Updating Technique for Frequent Itemsets in Distributed Database System in the Case Minimal Support Change

Some algorithms have been proposed for maintaining the association rules mined in database, but very little research has been done in updating techniques for association rules in distributed databases. Updating technique for frequent itemsets is a key problem of updating association rules in distributed database system. Updating technique for frequent itemsets in distributed databases is studied in this paper. The more general incremental updating algorithms ULFS and UGFS are presented for maintaining the frequent itemsets discovered in a distributed database system in the case minimal support change. The algorithm ULFS is designed for updating local frequent itemsets discovered in a site. The algorithm UGFS is designed for computing global frequent itemsets when the minimal support change in a distributed database. The algorithms have been implemented using Java and its performance is studied. The experiment results show that the algorithms are valid and fast. UGFS has superior performance when comparing with the direct application of DMA to mine global frequent itemsets.