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Constrained Bayesian Inference for Low Rank Multitask Learning
Proceedings of the 29th Conference on Uncertainty in Artificial Intelligence, PMLR R11:135-144, 2013.
Abstract
We present a novel approach for constrained Bayesian inference. Unlike current methods, our approach does not require convexity of the con- straint set. We reduce the constrained variational inference to a parametric optimization over the feasible set of densities and propose a general recipe for such problems. We apply the proposed constrained Bayesian inference approach to mul- titask learning subject to rank constraints on the weight matrix. Further, constrained parameter estimation is applied to recover the sparse con- ditional independence structure encoded by prior precision matrices. Our approach is motivated by reverse inference for high dimensional func- tional neuroimaging, a domain where the high dimensionality and small number of examples re- quires the use of constraints to ensure meaning- ful and effective models. For this application, we propose a model that jointly learns a weight ma- trix and the prior inverse covariance structure be- tween different tasks. We present experimental validation showing that the proposed approach outperforms strong baseline models in terms of predictive performance and structure recovery.