Guohui Xiao

Virtual Knowledge Graphs - Applications and Tools

Recently, knowledge graphs have been successfully deployed to overcome the typical difficulties in accessing and integrating data stored in different kinds of sources. In particular, in the Virtual Knowledge Graph (VKG) approach, data is presented in the form of a graph, which is mapped to the underlying data sources, and query answering is based on advanced query transformation techniques. In this tutorial we illustrate the principles underlying the VKG approach, providing an overview of well-established algorithms and techniques, and we discuss relevant use-cases using VKGs. We also introduce the VKG tooling eco-system, including Ontop, the most popular and powerful open-source VKG system, and Ontopic Studio, the easy-to-user VKG designer.

back to overview

Watch Recording


Guohui Xiao is an Associate Professor at the Department of Information Science and Media Studies, Faculty of Social Sciences, University of Bergen (UiB), Norway. Before joining UiB, Guohui was an Assistant Professor at the KRDB Research Centre for Knowledge and Data, Faculty of Computer Science, Free University of Bozen-Bolzano (unibz). He received his Bachelor and Master degrees from Peking University, respectively in 2007 and 2010, and his PhD degree in computer science from Vienna University of Technology, Austria, in 2014. His main research interests include knowledge representation, description logics, semantic Web, database theory and virtual knowledge graphs. In these areas, he authored more than 100 publications, including top-tier international journals and conferences, such as JAIR, SWJ, JWS, IJCAI, AAAI, KR, ICDT, EDBT, ISWC, CIKM, and ECAI, with more than 2700 citations and an h-index of 26. He received the Semantic Web Journal 2016 Outstanding Paper Award for the work of Ontop, the Best In-Use Paper in the 16th International Semantic Web Conference (ISWC 2017), and the Best Paper in the 17th Int. Conf. of the Italian Association for Artificial Intelligence (AIxIA 2018). He is leading the development of the Ontop Virtual Knowledge Graph platform, a popular open-source software for data integration. He is a Co-Founder and Chief Scientist of the Ontopic startup, a spin-off of unibz.