Abstract
A mechanism is presented for classifying phonocardiograms (PCGs) by interpreting PCGs as time series and using the concept of motifs, times series subsequences that are good discriminators of class, to support nearest neighbour classification. A particular challenge addressed by the work is that PCG time series are large which renders exact motif discovery to be computationally expensive; it is not realistic to compare every candidate time series subsequence with every other time series subsequence in order to discover exact motifs. Instead, a mechanism is proposed the firstly makes use of the cyclic nature of PCGs and secondly adopts a novel time series pruning mechanism. The evaluation, conducted using a canine PCG dataset, illustrated that the proposed approach produced the same classification accuracy but in a significantly more efficient manner.