Kernel CMAC with reduced memory complexity

Abstract

Cerebellar Model Articulation Controller (CMAC) has some attractive features: fast learning capability and the possibility of efficient digital hardware implementation. Besides these attractive features it has a serious drawback: its memory complexity may be very large. In multidimensional case this may be so large that practically it cannot be implemented. To reduce memory complexity several different approaches were suggested so far. Although these approaches may greatly reduce memory complexity we have to pay a price for this complexity reduction. Either both modelling and generalization capabilities are deteriorated, or the training process will be much more complicated. This paper proposes a new approach of complexity reduction, where properly constructed hash-coding is combined with regularized kernel representation. The proposed version exploits the benefits of kernel representation and the complexity reduction effect of hash-coding, while smoothing regularization helps to reduce the performance degradation. © 2009 Springer Berlin Heidelberg.