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Hyperparameter Learning Under Data Poisoning: Analysis of the Influence of Regularization via Multiobjective Bilevel Optimization

delete2024-11-01
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OA
AI
J
Javier Carnerero-Cano *
L
Luis Muñoz-González
P
Phillippa Spencer
E
Emil Lupu
DOI:10.1109/TNNLS.2023.3291648delete
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Abstract

Abstract

En 中文
Machine learning (ML) algorithms are vulnerable to poisoning attacks, where a fraction of the training data is manipulated to deliberately degrade the algorithms' performance. Optimal attacks can be formulated as bilevel optimization problems and help to assess their robustness in worst case scenarios. We show that current approaches, which typically assume that hyperparameters remain constant, lead to an overly pessimistic view of the algorithms' robustness and of the impact of regularization. We propose a novel optimal attack formulation that considers the effect of the attack on the hyperparameters and models the attack as a multiobjective bilevel optimization problem. This allows us to formulate optimal attacks, learn hyperparameters, and evaluate robustness under worst case conditions. We apply this attack formulation to several ML classifiers using L-2 and L-1 regularization. Our evaluation on multiple datasets shows that choosing an a priori constant value for the regularization hyperparameter can be detrimental to the performance of the algorithms. This confirms the limitations of previous strategies and evidences the benefits of using L-2 and L-1 regularization to dampen the effect of poisoning attacks, when hyperparameters are learned using a small trusted dataset. Additionally, our results show that the use of regularization plays an important robustness and stability role in complex models, such as deep neural networks (DNNs), where the attacker can have more flexibility to manipulate the decision boundary.
Keywords:
Training
Robustness
Optimization
Machine learning algorithms
Classification algorithms
Training data
Toxicology
Adversarial machine learning (ML)
bilevel optimization
data poisoning attacks
hyperparameter optimization
regularization

Journal

IEEE Transactions on Neural Networks and Learning Systems cover
IEEE Transactions on Neural Networks and Learning Systems
IF:
8.9
Papers:
7.5K
Citations:
7.2W

Organization

D
defence science and technology laboratory
Scholars:
720
Papers: 619
Citations: 4
I
Imperial College London
Scholars:
8.3W
Papers: 7.3W
Citations: 11.1W