2008 ConvexMultiTaskFeatureLearning

Subject Headings: Transfer Learning Algorithm; Feature Learning; Learning Sparse Representations.

Notes

We present a method for learning sparse representations shared across multiple tasks. This method is a generalization of the well-known single-task 1-norm regularization. It is based on a novel non-convex regularizer which controls the number of learned features common across the tasks. We prove that the method is equivalent to solving a convex optimization problem for which there is an iterative algorithm which converges to an optimal solution. The algorithm has a simple interpretation: it alternately performs a supervised and an unsupervised step, where in the former step it learns task-specific functions and in the latter step it learns common-across-tasks sparse representations for these functions. We also provide an extension of the algorithm which learns sparse nonlinear representations using kernels. We report experiments on simulated and real data sets which demonstrate that the proposed method can both improve the performance relative to learning each task independently and lead to a few learned features common across related tasks. Our algorithm can also be used, as a special case, to simply select -- not learn -- a few common variables across the tasks.

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	Author	volume	Date Value	title	type	journal	titleUrl	doi	note	year
2008 ConvexMultiTaskFeatureLearning	Massimiliano Pontil Andreas Argyriou Theodoros Evgeniou			Convex Multi-task Feature Learning				10.1007/s10994-007-5040-8		2008