Research on Machine Reading Comprehension Integrating Long-Distance Entity Relations and Entity-Level Linguistic Cues
摘要
Machine reading comprehension (MRC) requires models to integrate evidence scattered across long contexts. In many MRC settings, named entities provide strong linguistic anchors for linking distant evidence and narrowing candidate answer spans. Although pre-trained language models (PLMs) such as BERT achieve strong performance, they may not explicitly model sparse long-distance entity relations that span multiple sentences. We propose an entity-graph-enhanced MRC framework that constructs an entity co-occurrence graph from each input context (without relying on external knowledge bases), encodes the graph with a graph convolutional network (GCN), and fuses entity representations with PLM token representations for answer extraction. Two graph construction strategies—sentence-level co-occurrence and sliding-window co-occurrence weighted by normalized pointwise mutual information (NPMI)—are compared. Experiments on the DuReader dataset show consistent improvements over BERT/PERT/MacBERT baselines measured by BLEU-4 and ROUGE-L, and the sliding-window graph yields the best overall performance.