@inproceedings{barber1998ensemble, author = {Barber, D. and Bishop, Christopher}, title = {Ensemble learning in Bayesian neural networks}, booktitle = {Generalization in Neural Networks and Machine Learning}, year = {1998}, month = {January}, abstract = {Bayesian treatments of learning in neural networks are typically based either on a local Gaussian approximation to a mode of the posterior weight distribution, or on Markov chain Monte Carlo simulations. A third approach, called `ensemble learning', was introduced by Hinton (1993). It aims to approximate the posterior distribution by minimizing the Kullback-Leibler divergence between the true posterior and a parametric approximating distribution. The original derivation of a deterministic algorithm relied on the use of a Gaussian approximating distribution with a diagonal covariance matrix and hence was unable to capture the posterior correlations between parameters. In this chapter we show how the ensemble learning approach can be extended to full-covariance Gaussian distributions while remaining computationally tractable. We also extend the framework to deal with hyperparameters, leading to a simple re-estimation procedure. One of the benefits of our approach is that it yields a strict lower bound on the marginal likelihood, in contrast to other approximate procedures.}, publisher = {Springer Verlag}, url = {http://approjects.co.za/?big=en-us/research/publication/ensemble-learning-in-bayesian-neural-networks/}, pages = {215-237}, edition = {Generalization in Neural Networks and Machine Learning}, }