARTICLE

While robustness against imperceptible adversarial examples is well-studied, robustness against visible adversarial perturbations such as adversarial patches is poorly understood. In this pre-print, we present a practical approach to obtain adversarial patches while actively optimizing their location within the image. On Cifar10 and GTSRB, we show that adversarial training on these location-optimized adversarial patches improves robustness significantly while not reducing accuracy.

Implementing Custom PyTorch Tensor Operations in C and CUDA

PyTorch, alongside TensorFlow, has become standard among deep learning researchers and practitioners. While PyTorch provides a large variety in terms of tensor operations or deep learning layers, some specialized operations still need to be implemented manually. In cases where runtime is crucial, this should be done in C or CUDA for supporting both CPU and GPU computation. In this article, I want to provide a simple example and framework for extending PyTorch with custom C and CUDA operations using CFFI for Python and CuPy.

Adversarial Training Has Higher Sample Complexity

Training on adversarial examples generated on-the-fly, so-called adversarial training, improves robustness against adversarial examples while incurring a significant drop in accuracy. This apparent trade-off between robustness and accuracy has been observed on many datasets and is argued to be inherent to adversarial training — or even unavoidable. In this article, based on my recent CVPR’19 paper, I show experimental results indicating that adversarial training can achieve the same accuracy as normal training, if more training examples are available. This suggests that adversarial training has higher sample complexity.