A new unsupervised competitive learning rule is introduced, called the Self-organizing free-topology map (Softmap) algorithm, for nonparametric density estimation. The receptive fields of the formal neurons are overlapping, radially-symmetric kernels, the radii of which are adapted to the local input density together with the weight vectors which define the kernel centers. A fuzzy code membership function is introduced in order to encompass, in a novel way, the presence of overlapping receptive… CONTINUE READING
Table I. Density function estimation using four different methods (rows): the variable kernel method (VK), Kohonen’s SOM algorithm, VBAR and Softmap. The term between brackets [.] indicates the lattice size. See text for explanation.