Learning Structural Kernels for Natural Language Processing
Table 5: Learned hyperparameters for the GP SSTK models in the fr-en dataset, with α fixed at 1. λsrc and λtgt are the hyperparameters corresponding to the kernels on the source and target parse trees, respectively. The values shown are averaged over the cross-validation results.
['[EMPTY]', '[ITALIC] λsrc', '[ITALIC] λtgt']
We also inspect the resulting hyperparameters to obtain insights about the features used by the model. The λ values obtained are higher for the target sentence kernels than for the source sentence ones. We can interpret this as the model giving preference to features from the target trees instead of the source trees, which is what we would expect for this task.