Leveraging Semantic Type Dependencies for Clinical Named Entity Recognition.
This paper addresses the underutilization of domain-specific semantic knowledge in clinical named entity recognition (NER). We propose a novel modeling approach that explicitly incorporates semantic type dependencies from the Unified Medical Language System (UMLS) to enhance contextual understanding. Specifically, we design a single-pass matrix encoding mechanism that represents multi-type semantic relations—e.g., “Disease–Symptom” or “Drug–Dosage”—between entity spans and context tokens as structured matrices, seamlessly integrated into a BiLSTM-GCN-CRF architecture. The method is compatible with clinical pretrained embeddings (e.g., BERT, BioBERT, UMLSBERT) without requiring additional fine-tuning. Evaluated on standard clinical benchmarks—including i2b2 and ShARe/CLEF—it achieves significant improvements in fine-grained NER performance, with average F1-score gains of 1.8–3.2 percentage points. Results demonstrate that explicit modeling of domain-specific semantic dependencies substantially enhances clinical NER accuracy and advances knowledge-guided NER paradigms.