Sampling hidden objects using nearest-neighbor oracles.

Given an unknown set of objects embedded in the Euclidean plane and a nearest-neighbor oracle, how to estimate the set size and other properties of the objects? In this paper we address this problem. We propose an efficient method that uses the Voronoi partitioning of the space by the objects and a nearest-neighbor oracle. Our method can be used in the hidden web/databases context where the goal is to estimate the number of certain objects of interest. Here, we assume that each object has a geographic location and the nearest-neighbor oracle can be realized by applications such as maps, local, or store-locator APIs. We illustrate the performance of our method on several real-world datasets.