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arXiv 1209.1322cs.CRcs.DB
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地理空间数据的差分私有格网

Differentially Private Grids for Geospatial Data

Wahbeh Qardaji, Weining Yang, Ninghui Li

摘要:

在本文中,我们解决的问题,构建一个差异化的私人概要的二维数据集,如地理空间数据集。当前最先进的方法通过执行数据域的递归二进制分区并构造分区的层次结构来工作。我们发现,基于分区的概要方法的关键挑战在于选择正确的分区粒度来平衡噪声误差和非均匀性误差。我们研究了均匀网格的方法,它适用于一个等宽度的网格上的数据域的一定大小,然后在网格单元上发出独立的计数查询。这种方法在文献中没有得到关注,可能是因为没有好的方法来选择网格大小是已知的。在分析这两种误差的基础上,提出了一种选择网格尺寸的方法。实验结果验证了我们的方法,并表明,这种方法执行以及,往往倍优于,国家的最先进的方法。我们进一步介绍了一种新的自适应网格方法。自适应网格方法在数据集上放置粗粒度网格,然后根据其噪声计数进一步划分每个单元。然后,这两个级别的分区都用于回答对数据集的查询。该方法利用了在密集区域上具有更细粒度分区的需要,并且同时在稀疏区域上具有粗分区。通过对真实世界数据集的大量实验,我们表明这种方法始终显着优于均匀网格方法和其他最先进的方法。

英文摘要:

In this paper, we tackle the problem of constructing a differentially private synopsis for two-dimensional datasets such as geospatial datasets. The current state-of-the-art methods work by performing recursive binary partitioning of the data domains, and constructing a hierarchy of partitions. We show that the key challenge in partition-based synopsis methods lies in choosing the right partition granularity to balance the noise error and the non-uniformity error. We study the uniform-grid approach, which applies an equi-width grid of a certain size over the data domain and then issues independent count queries on the grid cells. This method has received no attention in the literature, probably due to the fact that no good method for choosing a grid size was known. Based on an analysis of the two kinds of errors, we propose a method for choosing the grid size. Experimental results validate our method, and show that this approach performs as well as, and often times better than, the state-of-the-art methods. We further introduce a novel adaptive-grid method. The adaptive grid method lays a coarse-grained grid over the dataset, and then further partitions each cell according to its noisy count. Both levels of partitions are then used in answering queries over the dataset. This method exploits the need to have finer granularity partitioning over dense regions and, at the same time, coarse partitioning over sparse regions. Through extensive experiments on real-world datasets, we show that this approach consistently and significantly outperforms the uniform-grid method and other state-of-the-art methods.

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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