N-best Rescoring for Parsing Based on Dependency-Based Word Embeddings

Yu-Ming Hsieh ； Wei-Yun Ma

《中文計算語言學期刊》 21卷2期 (2016/12) Pp. 19-33

摘要

Rescoring approaches for parsing aims to re-rank and change the order of parse trees produced by a general parser for a given sentence. The re-ranking performance depends on whether or not the rescoring function is able to precisely estimate the quality of parse trees by using more complex features from the whole parse tree. However it is a challenge to design an appropriate rescoring function since complex features usually face the severe problem of data sparseness. And it is also difficult to obtain sufficient information requisite in re-estimatation of tree structures because existing annotated Treebanks are generally small-sized. To address the issue, in this paper, we utilize a large amount of auto-parsed trees to learn the syntactic and sememtic information. And we propose a simple but effective score function in order to integrate the scores provided by the baseline parser and dependency association scores based on dependency-based word embeddings, learned from auto-parsed trees. The dependency association scores can relieve the problem of data sparseness, since they can be still calculated by word embeddings even without occurrence of a dependency word pair in a corpus. Moreover, semantic role labels are also considered to distinct semantic relation of word pairs. Experimental results show that our proposed model improves the base Chinese parser significantly.

關鍵字

Word Embedding ； Parsing ； Word Dependency ； Rescoring

參考文獻

Hsieh, Y.M.,Yang, D.C.,Chen, K.J.(2007).Improve Parsing Performance by Self-Learning.Computational Linguistics and Chinese Language Processing (IJCLCLP).12(2),195-216.

Bansal, M.,Gimpel, K.,Livescu, K.(2014).Tailoring continuous word representations for dependency parsing.Proceedings of ACL 2014.(Proceedings of ACL 2014).

Charniak, E.,Johnson, M.(2005).Coarse-to-fine n-best parsing and MaxEnt discriminative reranking.Proceedings of ACL 2005.(Proceedings of ACL 2005).

Chen, D.,Manning, C.D.(2014).A fast and accurate dependency parser using neural networks.Proceedings of EMNLP 2014.(Proceedings of EMNLP 2014).

Chen, L.(2008).Autolabeling of VN Combination Based on Multi-classifier.Journal of Computer Engineering.24(5),79-81.