Multi-turn intent determination and slot filling with neural networks and regular expressions

摘要

Intent determination and slot filling are two prominent research areas related to natural language understanding (NLU). In a multi-turn NLU system, contextual information from dialogue history is exploited to mitigate the ambiguity of user utterance. State-of-the-art models employ memory networks to encode dialogue context, which is used by neural networks for determining user intent and associated slots. However, these methods rely on a large amount of labelled data, whereas we often have limited labelled data. To address this problem, we propose a multi-task learning model based on neural networks and regular expressions (REs), to jointly perform intent determination and slot filling tasks. The proposed model integrates neural networks with REs to encode domain knowledge and handle cases with a limited amount of labelled data in an end-to-end trainable manner. More specifically, the model employs a pre-trained BERT model to obtain contextual word representations of user utterances. These representations are utilized by a memory network to encode multi-turn information which is shared by the tasks. Furthermore, the convolutional neural network (CNN) and the recurrent neural network (RNN) are applied to contextual word representations and dialogue context for intent determination and slot filling tasks, respectively. These neural networks are then combined with REs which encode domain knowledge about a particular intent or slot value. Finally, the two neural networks are trained simultaneously by minimizing the joint loss. Extensive experiments on Key-Value Retrieval and Frames datasets show that the proposed model outperforms baseline methods in both tasks while requiring modest human effort.