Comparing "pattern discovery" and back-propagation classifiers

The pattern discovery (PD) algorithm of Wang and Wong was applied as a classifier to several continuous-valued data sets generated to explore performance across a selection of interesting linearly and non-linearly separable class distributions. Performance of several configurations of PD and backpropagation (BP) neural network classifiers and a minimum inter-class distance (MICD) classifier was quantified and compared. The best performance of the PD and BP classifiers were found to be similar for all class distributions studied and close to the optimal IMICD performance for linearly separable class distributions. The performance of both PD and BP classifiers was dependent on the classifier configuration. PD classifier performance depended on the number of intervals used to quantize the continuous data in a predictable, class-distribution independent way. BP performance depended on the number of hidden nodes in a way which was class-distribution dependent and difficult to determine a priori. The transparency and statistical validity of the patterns used and the decisions made by PD classifiers make them highly suitable for problems in which the rationale and confidence of classifications are required so that multiple classifications can be effectively combined to support decisions in a broader context such as medical diagnosis. The strong absolute and relative performance of PD classifiers and the relative simplicity of their implementation when applied to continuous-valued data suggest that they can be effectively utilized in decision support systems in which the underlying data is continuous or discrete valued.