|   | 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.psCMU-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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