改进的 PrefixSpan 算法及其在序列模式挖掘中的应用

摘要

由于序列模式挖掘需要花费大量计算时间，并需要占用大量存储空间。减少计算量、节省存储空间开销成为序列模式挖掘的关键。因PrefixSpan 算法不产生候选，而适当应用Bitmap数据结构可避免重复扫描数据库，基于此，本文提出了BM-PrefixSpan算法，用于序列模式挖掘，设计并构造了PFPBM（ Prefix of First Position on BitMap ）表用于记录序列中的每个项在位图中第1次出现的位置。实验结果表明， BM-PrefixSpan 算法综合了PrefixSpan 和SPAM算法的优点，能够更快、更好地挖掘出序列模式。%Because sequential pattern mining needs a lot of computing time and storage space , how to re-duce the amount of calculation and storage space becomes the key of the sequential pattern mining algo -rithm.Combining the PrefixSpan algorithm with Bitmap data structure , this text proposes an improved se-quential pattern mining algorithm BM-PrefixSpan .The PFPBM ( Prefix of First Position on BitMap ) table was designed and implemented .When a new item appeared in a sequence , it was recorded in the PFPBM table.The experimental results show that the BM-prefixspan algorithm mines sequential patterns faster and better than others .