Mining frequent intra-sequence and inter-sequence patterns using bitmap with a maximal span

Frequent intra-sequence pattern mining and inter-sequence pattern mining are both important ways of association rule mining for different applications. However, most algorithms focus on just one of them, as attempting both is usually inefficient. To address this deficiency, FIIP-BM, a Frequent Intra-sequence and Inter-sequence Pattern mining algorithm using Bitmap with a maxSpan is proposed. FIIP-BM transforms each transaction to a bit vector, adjusts the maximal span according to user's demand and obtains the frequent sequences by logic And-operation. For candidate 2-pattern generation, the subscripts of the joining items should be checked first; the bit vector of the joining item will be left-shifted before calculation if the subscript is not 0. Left alignment rule is used for different bit vector length problems. FIIP-BM can mine both intra-sequence and inter-sequence patterns. Experiments are conducted to demonstrate the computational speed and memory efficiency of the FIIP-BM algorithm.