Machine unlearning techniques, which involve retracting data records and reducing influence of said data on trained models, help with the user privacy protection objective but incur significant computational costs. Weight perturbation-based unlearning is a general approach, but it typically involves globally modifying the parameters. We propose fine-grained Top-K and Random-k parameters perturbed inexact machine unlearning strategies that address the privacy needs while keeping the computational costs tractable. In order to demonstrate the efficacy of our strategies we also tackle the challenge of evaluating the effectiveness of machine unlearning by considering the model's generalization performance across both unlearning and remaining data. To better assess the unlearning effect and model generalization, we propose novel metrics, namely, the forgetting rate and memory retention rate. However, for inexact machine unlearning, current metrics are inadequate in quantifying the degree of forgetting that occurs after unlearning strategies are applied. To address this, we introduce SPD-GAN, which subtly perturbs the distribution of data targeted for unlearning. Then, we evaluate the degree of unlearning by measuring the performance difference of the models on the perturbed unlearning data before and after the unlearning process. By implementing these innovative techniques and metrics, we achieve computationally efficacious privacy protection in machine learning applications without significant sacrifice of model performance. Furthermore, this approach provides a novel method for evaluating the degree of unlearning.

机器遗忘方法针对用户隐私保护目标有重要作用，但会带来大量计算成本。我们提出了细粒度 Top-K 和 Random-k 参数扰动的不精确机器遗忘策略，以在保持可计算性开销的同时满足隐私需求。我们还引入了评估机器遗忘效果和模型泛化能力的新指标——遗忘率和记忆保留率。通过实施这些创新技术和指标，我们在不显著牺牲模型性能的前提下实现了高效的隐私保护，并提供了一种评估遗忘程度的新方法。

通过细粒度模型参数扰动进行机器反学习