We’re delighted to announce that Katja Hose has received the Best In-Use Paper Award at the International Semantic Web Conference (ISWC) 2026 in Bari for the paper “Evolving FedX: High-Performance SPARQL Federation in the Eclipse RDF4J Ecosystem”, co-authored with Andreas Schwarte and Peter Haase from metaphactory.

The International Semantic Web Conference is the premier international forum for the Semantic Web and Linked Data community, bringing together researchers, practitioners, and industry specialists to discuss, advance, and shape the future of semantic technologies.

Congratulations Katja, Andreas and Peter!

Abstract

Knowledge graphs are key components in many modern applications, from federated and virtual knowledge graphs for data integration to their use in AI. These use cases depend on robust federation techniques that provide efficient, reliable access to distributed graph data. Since its introduction, FedX has become one of the most widely used federation engines and a core component of Eclipse RDF4J since 2019, benefiting from a mature open-source ecosystem and continuous community-driven refinement. Over time, FedX has evolved to incorporate advanced optimization techniques that improve query processing efficiency. In this paper, we present and discuss several optimizations developed through extensive practical experience and feedback from the RDF4J user community. These include advances in source selection, such as leveraging ontologies to identify semantically relevant sources, as well as improvements in query execution, including progressing bind joins and left joins. We demonstrate the practical impact of these techniques through a comprehensive experimental evaluation, showing significant performance gains in complex federated scenarios.

About Katja Hose

Katja Hose is a Professor at TU Wien Informatics, where she leads the Data Management and Knowledge-Driven AI Lab. She also serves as Head of the Research Unit Data Management. She had prior positions at Aalborg University, the Max Planck Institute for Informatics, and received her PhD from Ilmenau University of Technology.

Her research is rooted in data management and knowledge engineering, with a particular focus on graph data management, knowledge graphs, data integration, and applied machine learning.

She has co-authored more than 150 peer-reviewed publications and serves on the editorial boards of leading journals such as the VLDB Journal, the Semantic Web Journal (SWJ), and Transactions on Graph Data and Knowledge (TGDK). In addition, she contributes to the international research community in various organizational and program committee roles at flagship conferences including VLDB, SIGMOD, EDBT, ISWC, ESWC, and TheWebConf.

Learn more about Katja in our 5QW-Interview.

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