The build of a dynamic classifier selection ICBP system and its application to pattern recognition

In neural network ensemble, the diversity of its constitutive component networks is a crucial factor to boost its generalization performance. In terms of how each ensemble system solves the problem, we can roughly categorize the existing ensemble mechanism into two groups: data-driven and model-driven ensembles. The former engenders diversity to ensemble members by manipulating the data, while the latter realizes ensemble diversity by manipulating the component models themselves. Within a neural network ensemble, standard back-propagation (BP) networks are usually used as a base component. However, in this article, we will use our previously designed improved circular back-propagation (ICBP) neural network to establish such an ensemble. ICBP differentiates from BP network not only because an extra anisotropic input node is added, but also more importantly, because of the introduction of the extra node, it possesses an interesting property apart from the BP network, i.e., just through directly assigning different sets of values 1 and −1 to the weights connecting the extra node to all the hidden nodes, we can construct a set of heterogeneous ICBP networks with different hidden layer activation functions, among which we select four typical heterogeneous ICBPs to build a dynamic classifier selection ICBP system (DCS-ICBP). The system falls into the category of model-driven ensemble. The aim of this article is to explore the relationship between the explicitly constructed ensemble and the diversity scale, and further to verify feasibility and effectiveness of the system on classification problems through empirical study. Experimental results on seven benchmark classification tasks show that our DCS-ICBP outperforms each individual ICBP classifier and surpasses the performance of combination of ICBP using the majority voting technique, i.e. majority voting ICBP system (MVICBP). The successful simulation results validate that in DCS-ICBP we provide a new constructive method for diversity enforcement for ICBP ensemble systems.