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As data gathering grows easier, and as researchers discover new ways to interpret data, streaming-data algorithms have become essential in many elds. Data stream computation precludes algorithms that require random access or large memory. In this paper, we consider the problem of clustering data streams, which is important in the analysis a variety of(More)
We study clustering under the data stream model of computation where: given a sequence of points, the objective is to maintain a consistently good clustering of the sequence observed so far, using a small amount of memory and time. The data stream model is relevant to new classes of applications involving massive data sets, such as web click stream analysis(More)
The data stream model has recently attracted attention for its applicability to numerous types of data, including telephone records, web documents and clickstreams. For analysis of such data, the ability to process the data in a single pass, or a small number of passes, while using little memory, is crucial. We describe such a streaming algorithm that(More)
The question of how to publish an anonymized search log was brought to the forefront by a well-intentioned, but privacy-unaware AOL search log release. Since then a series of ad-hoc techniques have been proposed in the literature, though none are known to be provably private. In this paper, we take a major step towards a solution: we show how queries,(More)
Given a data set consisting of private information about individuals, we consider the <i>online query auditing problem:</i> given a sequence of queries that have already been posed about the data, their corresponding answers -- where each answer is either the true answer or "denied" (in the event that revealing the answer compromises privacy) -- and given a(More)
Social networks are ubiquitous. The discovery of close-knit clusters in these networks is of fundamental and practical interest. Existing clustering criteria are limited in that clusters typically do not overlap, all vertices are clustered and/or external sparsity is ignored. We introduce a new criterion that overcomes these limitations by combining(More)
We consider the online query auditing problem for statistical databases. Given a stream of aggregate queries posed over sensitive data, when should queries be denied in order to protect the privacy of individuals? We construct efficient auditors for max queries and bags of max and min queries in both the partial and full disclosure settings. Our algorithm(More)
A version space is a collection of concepts consistent with a given set of positive and negative examples. Mitchell [Mit82] proposed representing a version space by its boundary sets: the maximally general (G) and maximally specific consistent concepts (S). For many simple concept classes, the size of G and S is known to grow exponentially in the number of(More)
Buggy software is a reality and automated techniques for discovering bugs are highly desirable. A specification describes the correct behavior of a program. For example, a file must eventually be closed once it has been opened. Specifications are learned by finding patterns in normal program execution traces versus erroneous ones. With more traces, more(More)