Graham Cormode

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We introduce a new sublinear space data structure—the count-min sketch—for summarizing data streams. Our sketch allows fundamental queries in data stream summarization such as point, range, and inner product queries to be approximately answered very quickly; in addition, it can be applied to solve several important problems in data streams such as finding(More)
When dealing with massive quantities of data, top-k queries are a powerful technique for returning only the k most relevant tuples for inspection, based on a scoring function. The problem of efficiently answering such ranking queries has been studied and analyzed extensively within traditional database settings. The importance of the top-k is perhaps even(More)
Most database management systems maintain statistics on the underlying relation. One of the important statistics is that of the "hot items" in the relation: those that appear many times (most frequently, or more than some threshold). For example, end-biased histograms keep the hot items as part of the histogram and are used in selectivity estimation. Hot(More)
Differential privacy has recently emerged as the de facto standard for private data release. This makes it possible to provide strong theoretical guarantees on the privacy and utility of released data. While it is well-understood how to release data based on counts and simple functions under this guarantee, it remains to provide general purpose techniques(More)
The edit distance between two strings <i>S</i> and <i>R</i> is defined to be the minimum number of character inserts, deletes, and changes needed to convert <i>R</i> to <i>S</i>. Given a text string <i>t</i> of length <i>n</i>, and a pattern string <i>p</i> of length <i>m</i>, informally, the string edit distance matching problem is to compute the smallest(More)
Emerging large-scale monitoring applications require continuous tracking of complex dataanalysis queries over collections of physicallydistributed streams. Effective solutions have to be simultaneously space/time efficient (at each remote monitor site), communication efficient (across the underlying communication network), and provide continuous,(More)
Monitoring and analyzing network traffic usage patterns is vital for managing IP Networks. An important problem is to provide network managers with information about changes in traffic, informing them about "what's new." Specifically, we focus on the challenge of finding significantly large differences in traffic: over time, between interfaces and between(More)
Monitoring is an issue of primary concern in current and next generation networked systems. For ex, the objective of sensor networks is to monitor their surroundings for a variety of different applications like atmospheric conditions, wildlife behavior, and troop movements among others. Similarly, monitoring in data networks is critical not only for(More)
Web 2.0 is a buzzword introduced in 2003–04 which is commonly used to encompass various novel phenomena on the World Wide Web. Although largely a marketing term, some of the key attributes associated with Web 2.0 include the growth of social networks, bi–directional communication, various ‘glue’ technologies, and significant diversity in content types. We(More)
Aggregation along hierarchies is a critical summary technique in a large variety of online applications including decision support, and network management (e.g., IP clustering, denial-of-service attack monitoring). Despite the amount of recent study that has been dedicated to online aggregation on sets (e.g., quantiles, hot items), surprisingly little(More)