About the Locality of Kernels in

Gaussian kernels are widely used in many data analysis tools such as Radial-Basis Function networks, Support Vector Machines and many others. Gaussian kernels are most often deemed to provide a local measure of similarity between vectors. In this paper, we show that Gaussian kernels are adequate measures of similarity when the representation dimension of the space remains small, but that they fail to reach their goal in high-dimensional spaces. We suggest the use of p- Gaussian kernels that include a supplementary degree of freedom in order to adapt to the distribution of data in high-dimensional problems. The use of such more flexible kernel may greatly improve the numerical stability of algorithms, and also the discriminative power of distance- and neighbor-based data analysis methods