GEMS-RAG: graph-grounded multimodal RAG for engineering standards
GEMS-RAG is a framework that combines hierarchical parsing, fine-grained visual entity extraction, multimodal knowledge-graph construction, and graph-grounded hybrid retrieval to enable grounded reasoning over complex, multimodal engineering standards. Evaluated on the Manual on Uniform Traffic Control Devices (MUTCD), GEMS-RAG improves retrieval effectiveness and question-answering performance compared with text-only, multimodal, and graph-based RAG baselines.