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arXiv 1606.03572cs.CR
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基于光滑灵敏度的差分私有随机决策森林

Differentially Private Random Decision Forests using Smooth Sensitivity

Sam Fletcher, Md Zahidul Islam

摘要:

我们提出了一种新的差异私有决策森林算法,可以最大限度地减少所需查询的数量和这些查询的敏感性。为此,我们构建了一个随机决策树的集合,除了在叶节点中找到多数类标签之外,避免查询私有数据。我们使用指数机制只输出类标签本身,而不是像当前最先进的方法那样使用计数查询来返回类计数。这大大降低了查询的敏感性-通常是几个数量级-这反过来又减少了为保护隐私而必须添加的噪声量。我们改进的灵敏度是通过使用“平滑灵敏度”来实现的,它考虑了查询中使用的特定数据,而不是假设最坏的情况。我们还扩展了随机决策树的最佳深度的工作,以处理连续的功能,而不仅仅是离散的功能。这一点以及其他几项改进,使我们能够创建一个差异化的私有决策森林,其预测能力远远高于当前最先进的技术。

英文摘要:

We propose a new differentially-private decision forest algorithm that minimizes both the number of queries required, and the sensitivity of those queries. To do so, we build an ensemble of random decision trees that avoids querying the private data except to find the majority class label in the leaf nodes. Rather than using a count query to return the class counts like the current state-of-the-art, we use the Exponential Mechanism to only output the class label itself. This drastically reduces the sensitivity of the query -- often by several orders of magnitude -- which in turn reduces the amount of noise that must be added to preserve privacy. Our improved sensitivity is achieved by using "smooth sensitivity", which takes into account the specific data used in the query rather than assuming the worst-case scenario. We also extend work done on the optimal depth of random decision trees to handle continuous features, not just discrete features. This, along with several other improvements, allows us to create a differentially private decision forest with substantially higher predictive power than the current state-of-the-art.

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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