Two-stage NER for tweets with clustering

One main challenge of Named Entities Recognition (NER) for tweets is the insufficient information in a single tweet, owing to the noisy and short nature of tweets. We propose a novel system to tackle this challenge, which leverages redundancy in tweets by conducting two-stage NER for multiple similar tweets. Particularly, it first pre-labels each tweet using a sequential labeler based on the linear Conditional Random Fields (CRFs) model. Then it clusters tweets to put tweets with similar content into the same group. Finally, for each cluster it refines the labels of each tweet using an enhanced CRF model that incorporates the cluster level information, i.e., the labels of the current word and its neighboring words across all tweets in the cluster. We evaluate our method on a manually annotated dataset, and show that our method boosts the F1 of the baseline without collectively labeling from 75.4% to 82.5%.

► We study the task of named entity recognition for tweets, which is challenging owing to the dearth of information in a single tweet. ► We propose a novel system that conducts two-stage labeling to exploit the redundancy in similar tweets. ► We evaluate our method on a human annotated dataset, and show that our method outperforms the strong baseline without collectively labeling.