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arXiv 0803.3224cs.DB
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基于模型的频繁约束挖掘事务数据关联

A Model-Based Frequency Constraint for Mining Associations from Transaction Data

Michael Hahsler

摘要:

频繁项集挖掘是一种在数据库中发现关联项的常用方法。对于这种方法,支持度,形成关联的项目的共现频率,被用作关联的重要性的主要指标。使用单个用户指定的支持阈值来决定是否应进一步调查关联。支持有一些已知的问题,罕见的项目,有利于较短的项目集,有时产生误导性的协会。在本文中,我们开发了一种新的基于模型的频率约束作为一个单一的,用户指定的最小支持的替代。该约束通过应用简单的随机混合模型(NB模型)来利用生成事务数据的过程的知识,该模型允许事务数据的通常高度偏斜的项目频率分布。用户指定的精度阈值与模型一起使用,以找到项目集组的局部频率阈值。在此基础上,提出了NB-频繁项集的概念,并提出了一种挖掘算法来发现数据库中所有的NB-频繁项集。在公开的交易数据库的实验中,我们表明,新的约束提供了一个单一的最小支持阈值的改进和精度阈值是更强大的,更容易设置和解释的用户。

英文摘要:

Mining frequent itemsets is a popular method for finding associated items in databases. For this method, support, the co-occurrence frequency of the items which form an association, is used as the primary indicator of the associations's significance. A single user-specified support threshold is used to decided if associations should be further investigated. Support has some known problems with rare items, favors shorter itemsets and sometimes produces misleading associations. In this paper we develop a novel model-based frequency constraint as an alternative to a single, user-specified minimum support. The constraint utilizes knowledge of the process generating transaction data by applying a simple stochastic mixture model (the NB model) which allows for transaction data's typically highly skewed item frequency distribution. A user-specified precision threshold is used together with the model to find local frequency thresholds for groups of itemsets. Based on the constraint we develop the notion of NB-frequent itemsets and adapt a mining algorithm to find all NB-frequent itemsets in a database. In experiments with publicly available transaction databases we show that the new constraint provides improvements over a single minimum support threshold and that the precision threshold is more robust and easier to set and interpret by the user.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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