Olaf Hartig

📣 Postdoc position on Virtual Knowledge Graph Integration at Linköping University

I'm looking for a postdoc to actively lead research in two complementary projects on foundations & techniques for querying federations of KG views of heterogeneous data sources.

👉 Further info: liu.se/en/work-at-l...

Peter, I very much enjoyed the DSDSD talks today. Thanks for continuing the series!!

GitHub - hartig/ExploratoryQueryingSessions: A collection of exploratory querying sessions discovered in Wikidata SPARQL logs. A collection of exploratory querying sessions discovered in Wikidata SPARQL logs. - hartig/ExploratoryQueryingSessions

... and we also have a repo with a collection of exploratory querying sessions that we extracted (manually) in the context of this work: github.com/hartig/Explo...

Finally, our VLDB paper is out: "Exploring Exploratory Querying." — A research vision related to a new way of querying, including new types of users.

vldb.org/pvldb/volume...

This paper is the result of discussions we had during a Shonan meeting late last year.

The SPARQL endpoint of the Nobel Prize dataset:
www.nobelprize.org/about/linked...

Nyckeln till framtidens smarta informationshantering | Knut och Alice Wallenbergs Stiftelse En stor mängd av den information som företag, myndigheter eller konsumenter behöver komma åt ligger i dag utspridd på nätet hos olika aktörer. Av olika skäl är det inte alltid möjligt att slå samman o...

@olafhartig.bsky.social och hans forskargrupp har en vision om att man ska kunna samla information som i dag ligger utspridd på webben inom en organisation. Det ska ske virtuellt, så att varje aktör behåller kontrollen över sin egen information #forskning #vetenskap
tinyurl.com/z9ds5ku8

The key to smart information management | Knut and Alice Wallenberg Foundation Much of the information that businesses, public agencies or consumers need to access is currently in the hands of multiple players spread across the Internet. For various reasons, it is not always pos...

@olafhartig.bsky.social and his #research team have a vision that we should be able to bring together information that is currently scattered across the Web by integrating the info virtually so that each player retains control over their own information #science @liu.se
tinyurl.com/yssef6u3

Here is the paper: olafhartig.de/files/MinOoH...

Super glad to receive the Best Research Paper Award at #ESWC2025 together with Sitt Min Oo for our work on providing a formal foundation for mapping languages for Knowledge Graph construction.

The @liu.se Semantic Web gang at the #ESWC2025 conference.

Min Oo is presenting our work on providing a formal foundation for Knowledge Graph construction at #ESWC2025

Related to our approach to represent and to query lists as composite values in RDF-based Knowledge Graphs, I developed a tool to convert RDF files in which lists are represented as RDF collections (rdf:List) into files that use our cdt:List approach.

Repo and download: github.com/hartig/SPARQ...

Researching graph databases, SPARQL engines, or stores for Knowledge Graphs? Submit to TGDK Special Issue: Data Management for (Knowledge) Graphs. Deadline July 1st, 2025. Resources, experience reports and extended workshop/conference papers welcome. CfP: bit.ly/4luAUXZ

An Algebraic Foundation for Knowledge Graph Construction (Extended Version) Although they exist since more than ten years already, have attracted diverse implementations, and have been used successfully in a significant number of applications, declarative mapping languages fo...

So far, declarative mapping languages for knowledge graph construction (RML and the likes) have lacked a solid formal foundation 😶‍🌫️

⚡ Our latest work, accepted for #ESWC2025, changes that: We introduce an algebra for mappings, provide a formal semantics for RML, and more.

🔎 arxiv.org/abs/2503.10385

...now also on arXiv!

"Towards Computer-Using Personal Agents"
arxiv.org/abs/2503.15515

CoopIS, 31st Int'l. Conf. on Cooperative Information Systems Knowledge Graphs, Data, Information, and Knowledge Engineering, Inductive Learning, Machine-Learning and Knowledge Discovery, Process Analytics and Technology, Semantic Interoperability and Open Standards, Human-centric Security and Privacy in Information Systems, Internet of Things and Digital Twins, Architecture and Management of Information Systems, Human Aspects and Social Interaction in Information Systems, Services and Cloud in Information Systems, Applications of Human-centric Information Systems in a Digital World, Software Engineering for Information Systems

📣 We are looking to expand the Program Committee for this year's CoopIS conference and are calling for self- nominations. If interested, please nominate yourself: forms.gle/CYGYkeqVDBLR... ✍️

ℹ️ More info about CoopIS'25, the 31st Int. Conf. on Cooperative Information Systems: coopis.scitevents.org

In a recent #Dagstuhl seminar we developed a research roadmap towards Computer-Using Personal Agents (CUPAs), automating complex tasks like today's Computer-Using Agents, but including context via controlled access to personal knowledge graphs. Our vision paper: openaccess.city.ac.uk/id/eprint/34...

Nice achievement. Congratulations!

I just saw that DBLP (@dblp.org) has recently started to provide a public query service for everyone to run SPARQL queries over their database with information about computer science publications. Each author page includes links to relevant example queries. Very nice!
blog.dblp.org/2024/09/09/i...

Congratulations Elena! Very well deserved!

Thank you all for a great week in #Dagstuhl, here's the traditional photo 😉

www.dagstuhl.de/25051

Arrived at Castle Dagstuhl for a week of discussions around "Trust and Accountability in Knowledge Graph-Based AI for Self Determination" www.dagstuhl.de/25051

Congratulations @hannes.muehleisen.org !!

Nice! I should try it with road bikes 🚴🏼‍♂️ /cc @klinovp.bsky.social

It may be a way to quickly provide GQL support on top of a Gremlin server. There is a library for it: github.com/WSaffery/GQL...
I can see, however, that the performance of such a setup may not be able to compete with any more direct implementation of GQL.

Join the Apache TinkerPop Discord Server! Apache TinkerPop is an open source graph computing framework and the home of the Gremlin graph query language. | 1333 members

Interested in translating from the recently-standardized graph database language GQL to Gremlin ? Next Monday (Nov.25), the Tinkerpop community has a talk for you.
discord.gg/tinkerpop?ev...

I have heard the waters here are calmer. Ready to start new.