# Is it still an open question to select the parameter of Gaussian kernel SVMs?

I am learning Gaussian kernel SVMs recently. I have to choose the parameter $\epsilon$ for Gaussian kernel, $$k(x,t)=e^{-\frac{\|x-y\|_2^2}{2\epsilon}}.$$

I try to find the answer in literature. I found some to analyze the parameters like 'A User's Guide to Support Vector Machines' (PDF). I really want to analyze these by myself step by step. But I have work to finish, you know. I found a paper 'Practical Selection of SVM Parameters and Noise Estimation for SVM Regression' (PDF).