Mining Order-Preserving Submatrices from Data with Repeated Measurements

Order-preserving submatrices (OPSM´s) have been shown useful in capturing concurrent patterns in data when the relative magnitudes of data items are more important than their absolute values. To cope with data noise, repeated experiments are often conducted to collect multiple measurements. We propose and study a more robust version of OPSM, where each data item is represented by a set of values obtained from replicated experiments. We call the new problem OPSM-RM (OPSM with repeated measurements). We define OPSM-RM based on a number of practical requirements. We discuss the computational challenges of OPSM-RM and propose a generic mining algorithm. We further propose a series of techniques to speed up two time-dominating components of the algorithm. We clearly show the effectiveness of our methods through a series of experiments conducted on real microarray data.