Picture of Olaf Hartig Olaf Hartig
Assistant Professor (Universitetslektor)
Division for Database and Information Techniques
Department of Computer and Information Science (IDA)
Linköping University

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Mar. 18, 2018: I have been co-author of two entries in the Encyclopedia of Big Data Technologies, and I have made available preprints of the entries now:

Mar. 12, 2018: We are organizing a tutorial week on Linked Data and Semantic Web technologies at Linköping University.

Feb. 18, 2018: Our ISWC 2017 best research paper about "A Formal Framework for Comparing Linked Data Fragments" (preprint) has been invited to the Sister Conference Best-Paper Track at the 27th International Joint Conference on Artificial Intelligence (IJCAI), which will take place in July in Stockholm.

Dec. 22, 2017: Our research paper about the "Semantics and Complexity of GraphQL" (co-authored with Jorge Pérez from the Universidad de Chile) got accepted to The Web Conference (27th International World Wide Web Conference - WWW 2018). We have made available a PDF file preprint of this paper.

Dec. 21, 2017: The official report for our Dagstuhl seminar on "Federated Semantic Data Management" is online now.

Nov. 14, 2017: According to Google Scholar, my publications now have attracted more than 2000 citations and I have reached an h-index of 20.

Oct. 27, 2017: Together with Ian Letter and Jorge Pérez (both Universidad de Chile), I have won the Best Research Paper Award at the 16th International Semantic Web Conference (ISWC) for our paper "A Formal Framework for Comparing Linked Data Fragments." Read a brief blog post about the paper or read the paper itself. Additionally, I have also won the People's Choice Best Poster Award at the conference for my poster about "RDF* and SPARQL*: An Alternative Approach to Annotate Statements in RDF" (check out the poster paper).

Oct. 18, 2017: I have started a blog which I will use to write about events, ideas, and results related to my research.

Oct. 10, 2017: I am a Co-Editor of a section in the upcoming Encyclopedia of Big Data Technologies. The section that I co-edit (together with Philippe Cudré-Mauroux) will be on "Big Semantic Data Processing."

Sep. 8, 2017: I will be the Co-Chair of the Semantic Data Management and Big Data Track of the 15th Extended Semantic Web Conference (ESWC). The conference takes place next year in June in Heraklion, Crete.

Research Interests

I am interested in problems related to the management of data and databases. My focus in this broad context is on data on the Web (Semantic Web and Linked Data, in particular) and on graph data, as well as on problems in which the data is distributed over multiple, autonomous and/or heterogeneous sources (keyword: federated data management). Other keywords that appear in some of my work are data provenance and data quality. Regarding all of these topics, my interests range from systems-building related research (e.g., efficient storage of datasets and databases, query processing, and query optimization) all the way to theoretical foundations (e.g., complexity and expressive power of query languages).


Here is my academic CV: PDF file

Selected Publications

This following list contains selected publications. There is also a complete list of all my publications.

Program Committees

Additional Activities


Ongoing and upcoming courses at LiU for which I am the course leader:

Earlier courses at LiU for which I was the course leader:

Other courses at LiU that I am or was involved in:

Earlier courses at UWaterloo for which I was the course leader:

Earlier practicals and seminars at HU Berlin for which I was responsible as a teaching assistant: