一种改进的频繁无规则集集合开采算法

数据挖掘的一个基本任务是在海量数据的数据库中开采频繁项目集。本文提出了一种方法，不用开采频繁项目集全集，而是开采它的一个称为频繁无规则集集合的精简集。我们能用频繁无规则集集合还原出完整的频繁项目集集合和它们的精确支持度而不用读取数据库。可以看到，对频繁无规则集集合的开采是高效的。我们给出了一个算法HOPE-Ⅲ来开采频繁无规则集集合，并将它和算法A-Close进行了比较。实验结果显示，HOPE-Ⅲ在任何情况下都比A-Close的性能更好。

An Optimized Algorithm for Mining Frequent Rule-Free Sets

Given a large collection of transactions containing items, a basic common problem is to extract the so-called frequent itemset. The idea presented in this paper is to extract a condensed representation of the frequent itemsets called rule-free sets, instead of extracting the whole frequent itemset collection. We show that this condensed representation can be used to regenerate all frequent patterns and their exact frequencies without any access to the original data. An algorithm named HOPE-III is given to extract the frequent rule-free sets. We compared it with an algorithm named A-Close which extracts another condensed representation of frequent itemsets previously investigated in the literature called frequent closed sets. The experiments show that in all cases, HOPE-III is much more efficient than A-Close.