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PartitionBased Clustering in Object Bases: From Theory to Practice
, 1993
"... We classify clustering algorithms into sequencebased techniqueswhich transform the object net into a linear sequenceand partitionbased clustering algorithms. Tsangaris and Naughton [TN91, TN92] have shown that the partitionbased techniques are superior. However, their work is based on a sin ..."
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Cited by 22 (7 self)
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We classify clustering algorithms into sequencebased techniqueswhich transform the object net into a linear sequenceand partitionbased clustering algorithms. Tsangaris and Naughton [TN91, TN92] have shown that the partitionbased techniques are superior. However, their work is based on a single partitioning algorithm, the Kernighan and Lin heuristics, which is not applicable to realistically large object bases because of its high runningtime complexity. The contribution of this paper is twofold: (1) we devise a new class of greedy object graph partitioning algorithms (GGP) whose runningtime complexity is moderate while still yielding good quality results. For large object graphs GGP is the best known heuristics with an acceptable runningtime. (2) We carry out an extensive quantitative analysis of all wellknown partitioning algorithms for clustering object graphs. Our analysis yields that no one algorithm performs superior for all object net characteristics. Therefore, we d...
Clustering in Object Bases
, 1992
"... We investigate clustering techniques that are specifically tailored for objectoriented database systems. Unlike traditional database systems objectoriented data models incorporate the application behavior in the form of typeassociated operations. This source of information is exploited for clu ..."
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Cited by 7 (3 self)
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We investigate clustering techniques that are specifically tailored for objectoriented database systems. Unlike traditional database systems objectoriented data models incorporate the application behavior in the form of typeassociated operations. This source of information is exploited for clustering decisions by statically determining the operations' access behavior applying dataflow analysis techniques. This process yields a set of weighted access paths. The statically extracted (syntactical) access patterns are then matched with the actual object net. Thereby the interobject reference chains that are likely being traversed in the database applications accumulate correspondingly high weights. The object net can then be viewed as a weighted graph whose nodes correspond to objects and whose edges are weighted interobject references. We then employ a newly developed (greedy) heuristics for graph partitioningwhich exhibits moderate complexity and, thus, is applicable t...
Circuit Bases of Strongly Connected Digraphs
, 2001
"... The cycle space of a strongly connected graph has a basis consisting of directed circuits. The concept of relevant circuits is introduced as a generalization of the relevant cycles in undirected graphs. A polynomial time algorithm for the computation of a minimum weight directed circuit basis is ..."
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Cited by 7 (0 self)
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The cycle space of a strongly connected graph has a basis consisting of directed circuits. The concept of relevant circuits is introduced as a generalization of the relevant cycles in undirected graphs. A polynomial time algorithm for the computation of a minimum weight directed circuit basis is outlined.