Search Results for author: Jiefeng Chen

Found 24 papers, 13 papers with code

Reinforcing Adversarial Robustness using Model Confidence Induced by Adversarial Training

no code implementations ICML 2018 Xi Wu, Uyeong Jang, Jiefeng Chen, Lingjiao Chen, Somesh Jha

In this paper we study leveraging confidence information induced by adversarial training to reinforce adversarial robustness of a given adversarially trained model.

Adversarial Robustness

ReabsNet: Detecting and Revising Adversarial Examples

no code implementations21 Dec 2017 Jiefeng Chen, Zihang Meng, Changtian Sun, Wei Tang, Yinglun Zhu

Though deep neural network has hit a huge success in recent studies and applica- tions, it still remains vulnerable to adversarial perturbations which are imperceptible to humans.

General Classification

Towards Understanding Limitations of Pixel Discretization Against Adversarial Attacks

1 code implementation20 May 2018 Jiefeng Chen, Xi Wu, Vaibhav Rastogi, YIngyu Liang, Somesh Jha

We analyze our results in a theoretical framework and offer strong evidence that pixel discretization is unlikely to work on all but the simplest of the datasets.

Concise Explanations of Neural Networks using Adversarial Training

1 code implementation ICML 2020 Prasad Chalasani, Jiefeng Chen, Amrita Roy Chowdhury, Somesh Jha, Xi Wu

Our first contribution is a theoretical exploration of how these two properties (when using attributions based on Integrated Gradients, or IG) are related to adversarial training, for a class of 1-layer networks (which includes logistic regression models for binary and multi-class classification); for these networks we show that (a) adversarial training using an $\ell_\infty$-bounded adversary produces models with sparse attribution vectors, and (b) natural model-training while encouraging stable explanations (via an extra term in the loss function), is equivalent to adversarial training.

Multi-class Classification

Robust Attribution Regularization

1 code implementation NeurIPS 2019 Jiefeng Chen, Xi Wu, Vaibhav Rastogi, YIngyu Liang, Somesh Jha

An emerging problem in trustworthy machine learning is to train models that produce robust interpretations for their predictions.

AI-GAN: Attack-Inspired Generation of Adversarial Examples

1 code implementation6 Feb 2020 Tao Bai, Jun Zhao, Jinlin Zhu, Shoudong Han, Jiefeng Chen, Bo Li, Alex Kot

Deep neural networks (DNNs) are vulnerable to adversarial examples, which are crafted by adding imperceptible perturbations to inputs.

GRAPHITE: Generating Automatic Physical Examples for Machine-Learning Attacks on Computer Vision Systems

1 code implementation17 Feb 2020 Ryan Feng, Neal Mangaokar, Jiefeng Chen, Earlence Fernandes, Somesh Jha, Atul Prakash

We address three key requirements for practical attacks for the real-world: 1) automatically constraining the size and shape of the attack so it can be applied with stickers, 2) transform-robustness, i. e., robustness of a attack to environmental physical variations such as viewpoint and lighting changes, and 3) supporting attacks in not only white-box, but also black-box hard-label scenarios, so that the adversary can attack proprietary models.

BIG-bench Machine Learning General Classification +1

Robust Out-of-distribution Detection for Neural Networks

1 code implementation AAAI Workshop AdvML 2022 Jiefeng Chen, Yixuan Li, Xi Wu, YIngyu Liang, Somesh Jha

Formally, we extensively study the problem of Robust Out-of-Distribution Detection on common OOD detection approaches, and show that state-of-the-art OOD detectors can be easily fooled by adding small perturbations to the in-distribution and OOD inputs.

Out-of-Distribution Detection Out of Distribution (OOD) Detection

Representation Bayesian Risk Decompositions and Multi-Source Domain Adaptation

no code implementations22 Apr 2020 Xi Wu, Yang Guo, Jiefeng Chen, YIngyu Liang, Somesh Jha, Prasad Chalasani

Recent studies provide hints and failure examples for domain invariant representation learning, a common approach for this problem, but the explanations provided are somewhat different and do not provide a unified picture.

Domain Adaptation Representation Learning

ATOM: Robustifying Out-of-distribution Detection Using Outlier Mining

1 code implementation26 Jun 2020 Jiefeng Chen, Yixuan Li, Xi Wu, YIngyu Liang, Somesh Jha

We show that, by mining informative auxiliary OOD data, one can significantly improve OOD detection performance, and somewhat surprisingly, generalize to unseen adversarial attacks.

Out-of-Distribution Detection Out of Distribution (OOD) Detection

Informative Outlier Matters: Robustifying Out-of-distribution Detection Using Outlier Mining

no code implementations28 Sep 2020 Jiefeng Chen, Yixuan Li, Xi Wu, YIngyu Liang, Somesh Jha

We show that, by mining informative auxiliary OOD data, one can significantly improve OOD detection performance, and somewhat surprisingly, generalize to unseen adversarial attacks.

Out-of-Distribution Detection Out of Distribution (OOD) Detection

Test-Time Adaptation and Adversarial Robustness

no code implementations1 Jan 2021 Xi Wu, Yang Guo, Tianqi Li, Jiefeng Chen, Qicheng Lao, YIngyu Liang, Somesh Jha

On the positive side, we show that, if one is allowed to access the training data, then Domain Adversarial Neural Networks (${\sf DANN}$), an algorithm designed for unsupervised domain adaptation, can provide nontrivial robustness in the test-time maximin threat model against strong transfer attacks and adaptive fixed point attacks.

Adversarial Robustness Test-time Adaptation +1

Towards Adversarial Robustness via Transductive Learning

no code implementations15 Jun 2021 Jiefeng Chen, Yang Guo, Xi Wu, Tianqi Li, Qicheng Lao, YIngyu Liang, Somesh Jha

Compared to traditional "test-time" defenses, these defense mechanisms "dynamically retrain" the model based on test time input via transductive learning; and theoretically, attacking these defenses boils down to bilevel optimization, which seems to raise the difficulty for adaptive attacks.

Adversarial Robustness Bilevel Optimization +1

Detecting Errors and Estimating Accuracy on Unlabeled Data with Self-training Ensembles

1 code implementation NeurIPS 2021 Jiefeng Chen, Frederick Liu, Besim Avci, Xi Wu, YIngyu Liang, Somesh Jha

This observation leads to two challenging tasks: (1) unsupervised accuracy estimation, which aims to estimate the accuracy of a pre-trained classifier on a set of unlabeled test inputs; (2) error detection, which aims to identify mis-classified test inputs.

Towards Evaluating the Robustness of Neural Networks Learned by Transduction

1 code implementation ICLR 2022 Jiefeng Chen, Xi Wu, Yang Guo, YIngyu Liang, Somesh Jha

There has been emerging interest in using transductive learning for adversarial robustness (Goldwasser et al., NeurIPS 2020; Wu et al., ICML 2020; Wang et al., ArXiv 2021).

Adversarial Robustness Bilevel Optimization +1

Towards Efficiently Evaluating the Robustness of Deep Neural Networks in IoT Systems: A GAN-based Method

no code implementations19 Nov 2021 Tao Bai, Jun Zhao, Jinlin Zhu, Shoudong Han, Jiefeng Chen, Bo Li, Alex Kot

Through extensive experiments, AI-GAN achieves high attack success rates, outperforming existing methods, and reduces generation time significantly.

Revisiting Adversarial Robustness of Classifiers With a Reject Option

no code implementations AAAI Workshop AdvML 2022 Jiefeng Chen, Jayaram Raghuram, Jihye Choi, Xi Wu, YIngyu Liang, Somesh Jha

Motivated by this metric, we propose novel loss functions and a robust training method -- \textit{stratified adversarial training with rejection} (SATR) -- for a classifier with reject option, where the goal is to accept and correctly-classify small input perturbations, while allowing the rejection of larger input perturbations that cannot be correctly classified.

Adversarial Robustness Image Classification

Concept-based Explanations for Out-Of-Distribution Detectors

1 code implementation4 Mar 2022 Jihye Choi, Jayaram Raghuram, Ryan Feng, Jiefeng Chen, Somesh Jha, Atul Prakash

Based on these metrics, we propose an unsupervised framework for learning a set of concepts that satisfy the desired properties of high detection completeness and concept separability, and demonstrate its effectiveness in providing concept-based explanations for diverse off-the-shelf OOD detectors.

Out of Distribution (OOD) Detection

The Trade-off between Universality and Label Efficiency of Representations from Contrastive Learning

1 code implementation28 Feb 2023 Zhenmei Shi, Jiefeng Chen, Kunyang Li, Jayaram Raghuram, Xi Wu, YIngyu Liang, Somesh Jha

foundation models) has recently become a prevalent learning paradigm, where one first pre-trains a representation using large-scale unlabeled data, and then learns simple predictors on top of the representation using small labeled data from the downstream tasks.

Contrastive Learning

Is forgetting less a good inductive bias for forward transfer?

no code implementations14 Mar 2023 Jiefeng Chen, Timothy Nguyen, Dilan Gorur, Arslan Chaudhry

We argue that the measure of forward transfer to a task should not be affected by the restrictions placed on the continual learner in order to preserve knowledge of previous tasks.

Continual Learning Image Classification +1

ASPEST: Bridging the Gap Between Active Learning and Selective Prediction

1 code implementation7 Apr 2023 Jiefeng Chen, Jinsung Yoon, Sayna Ebrahimi, Sercan Arik, Somesh Jha, Tomas Pfister

In this work, we introduce a new learning paradigm, active selective prediction, which aims to query more informative samples from the shifted target domain while increasing accuracy and coverage.

Active Learning

Stratified Adversarial Robustness with Rejection

1 code implementation2 May 2023 Jiefeng Chen, Jayaram Raghuram, Jihye Choi, Xi Wu, YIngyu Liang, Somesh Jha

We theoretically analyze the stratified rejection setting and propose a novel defense method -- Adversarial Training with Consistent Prediction-based Rejection (CPR) -- for building a robust selective classifier.

Adversarial Robustness Robust classification

Two Heads are Better than One: Towards Better Adversarial Robustness by Combining Transduction and Rejection

no code implementations27 May 2023 Nils Palumbo, Yang Guo, Xi Wu, Jiefeng Chen, YIngyu Liang, Somesh Jha

Nevertheless, under recent strong adversarial attacks (GMSA, which has been shown to be much more effective than AutoAttack against transduction), Goldwasser et al.'s work was shown to have low performance in a practical deep-learning setting.

Adversarial Robustness

Adaptation with Self-Evaluation to Improve Selective Prediction in LLMs

no code implementations18 Oct 2023 Jiefeng Chen, Jinsung Yoon, Sayna Ebrahimi, Sercan O Arik, Tomas Pfister, Somesh Jha

Large language models (LLMs) have recently shown great advances in a variety of tasks, including natural language understanding and generation.

Decision Making Natural Language Understanding +1

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