Improving Aspect Term Extraction with Bidirectional Dependency Tree Representation

Aspect term extraction is one of the important subtasks in aspect-based sentiment analysis. Previous studies have shown that dependency tree structure representation is promising for this task. In this paper, we propose a novel bidirectional dependency tree network to extract dependency structure features from the given sentences. The key idea is to explicitly incorporate both representations gained separately from the bottom-up and top-down propagation on the given dependency syntactic tree. An end-to-end framework is proposed to integrate the embedded representations and BiLSTM plus CRF to learn both tree-structured and sequential features to solve the aspect term extraction problem. Experimental results demonstrate that the proposed model outperforms state-of-the-art baseline models on four benchmark SemEval datasets.