DSP: Discriminative Soft Prompts for Zero-Shot Entity and Relation Extraction

Bo Lv, Xin Liu, Shaojie Dai, Nayu Liu, Fan Yang, Ping Luo, Yue Yu

Findings: Information Extraction Findings Paper

Session 4: Information Extraction (Virtual Poster)
Conference Room: Pier 7&8
Conference Time: July 11, 11:00-12:30 (EDT) (America/Toronto)
Global Time: July 11, Session 4 (15:00-16:30 UTC)
Keywords: zero/few-shot extraction
TLDR: Prompt-based methods have shown their efficacy in transferring general knowledge within pre-trained language models (PLMs) for low-resource scenarios. Typically, prompt-based methods convert downstream tasks to cloze-style problems and map all labels to verbalizers. However, when applied to zero-sho...
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Abstract: Prompt-based methods have shown their efficacy in transferring general knowledge within pre-trained language models (PLMs) for low-resource scenarios. Typically, prompt-based methods convert downstream tasks to cloze-style problems and map all labels to verbalizers. However, when applied to zero-shot entity and relation extraction, vanilla prompt-based methods may struggle with the limited coverage of verbalizers to labels and the slow inference speed. In this work, we propose a novel Discriminate Soft Prompts (DSP) approach to take advantage of the prompt-based methods to strengthen the transmission of general knowledge. Specifically, we develop a discriminative prompt method, which reformulates zero-shot tasks into token discrimination tasks without having to construct verbalizers. Furthermore, to improve the inference speed of the prompt-based methods, we design a soft prompt co-reference strategy, which leverages soft prompts to approximately refer to the vector representation of text tokens. The experimental results show that, our model outperforms baselines on two zero-shot entity recognition datasets with higher inference speed, and obtains a 7.5\% average relation F1-score improvement over previous state-of-the-art models on Wiki-ZSL and FewRel.