TSFool: Crafting Highly-Imperceptible Adversarial Time Series through Multi-Objective Attack

Fuente: arXiv
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Main Authors: Wang, Yanyun, Du, Dehui, Hu, Haibo, Liang, Zi, Liu, Yuanhao
Format: Preprint
Published: 2022
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author Wang, Yanyun
Du, Dehui
Hu, Haibo
Liang, Zi
Liu, Yuanhao
author_facet Wang, Yanyun
Du, Dehui
Hu, Haibo
Liang, Zi
Liu, Yuanhao
contents Recent years have witnessed the success of recurrent neural network (RNN) models in time series classification (TSC). However, neural networks (NNs) are vulnerable to adversarial samples, which cause real-life adversarial attacks that undermine the robustness of AI models. To date, most existing attacks target at feed-forward NNs and image recognition tasks, but they cannot perform well on RNN-based TSC. This is due to the cyclical computation of RNN, which prevents direct model differentiation. In addition, the high visual sensitivity of time series to perturbations also poses challenges to local objective optimization of adversarial samples. In this paper, we propose an efficient method called TSFool to craft highly-imperceptible adversarial time series for RNN-based TSC. The core idea is a new global optimization objective known as "Camouflage Coefficient" that captures the imperceptibility of adversarial samples from the class distribution. Based on this, we reduce the adversarial attack problem to a multi-objective optimization problem that enhances the perturbation quality. Furthermore, to speed up the optimization process, we propose to use a representation model for RNN to capture deeply embedded vulnerable samples whose features deviate from the latent manifold. Experiments on 11 UCR and UEA datasets showcase that TSFool significantly outperforms six white-box and three black-box benchmark attacks in terms of effectiveness, efficiency and imperceptibility from various perspectives including standard measure, human study and real-world defense.
format Preprint
id arxiv_https___arxiv_org_abs_2209_06388
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle TSFool: Crafting Highly-Imperceptible Adversarial Time Series through Multi-Objective Attack
Wang, Yanyun
Du, Dehui
Hu, Haibo
Liang, Zi
Liu, Yuanhao
Machine Learning
Cryptography and Security
I.2.0; I.5.0
Recent years have witnessed the success of recurrent neural network (RNN) models in time series classification (TSC). However, neural networks (NNs) are vulnerable to adversarial samples, which cause real-life adversarial attacks that undermine the robustness of AI models. To date, most existing attacks target at feed-forward NNs and image recognition tasks, but they cannot perform well on RNN-based TSC. This is due to the cyclical computation of RNN, which prevents direct model differentiation. In addition, the high visual sensitivity of time series to perturbations also poses challenges to local objective optimization of adversarial samples. In this paper, we propose an efficient method called TSFool to craft highly-imperceptible adversarial time series for RNN-based TSC. The core idea is a new global optimization objective known as "Camouflage Coefficient" that captures the imperceptibility of adversarial samples from the class distribution. Based on this, we reduce the adversarial attack problem to a multi-objective optimization problem that enhances the perturbation quality. Furthermore, to speed up the optimization process, we propose to use a representation model for RNN to capture deeply embedded vulnerable samples whose features deviate from the latent manifold. Experiments on 11 UCR and UEA datasets showcase that TSFool significantly outperforms six white-box and three black-box benchmark attacks in terms of effectiveness, efficiency and imperceptibility from various perspectives including standard measure, human study and real-world defense.
title TSFool: Crafting Highly-Imperceptible Adversarial Time Series through Multi-Objective Attack
topic Machine Learning
Cryptography and Security
I.2.0; I.5.0
url https://arxiv.org/abs/2209.06388