分布式数据库关联规则更新算法

提出了一种分布式关联规则增量更新算法（IUAAR），它可对数据库发生变化的情况进行归类．该算法主要采用改进了的FP树结构，通过传送被约束子树来挖掘全局频繁项目集，并充分利用快速分布式挖掘算法建立的各局部FP树，只对新增加了的全局频繁项目修改相应的改进FP树，挖掘其对应的被约束子树，同时利用已挖掘的全局频繁项目集对原全局频繁项目对应的被约束子树进行有效修剪．实验结果表明，该算法的运算速度比快速分布式挖掘算法提高了1倍，在最坏的情况下，对各局部数据库也仅需要扫描一遍，从而可提高数据库的维护效率．

Updating Mining Algorithm for Distributed Association Rules

A new algorithm IUAAR(incremental updating algorithm for association rules) is introduced,by which the change of database records can be classified.The improved FP-tree structure is adopted and the global frequent itemsets are mined by transmitting constrained sub-tree.Utilizing the local FP-tree created by FDMA(fast distributed mining algorithm) only the FP-tree of the added global frequent items is modified.Moreover,using the mined results,the constrained sub-trees of the incremental global frequent itemsets that are transmitted in network are mined.The constrained sub-trees of the original global frequent itemsets can be pruned without transmitting them.Experiments show that in the worst case,IUAAR only scans every local transaction database once,thus the communication cost is dramatically decreased and the maintenance efficiency of global frequent itemsets is improved,and the mining speed of IUAAR algorithm is increased by at least two times in comparison with FDMA.