I. Introduction
Sequential pattern mining (SPM) has been an important topic of data mining research, and has a wide range of applications, e.g., analysis of DNA sequence patterns, customer purchase behavior analysis, network access mode of analysis, the analysis of scientific experiments, disease treatment early diagnosis, and prediction of natural disasters and so on. The task of sequential pattern mining is to identify all sequence database support which is not less than the minimum support threshold of frequent sequences (sequence mode), It is firstly proposed by Agrawal R. et al. in the shopping basket data analysis [10]. In the past decades, many algorithms on SPM have been proposed. For example Srikant et al. proposed the GSP method in [11], Zaki proposed the SPADE method in [12]. In addition, Constraint-based sequential pattern mining algorithm, based on the pattern of growth sequential pattern mining methods, and databases based on the projection of the sequential pattern mining methods have been proposed. And moreover, there are some expansions of research on SPM, such as closed sequential pattern mining, parallel mining, distributed mining, multi-dimensional sequential pattern mining and approximate sequential pattern mining.