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CMU-CS-04-101
Computer Science Department
School of Computer Science, Carnegie Mellon University
CMU-CS-04-101
Diffusion Kernels on Statistical Manifolds
John Lafferty, Guy Lebanon
January 2004
CMU-CS-04-101.ps
CMU-CS-04-101.pdf
Keywords: Kernels, heat equation, diffusion, information
geometry, text classification
A family of kernels for statistical learning is introduced
that exploits the geometric structure of statistical models.
The kernels are based on the heat equation on the Riemannian
manifold defined by the Fisher information metric associated with
a statistical family, and generalize the Gaussian kernel of
Euclidean space. As an important special case, kernels based on
the geometry of multinomial families are derived, leading to
kernel-based learning algorithms that apply naturally to
discrete data. Bounds on covering numbers and Rademacher averages
for the kernels are proved using bounds on the eigenvalues of the
Laplacian on Riemannian manifolds. Experimental results are
presented for document classification, for which the use of
multinomial geometry is natural and well motivated, and
improvements are obtained over the standard use of Gaussian or
linear kernels, which have been the standard for text classification.
39 pages
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