Unusual pattern detection based on hyper surface and minimum spanning tree

More analysis has been done to discover the meaningful unusual patterns which may mean fraud or anomaly. In this paper, a novel unsupervised approach for discovering meaningful unusual observations is proposed. We firstly apply an unsupervised version of Hyper Surface Classification (HSC) algorithm to gain the separating hyper surface. It needs no domain knowledge but can not discover the local unusual pattern. To solve this problem, we additionally search the Minimum Spanning Tree (MST). Given the domain knowledge, a process of subdividing is proposed to detect unusual pattern in each Minimum Spanning Tree. Experimental results show that our approach can detect unusual patterns effectively, even some of which are overlooked by using the traditional clustering and outlier detection algorithms.