eprintid: 399130 rev_number: 107 eprint_status: archive userid: 608 dir: disk0/00/39/91/30 datestamp: 2010-12-13 22:05:01 lastmod: 2021-09-28 22:26:22 status_changed: 2015-11-25 16:03:48 type: article metadata_visibility: show item_issues_count: 0 creators_name: Sun, S creators_name: Shawe-Taylor, J title: Sparse Semi-supervised Learning Using Conjugate Functions ispublished: pub divisions: UCL divisions: B04 divisions: C05 divisions: F48 keywords: semi-supervised learning, Fenchel-Legendre conjugate, representer theorem, multiview regularization, support vector machine, statistical learning theory note: Copyright © 2010 Shiliang Sun and John Shawe-Taylor. abstract: In this paper, we propose a general framework for sparse semi-supervised learning, which concerns using a small portion of unlabeled data and a few labeled data to represent target functions and thus has the merit of accelerating function evaluations when predicting the output of a new example. This framework makes use of Fenchel-Legendre conjugates to rewrite a convex insensitive loss involving a regularization with unlabeled data, and is applicable to a family of semi-supervised learning methods such as multi-view co-regularized least squares and single-view Laplacian support vector machines (SVMs). As an instantiation of this framework, we propose sparse multi-view SVMs which use a squared ε-insensitive loss. The resultant optimization is an inf-sup problem and the optimal solutions have arguably saddle-point properties. We present a globally optimal iterative algorithm to optimize the problem. We give the margin bound on the generalization error of the sparse multi-view SVMs, and derive the empirical Rademacher complexity for the induced function class. Experiments on artificial and real-world data show their effectiveness. We further give a sequential training approach to show their possibility and potential for uses in large-scale problems and provide encouraging experimental results indicating the efficacy of the margin bound and empirical Rademacher complexity on characterizing the roles of unlabeled data for semi-supervised learning date: 2010-09 official_url: http://www.jmlr.org/papers/v11/sun10a.html vfaculties: VENG oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_source: WoS-Lite elements_id: 280280 lyricists_name: Shawe-Taylor, John lyricists_id: JSHAW87 full_text_status: public publication: Journal of Machine Learning Research volume: 11 pagerange: 2423 - 2455 issn: 1532-4435 citation: Sun, S; Shawe-Taylor, J; (2010) Sparse Semi-supervised Learning Using Conjugate Functions. Journal of Machine Learning Research , 11 2423 - 2455. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/399130/1/Shawe-Taylor_sun10a%255B1%255D.pdf