Learning in reproducing kernel Kreın spaces
We formulate a novel regularized risk minimization problem for learning in reproducing kernel Kreın spaces and show that the strong representer theorem applies to it. As a result of the latter, the learning problem can be expressed as the minimization of a quadratic form over a hypersphere of consta...
| Main Authors: | , |
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| Format: | Conference or Workshop Item |
| Published: |
2018
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| Online Access: | https://eprints.nottingham.ac.uk/52412/ |
| _version_ | 1848798720400818176 |
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| author | Oglic, Dino Gärtner, Thomas |
| author_facet | Oglic, Dino Gärtner, Thomas |
| author_sort | Oglic, Dino |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | We formulate a novel regularized risk minimization problem for learning in reproducing kernel Kreın spaces and show that the strong representer theorem applies to it. As a result of the latter, the learning problem can be expressed as the minimization of a quadratic form over a hypersphere of constant radius. We present an algorithm that can find a globally optimal solution to this nonconvex optimization problem in time cubic in the number of instances. Moreover, we derive the gradient of the solution with respect to its hyperparameters and, in this way, provide means for efficient hyperparameter tuning. The approach comes with a generalization bound expressed in terms of the Rademacher complexity of the corresponding hypothesis space. The major advantage over standard kernel methods is the ability to learn with various domain specific similarity measures for which positive definiteness does not hold or is difficult to establish. The approach is evaluated empirically using indefinite kernels defined on structured as well as vectorial data. The empirical results demonstrate a superior performance of our approach over the state-of-the-art baselines. |
| first_indexed | 2025-11-14T20:24:15Z |
| format | Conference or Workshop Item |
| id | nottingham-52412 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T20:24:15Z |
| publishDate | 2018 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-524122020-05-04T19:45:54Z https://eprints.nottingham.ac.uk/52412/ Learning in reproducing kernel Kreın spaces Oglic, Dino Gärtner, Thomas We formulate a novel regularized risk minimization problem for learning in reproducing kernel Kreın spaces and show that the strong representer theorem applies to it. As a result of the latter, the learning problem can be expressed as the minimization of a quadratic form over a hypersphere of constant radius. We present an algorithm that can find a globally optimal solution to this nonconvex optimization problem in time cubic in the number of instances. Moreover, we derive the gradient of the solution with respect to its hyperparameters and, in this way, provide means for efficient hyperparameter tuning. The approach comes with a generalization bound expressed in terms of the Rademacher complexity of the corresponding hypothesis space. The major advantage over standard kernel methods is the ability to learn with various domain specific similarity measures for which positive definiteness does not hold or is difficult to establish. The approach is evaluated empirically using indefinite kernels defined on structured as well as vectorial data. The empirical results demonstrate a superior performance of our approach over the state-of-the-art baselines. 2018-07-10 Conference or Workshop Item PeerReviewed Oglic, Dino and Gärtner, Thomas (2018) Learning in reproducing kernel Kreın spaces. In: 35th International Conference on Machine Learning, 10-15 July, 2018, Stockholm, Sweden. |
| spellingShingle | Oglic, Dino Gärtner, Thomas Learning in reproducing kernel Kreın spaces |
| title | Learning in reproducing kernel Kreın spaces |
| title_full | Learning in reproducing kernel Kreın spaces |
| title_fullStr | Learning in reproducing kernel Kreın spaces |
| title_full_unstemmed | Learning in reproducing kernel Kreın spaces |
| title_short | Learning in reproducing kernel Kreın spaces |
| title_sort | learning in reproducing kernel kreın spaces |
| url | https://eprints.nottingham.ac.uk/52412/ |