An attention mechanism and multi-granularity-based Bi-LSTM model for Chinese Q&A system

Natural language processing (NLP) is one of the key techniques in intelligent question-answering (Q&A) systems. Although recurrent neural networks and long short-term memory (LSTM) networks exhibit obvious advantages on well-known English Q&A datasets, they still suffer from several defects including indeterminateness, polysemy and the lack of changing morphology in Chinese, which results in complex NLP on large and diverse Chinese Q&A datasets. In this paper, we first analyze limitations of applying LSTM and bidirectional LSTM (Bi-LSTM) models to noisy Chinese Q&A datasets. Then, we focus on integrating attention mechanisms and multi-granularity word segmentation into Bi-LSTM and propose an attention mechanism and multi-granularity-based Bi-LSTM model (AM–Bi-LSTM) which combines the improved attention mechanism with a novel processing of multi-granularity word segmentation to handle the complex NLP in Chinese Q&A datasets. Furthermore, similarity of questions and answers is formulated to implement the quantitative computation which helps to achieve better performance in Chinese Q&A systems. Finally, we verify the proposed model on a noisy Chinese Q&A dataset. The experimental results demonstrate that the novel AM–Bi-LSTM model achieves significant improvement on evaluation metrics of accuracy, mean average precision and so on. Moreover, the experimental results indicate that the novel AM–Bi-LSTM model outperforms baseline methods and other LSTM-based models.