Adaptive internal representation in circular back-propagation networks

Abstract

Surface- and prototype-based models are often regarded as alternative paradigms to represent internal knowledge in trained neural networks. This paper analyses a network model (Circular Back-Propagation) that overcomes such dualism by choosing the best-fitting representation adaptively. The model involves a straightforward modification to classical feed-forward structures to let neurons implement hyperspherical boundaries; as a result, it exhibits a notable representation power, and benefits from the simplicity and effectiveness of classical back-propagation training. Artificial testbeds support the model definition by demonstrating its basic properties; an application to a real, complex problem in the clinical field shows the practical advantages of the approach.