Character level and word level embedding with bidirectional LSTM - Dynamic recurrent neural network for biomedical named entity recognition from literature

Named Entity Recognition is the process of identifying different entities in a given context. Biomedical Named Entity Recognition (BNER) is the task of extracting chemical names from biomedical texts to support biomedical and translational research. The aim of the system is to extract useful chemical names from biomedical literature text without a lot of handcrafted engineering features. This approach introduces a novel neural network architecture with the composition of bidirectional long short-term memory (BLSTM), dynamic recurrent neural network (RNN) and conditional random field (CRF) that uses character level and word level embedding as the only features to identify the chemical entities. Using this approach we have achieved the F1 score of 89.98 on BioCreAtIvE II GM corpus and 90.84 on NCBI corpus by outperforming the existing systems. Our system is based on the deep neural architecture that uses both character and word level embedding which captures the morphological and orthographic information eliminating the need for handcrafted engineering features. The proposed system outperforms the existing systems without a lot of handcrafted engineering features. The embedding concept along with the bidirectional LSTM network proved to be an effective method to identify most of the chemical entities.