Hybrid semi-Markov CRF for Neural Sequence Labeling

Zhixiu Ye, Zhen-Hua Ling


Abstract
This paper proposes hybrid semi-Markov conditional random fields (SCRFs) for neural sequence labeling in natural language processing. Based on conventional conditional random fields (CRFs), SCRFs have been designed for the tasks of assigning labels to segments by extracting features from and describing transitions between segments instead of words. In this paper, we improve the existing SCRF methods by employing word-level and segment-level information simultaneously. First, word-level labels are utilized to derive the segment scores in SCRFs. Second, a CRF output layer and an SCRF output layer are integrated into a unified neural network and trained jointly. Experimental results on CoNLL 2003 named entity recognition (NER) shared task show that our model achieves state-of-the-art performance when no external knowledge is used.
Anthology ID:
P18-2038
Volume:
Proceedings of the 56th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)
Month:
July
Year:
2018
Address:
Melbourne, Australia
Editors:
Iryna Gurevych, Yusuke Miyao
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
235–240
Language:
URL:
https://aclanthology.org/P18-2038
DOI:
10.18653/v1/P18-2038
Bibkey:
Cite (ACL):
Zhixiu Ye and Zhen-Hua Ling. 2018. Hybrid semi-Markov CRF for Neural Sequence Labeling. In Proceedings of the 56th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers), pages 235–240, Melbourne, Australia. Association for Computational Linguistics.
Cite (Informal):
Hybrid semi-Markov CRF for Neural Sequence Labeling (Ye & Ling, ACL 2018)
Copy Citation:
PDF:
https://aclanthology.org/P18-2038.pdf
Poster:
 P18-2038.Poster.pdf
Code
 ZhixiuYe/HSCRF-pytorch
Data
CoNLLCoNLL 2003