关键词: 定位子集, 自顶向下, 长频繁项目集, 挖掘算法

Abstract: Aiming at disadvantage of presented top-down mining algorithm that has redundant computing when non-frequent itemsets generate their subsets and prune some repeatedly generated subsets，an algorithm of top-down mining based on orientation subset is proposed，which is suitable for mining relative long frequent itemsets.The algorithm uses orientation subset to generate subsets of non-frequent itemsets by top-down strategy，which can efficiently prune redundant subsets and reduce repeatedly computing to improve its efficiency.Comparing with presented top-down mining algorithms，the experiments indicate that it is fast and efficient.

Key words: orientation subset, top-down, long frequent itemsets, mining algorithm