Machine Unlearning

Report on Current Developments in Machine Unlearning Research

General Direction of the Field

The field of machine unlearning is rapidly evolving, driven by the increasing need for data privacy, model robustness, and compliance with regulatory requirements. Recent advancements are focusing on developing efficient and effective methods for removing the influence of specific data points from trained models, while maintaining model utility. The research is particularly challenging for deep neural networks, which tend to memorize a significant portion of their training data.

One of the key directions in the field is the development of novel techniques that address the varying difficulty of unlearning individual training samples. Researchers are exploring ways to quantify and rank the difficulty of unlearning, which can help in designing more precise and efficient unlearning algorithms. This approach is crucial for understanding the broader feasibility of machine unlearning and for identifying the most challenging samples to unlearn.

Another significant trend is the application of machine unlearning in federated learning settings. Federated unlearning methods aim to remove information from globally trained models without harming the model performance on the remaining data. These methods are particularly important for decentralized data sources, where the removal of a participant and their related information poses significant challenges. Recent work has introduced efficient frameworks that do not require retraining or heavy computation, making them suitable for practical deployment.

In addition to these, there is a growing interest in graph unlearning, which focuses on erasing the influence of specific data on trained Graph Neural Network (GNN) models. This area is particularly challenging due to the complex relationships between nodes in a graph. Researchers are developing data-centric solutions that pre-condense the original graph into a small yet utility-preserving dataset, enabling efficient unlearning without accessing the deleted data.

Overall, the field is moving towards more efficient, precise, and practical solutions that address the unique challenges of unlearning in various settings, including deep neural networks, federated learning, and graph neural networks.

Noteworthy Papers

  • Interleaved Ensemble Unlearning (IEU): Introduces a novel method for finetuning clean Vision Transformers (ViTs) on backdoored datasets, demonstrating effectiveness against state-of-the-art backdoor attacks.

  • Deep Unlearn Benchmark: Provides a comprehensive evaluation of machine unlearning methods across various models and datasets, highlighting the importance of proper hyperparameter selection and better baselines.

  • ConDa: Fast Federated Unlearning: Introduces an efficient federated unlearning framework that outperforms state-of-the-art methods by at least 100x, emphasizing non-IID settings and robustness against attacks.

  • TCGU: Data-centric Graph Unlearning: Proposes a novel approach for zero-glance graph unlearning, achieving superior performance in terms of model utility, unlearning efficiency, and efficacy.

  • FUCRT: Federated Unlearning via Class-Aware Representation Transformation: Achieves complete erasure of unlearning classes while maintaining or improving performance on remaining classes, outperforming state-of-the-art baselines in both IID and Non-IID settings.

Sources

Using Interleaved Ensemble Unlearning to Keep Backdoors at Bay for Finetuning Vision Transformers

Deep Unlearn: Benchmarking Machine Unlearning

Towards Understanding the Feasibility of Machine Unlearning

ConDa: Fast Federated Unlearning with Contribution Dampening

Machine Unlearning in Forgettability Sequence

TCGU: Data-centric Graph Unlearning based on Transferable Condensation

Forgetting Through Transforming: Enabling Federated Unlearning via Class-Aware Representation Transformation

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