L-MAX Frequent Itemsets and Algorithm of Mining L-MAX Frequent Itemsets
Presented a problem of mining maximal frequent itemsets with constrained itemsets-length and generating corresponding transaction information of itemsets,which is defined as L-MAX frequent itemsets mining.The constraint characteristic of itemsets-length and the strategy of transaction sets storaged and generated is emphatically studied in this paper.Firstly the properties of L-MAX frequent itemsets is analysed.Then by extending FP-tree structure an ExFP-tree data structure is presented and the algorithm of ExFP-tree generated is given.According to the character of prefixing paths shared in FP-tree,ExFP-tree implements compressingly storage of transaction information with sharing the transaction information of descendant nodes.Finally based on FP-MAX algorithm,an algorithm of mining L-MAX frequent itemsets based on ExFP-tree is presented.The main idea is firstly using look-ahead pruning method process ExFP-tree according to the properties of L-MAX frequent itemsets and then mining maximal frequent itemsets.To generate the corresponding transaction sets backdating and direct locating strategy is used.