Frequent changing pattern extraction device

摘要

A frequent changing pattern extraction device which extracts a frequent changing pattern from an ever-changing network structure includes: a conversion unit which converts each of a plurality of graph sequences into an operator sequence by expressing changes, from a first graph included in the graph sequence to a second graph which is temporally adjacent to the first graph, using operators indicating operations necessary to transform the first graph into the second graph, each graph sequence including a plurality of graphs that show temporal changes in the graphs and each of the graphs including a vertex corresponding to a data piece and an edge corresponding to a link between data pieces; and an extraction unit which extracts an operator subsequence that appears at least a predetermined number of times in the plurality of operator sequences corresponding to the plurality of graph sequences, based on the anti-monotonicity used in the Apriori algorithm.