Distantly supervised relation extraction employs the alignment of unstructured corpora with knowledge bases to automatically generate labeled data. This method, however, often introduces significant label noise. To address this, multi-instance learning has been widely utilized over the past decade, aiming to extract reliable features from a bag of sentences. Yet, multi-instance learning struggles to effectively distinguish between clean and noisy instances within a bag, thereby hindering the full utilization of informative instances and the reduction of the impact of incorrectly labeled instances. In this paper, we propose a new Meta-Relation enhanced Contrastive learning based method for distantly supervised Relation Extraction named MRConRE. Specifically, we generate a “meta relation pattern” (MRP) for each bag, based on its semantic content, to differentiate between clean and noisy instances. Noisy instances are then transformed into beneficial bag-level instances through relabeling. Subsequently, contrastive learning is employed to develop precise sentence representations, forming the overall representation of the bag. Finally, we utilize a mixup strategy to integrate bag-level information for model training. Our method’s effectiveness is validated through experiments on various benchmarks.
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