Fig. 3

The Bi-LSTM-RNN for relation classification. The input sentence is tokenized before it is analyzed by a dependency parser. Tokens are indexed by Arabic numerals. Basic (a.k.a, projective) dependency style is utilized to build a tree. The bold lines in the tree denote the shortest dependency path (SDP) between “gliclazide” and “hepatitis” with their lowest common ancestor “induced”. x _i indicates the input vector of a LSTM unit as shown in Eq. 6 and i corresponds to the index of a token. In the Bi-LSTM-RNN layer, solid arrow lines denote bottom-up and top-down computations along the SDP in the dependency tree. ↑ h _a , ↑ h _b , ↓ h _a , ↓ h _b are listed in Eq. 8