  In this article, we tackle the problem of standard interoperability across
different standardization frameworks, and devise a knowledge-driven approach
that allows for the description of standards and standardization frameworks
into an Industry 4.0 knowledge graph (I40KG). The STO ontology represents
properties of standards and standardization frameworks, as well as
relationships among them. The I40KG integrates more than 200 standards and four
standardization frameworks. To populate the I40KG, the landscape of standards
has been analyzed from a semantic perspective and the resulting I40KG
represents knowledge expressed in more than 200 industrial related documents
including technical reports, research articles, and white papers. Additionally,
the I40KG has been linked to existing knowledge graphs and an automated
reasoning has been implemented to reveal implicit relations between standards
as well as mappings across standardization frameworks. We analyze both the
number of discovered relations between standards and the accuracy of these
relations. Observed results indicate that both reasoning and linking processes
enable for increasing the connectivity in the knowledge graph by up to 80%,
whilst up to 96% of the relations can be validated. These outcomes suggest that
integrating standards and standardization frameworks into the I40KG enables the
resolution of semantic interoperability conflicts, empowering the communication
in smart factories.
