This repository contains the core OPC UA ontology and the base UA NodeSet ontology. Both of them are explained in detail in the following publication:
Alexander Perzylo, Stefan Profanter, Markus Rickert, Alois Knoll. OPC UA NodeSet Ontologies as a Pillar of Representing Semantic Digital Twins of Manufacturing Resources. In Proceedings of the IEEE Conference on Emerging Technologies and Factory Automation (ETFA), Zaragoza, Spain, September 2019.