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77
Survey of clustering data mining techniques
, 2002
"... Accrue Software, Inc. Clustering is a division of data into groups of similar objects. Representing the data by fewer clusters necessarily loses certain fine details, but achieves simplification. It models data by its clusters. Data modeling puts clustering in a historical perspective rooted in math ..."
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Cited by 247 (0 self)
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Accrue Software, Inc. Clustering is a division of data into groups of similar objects. Representing the data by fewer clusters necessarily loses certain fine details, but achieves simplification. It models data by its clusters. Data modeling puts clustering in a historical perspective rooted in mathematics, statistics, and numerical analysis. From a machine learning perspective clusters correspond to hidden patterns, the search for clusters is unsupervised learning, and the resulting system represents a data concept. From a practical perspective clustering plays an outstanding role in data mining applications such as scientific data exploration, information retrieval and text mining, spatial database applications, Web analysis, CRM, marketing, medical diagnostics, computational biology, and many others. Clustering is the subject of active research in several fields such as statistics, pattern recognition, and machine learning. This survey focuses on clustering in data mining. Data mining adds to clustering the complications of very large datasets with very many attributes of different types. This imposes unique
Constant InteractionTime Scatter/Gather Browsing of Very Large Document Collections
, 1993
"... The Scatter/Gather document browsing method uses fast document clustering to produce tableofcontentslike outlines of large document collections. Previous work [1] developed lineartime document clustering algorithms to establish the feasibility of this method over moderately large collections. How ..."
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Cited by 124 (5 self)
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The Scatter/Gather document browsing method uses fast document clustering to produce tableofcontentslike outlines of large document collections. Previous work [1] developed lineartime document clustering algorithms to establish the feasibility of this method over moderately large collections. However, even lineartime algorithms are too slow to support interactive browsing of very large collections such as Tipster, the DARPA standard text retrieval evaluation collection. We present a scheme that supports constant interactiontime Scatter /Gather of arbitrarily large collections after nearlinear time preprocessing. This involves the construction of a cluster hierarchy. A modification of Scatter /Gather employing this scheme, and an example of its use over the Tipster collection are presented. 1 Background Our previous work on Scatter/Gather [1] has shown that document clustering can be used as a firstclass tool for browsing large text collections. Browsing is distinguished from sea...
D.: Enriching Very Large Ontologies Using the WWW
 In: Proc. of 1st International Workshop on Ontology Learning (OL 2000). Held in Conjunction with the 14th European Conference on Artificial Intelligence (ECAI
, 2000
"... Abstract. This paper explores the possibility to exploit text on the world wide web in order to enrich the concepts in existing ontologies. First, a method to retrieve documents from the WWW related to a concept is described. These document collections are used 1) to construct topic signatures (list ..."
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Cited by 104 (5 self)
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Abstract. This paper explores the possibility to exploit text on the world wide web in order to enrich the concepts in existing ontologies. First, a method to retrieve documents from the WWW related to a concept is described. These document collections are used 1) to construct topic signatures (lists of topically related words) for each concept in WordNet, and 2) to build hierarchical clusters of the concepts (the word senses) that lexicalize a given word. The overall goal is to overcome two shortcomings of WordNet: the lack of topical links among concepts, and the proliferation of senses. Topic signatures are validated on a word sense disambiguation task with good results, which are improved when the hierarchical clusters are used. 1
Fast and Intuitive Clustering of Web Documents
 In Proceedings of the 3rd International Conference on Knowledge Discovery and Data Mining
, 1997
"... Conventional document retrieval systems (e.g., Alta Vista) return long lists of ranked documents in response to user queries. Recently, document clustering has been put forth as an alternative method of organizing retrieval results (Cutting et al. 1992). A person browsing the clusters can discover ..."
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Cited by 101 (2 self)
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Conventional document retrieval systems (e.g., Alta Vista) return long lists of ranked documents in response to user queries. Recently, document clustering has been put forth as an alternative method of organizing retrieval results (Cutting et al. 1992). A person browsing the clusters can discover patterns that could be overlooked in the traditional presentation. This paper describes two novel clustering methods that intersect the documents in a cluster to determine the set of words (or phrases) shared by all the documents in the cluster. We report on experiments that evaluate these intersectionbased clustering methods on collections of snippets returned from Web search engines. First, we show that wordintersection clustering produces superior clusters and does so faster than standard techniques. Second, we show that our O(n log n) time phraseintersection clustering method produces comparable clusters and does so more than two orders of magnitude faster than all methods tested. I...
Toward privacy in public databases
 In TCC
, 2005
"... Abstract. We initiate a theoretical study of the census problem. Informally, in a census individual respondents give private information to a trusted party (the census bureau), who publishes a sanitized version of the data. There are two fundamentally conflicting requirements: privacy for the respon ..."
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Cited by 89 (12 self)
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Abstract. We initiate a theoretical study of the census problem. Informally, in a census individual respondents give private information to a trusted party (the census bureau), who publishes a sanitized version of the data. There are two fundamentally conflicting requirements: privacy for the respondents and utility of the sanitized data. Unlike in the study of secure function evaluation, in which privacy is preserved to the extent possible given a specific functionality goal, in the census problem privacy is paramount; intuitively, things that cannot be learned “safely ” should not be learned at all. An important contribution of this work is a definition of privacy (and privacy compromise) for statistical databases, together with a method for describing and comparing the privacy offered by specific sanitization techniques. We obtain several privacy results using two different sanitization techniques, and then show how to combine them via cross training. We also obtain two utility results involving clustering. 1
Parallel Algorithms for Hierarchical Clustering
 Parallel Computing
, 1995
"... Hierarchical clustering is a common method used to determine clusters of similar data points in multidimensional spaces. O(n 2 ) algorithms are known for this problem [3, 4, 10, 18]. This paper reviews important results for sequential algorithms and describes previous work on parallel algorithms f ..."
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Cited by 80 (1 self)
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Hierarchical clustering is a common method used to determine clusters of similar data points in multidimensional spaces. O(n 2 ) algorithms are known for this problem [3, 4, 10, 18]. This paper reviews important results for sequential algorithms and describes previous work on parallel algorithms for hierarchical clustering. Parallel algorithms to perform hierarchical clustering using several distance metrics are then described. Optimal PRAM algorithms using n log n processors are given for the average link, complete link, centroid, median, and minimum variance metrics. Optimal butterfly and tree algorithms using n log n processors are given for the centroid, median, and minimum variance metrics. Optimal asymptotic speedups are achieved for the best practical algorithm to perform clustering using the single link metric on a n log n processor PRAM, butterfly, or tree. Keywords. Hierarchical clustering, pattern analysis, parallel algorithm, butterfly network, PRAM algorithm. 1 In...
MAFIA: Efficient and Scalable Subspace Clustering for Very Large Data Sets
, 1999
"... Clustering techniques are used in database mining for finding interesting patterns in high dimensional data. These are useful in various applications of knowledge discovery in databases. Some challenges in clustering for large data sets in terms of scalability, data distribution, understanding en ..."
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Cited by 64 (0 self)
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Clustering techniques are used in database mining for finding interesting patterns in high dimensional data. These are useful in various applications of knowledge discovery in databases. Some challenges in clustering for large data sets in terms of scalability, data distribution, understanding endresults, and sensitivity to input order, have received attention in the recent past. Recent approaches attempt to find clusters embedded in subspaces of high dimensional data. In this paper we propose the use of adaptive grids for efficient and scalable computation of clusters in subspaces for large data sets and large number of dimensions. The bottomup algorithm for subspace clustering computes the dense units in all dimensions and combines these to generate the dense units in higher dimensions. Computation is heavily dependent on the choice of the partitioning parameter chosen to partition each dimension into intervals (bins) to be tested for density. The number of bins determine...
On the merits of building categorization systems by supervised clustering
 Proceedings of KDD99, 5th ACM International Conference on Knowledge Discovery and Data Mining
, 1999
"... This paper investigates the use of supervised clustering in order to create sets of categories for classification of documents. We use information from a preexisting taxonomy in order to supervise the creation of a set of related clusters, though with some freedom in defining and creating the class ..."
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Cited by 46 (1 self)
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This paper investigates the use of supervised clustering in order to create sets of categories for classification of documents. We use information from a preexisting taxonomy in order to supervise the creation of a set of related clusters, though with some freedom in defining and creating the classes. We show that the advantage of using supervised clustering is that it is possible to have some control over the range of subjects that one would like the categorization system to address, but with a precise mathematical definition of each category. We then categorize documents using this a priori knowledge of the definition of each category. We also discuss a new technique to help the classifier distinguish better among closely related clusters. Finally, we show empirically that this categorization system utilizing a machinederived taxonomy performs as well as a manual categorization process, but at a far lower cost. 1
Collective, Hierarchical Clustering from Distributed, Heterogeneous Data
, 1999
"... . This paper presents the Collective Hierarchical Clustering (CHC) algorithm for analyzing distributed, heterogeneous data. This algorithm first generates local cluster models and then combines them to generate the global cluster model of the data. The proposed algorithm runs in O(jSjn 2 ) tim ..."
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Cited by 44 (8 self)
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. This paper presents the Collective Hierarchical Clustering (CHC) algorithm for analyzing distributed, heterogeneous data. This algorithm first generates local cluster models and then combines them to generate the global cluster model of the data. The proposed algorithm runs in O(jSjn 2 ) time, with a O(jSjn) space requirement and O(n) communication requirement, where n is the number of elements in the data set and jSj is the number of data sites. This approach shows significant improvement over naive methods with O(n 2 ) communication costs in the case that the entire distance matrix is transmitted and O(nm) communication costs to centralize the data, where m is the total number of features. A specific implementation based on the single link clustering and results comparing its performance with that of a centralized clustering algorithm are presented. An analysis of the algorithm complexity, in terms of overall computation time and communication requirements, is pres...
Efficient Video Similarity Measurement with Video Signature
 IEEE Transactions on Circuits and Systems for Video Technology
, 2003
"... The proliferation of video content on the web makes similarity detection an indispensable tool in web data management, searching, and navigation. In this paper, we propose a number of algorithms to efficiently measure video similarity. We define video as a set of frames, which are represented as hig ..."
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Cited by 40 (5 self)
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The proliferation of video content on the web makes similarity detection an indispensable tool in web data management, searching, and navigation. In this paper, we propose a number of algorithms to efficiently measure video similarity. We define video as a set of frames, which are represented as high dimensional vectors in a feature space. Our goal is to measure Ideal Video Similarity (IVS), defined as the percentage of clusters of similar frames shared between two video sequences. Since IVS is too complex to be deployed in large database applications, we approximate it with Voronoi Video Similarity (VVS), defined as the volume of the intersection between Voronoi Cells of similar clusters. We propose a class of randomized algorithms to estimate VVS by first summarizing each video with a small set of its sampled frames, called the Video Signature (ViSig), and then calculating the distances between corresponding frames from the two ViSig's. By generating samples with a probability distribution that describes the video statistics, and ranking them based upon their likelihood of making an error in the estimation, we show analytically that ViSig can provide an unbiased estimate of IVS. Experimental results on a large dataset of web video and a set of MPEG7 test sequences with artificially generated similar versions are provided to demonstrate the retrieval performance of our proposed techniques.