In this article, we provide a comprehensive introduction to knowledge graphs, which have
recently garnered significant attention from both industry and academia in scenarios that …

Large Language Models (LLMs) have taken Knowledge Representation--and the world--by
storm. This inflection point marks a shift from explicit knowledge representation to a renewed …

More and more data in various formats are integrated into knowledge graphs. However,
there is no overview of existing approaches for generating knowledge graphs from …

In this paper, we present the virtual knowledge graph (VKG) paradigm for data integration
and access, also known in the literature as Ontology-based Data Access. Instead of …

Data integration is the dominant use case for RDF Knowledge Graphs. However, Web
resources come in formats with weak semantics (for example, CSV and JSON), or formats …

Ontop is a popular open-source virtual knowledge graph system that can expose
heterogeneous data sources as a unified knowledge graph. Ontop has been widely used in …

Abstract Knowledge graphs are often constructed from heterogeneous data sources, using
declarative rules that map them to a target ontology and materializing them into RDF. When …

In the manufacturing industry, a hydraulic system harnesses liquid fluid power to create
powerful machines. Under the trend of Industry 4.0, the predictive maintenance of hydraulic …

Analyses of products during manufacturing are essential to guarantee their quality. In
complex industrial settings, such analyses require to use data coming from many different …

Abstract The Semantic Web research community understood since its beginning how crucial
it is to equip practitioners with methods to transform non-RDF resources into RDF. Proposals …