In contrast, methods using radial-basis function (RBF) kernels do not provide weight vectors, via which we cannot obtain each feature's importance.
we used SVR-RBF, SVR with a radial-basis function (RBF) kernel, GPR-RBF, GPR with an RBF kernel, and JGPR-RBF, GPR with an RBF kernel and joint prediction ( §3) since these models can take into account combinations of features using the RBF kernels, which are useful for combining both domain and semantic features.