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arXiv 2603.09583cs.LG
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非参数变分差分隐私 via 嵌入参数裁剪

Nonparametric Variational Differential Privacy via Embedding Parameter Clipping

Idiap Research Institute(日内瓦研究所);EPFL(瑞士联邦理工学院)

Dina El Zein, Shashi Kumar, James Henderson

AI总结:

本文提出通过嵌入参数裁剪解决非参数变分差分隐私中潜在表示漂移问题,理论推导出后验均值、方差和混合权重约束,提升隐私-效用平衡。

摘要:

非参数变分信息瓶颈(NVIB)为构建隐私保护语言模型提供了基础,但学习的潜在表示可能进入高信息内容区域,导致隐私保障不足且训练不稳定。本文引入一种原理性的参数裁剪策略,从最小化Rényi散度(RD)上界的目标出发,推导出后验均值、方差和混合权重参数的理论约束。我们将该技术应用于基于NVIB的模型,并与无约束基线进行实证比较。结果表明,裁剪模型能更紧密地满足RD上界,意味着更强的隐私保护,同时在多个下游任务上表现更优。本文提出了一种简单有效的改进变分模型隐私-效用权衡的方法,使其更具鲁棒性和实用性。

英文摘要:

The nonparametric variational information bottleneck (NVIB) provides the foundation for nonparametric variational differential privacy (NVDP), a framework for building privacy-preserving language models. However, the learned latent representations can drift into regions with high information content, leading to poor privacy guarantees, but also low utility due to numerical instability during training. In this work, we introduce a principled parameter clipping strategy to directly address this issue. Our method is mathematically derived from the objective of minimizing the Rényi Divergence (RD) upper bound, yielding specific, theoretically grounded constraints on the posterior mean, variance, and mixture weight parameters. We apply our technique to an NVIB based model and empirically compare it against an unconstrained baseline. Our findings demonstrate that the clipped model consistently achieves tighter RD bounds, implying stronger privacy, while simultaneously attaining higher performance on several downstream tasks. This work presents a simple yet effective method for improving the privacy-utility trade-off in variational models, making them more robust and practical.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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