Deterministically annealed mixture of experts models for statistical regression
A new and effective design method is presented for statistical regression functions that belong to the class of mixture models. The class includes the hierarchical mixture of experts (HME) and the normalized radial basis functions (NRBF). Design algorithms based on the maximum likelihood (ML) approach, which emphasize a probabilistic description of the model, have attracted much interest in HME and NRBF models. However, their design objective is mismatched to the original squared-error regression cost and the algorithms are easily trapped by poor local minima on the cost surface. In this paper, we propose an extension of the deterministic annealing (DA) method for the design of mixture-based regression models. We construct a probabilistic framework, but unlike the ML method, we directly optimize the squared-error regression cost, while avoiding poor local minima. Experimental results show that the DA method outperforms standard design methods for both HME and NRBF regression models.