Tibetan word segmentation method based on CNN-BiLSTM-CRF model

We propose a Tibetan word segmentation method based on CNN-BiLSTM-CRF model that merely uses the characters of sentence as the input so that the method does not need large-scale corpus resources and manual features for training. Firstly, we use convolution neural network to train character vectors. Then the character vectors are searched through the character lookup table to form a matrix C by stacking searched results. Then the convolution operation between the matrix C and multiple filter matrices is carried out to obtain the character-level features of each Tibetan word by maximizing the pooling. We input the character vector into the BiLSTM-CRF model, which is suitable for Tibetan word segmentation through the highway network, for getting a Tibetan word segmentation model that is optimized by using the character vector and CRF model. For Tibetan language with rich morphology, fewer parameters and faster training time make this model better than BiLSTM-CRF model in the performance of character level. The experimental results show that character input is sufficient for language modeling. The robustness of Tibetan word segmentation is improved by the model that can achieves 95.17% of the F value.