Linked Data-Fu

Features

Data Manipulation

The ldfu system supports high-frequency data access and manipulation via HTTP CRUD methods (Linked Data and Linked Data Platform). Request rules specify how to access data and traverse links. High-frequency access is suitable for Internet of Things/Web of Things scenarios.

Querying

The ldfu system includes a streaming query engine for conjunctive queries (Basic Graph Pattern queries) over RDF data.

Reasoning

The ldfu system provides functionality for large-scale data integration, including reasoning with ontologies. Deduction rules specify how to derive new data from existing data. Reasoning supports the integration of data from multiple sources.

Mailing List

For discussion of ldfu use the mailing list at Google Groups.

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Publications

Andreas Harth, Tobias Käfer. "Linked Data Techniques for the Web of Things". Tutorial at the 8th International Conference on the Internet of Things (IoT 2018), October 15, 2018, Santa Barbara, California, USA.
Tobias Käfer, Andreas Harth. "Specifying, Monitoring, and Executing Workflows in Linked Data Environments". International Semantic Web Conference 2018 (ISWC 2018), October 8-12, 2018, Monterey, California, USA. arXiv preprint (PDF)
Tobias Käfer, Andreas Harth. "Rule-based Programming of User Agents for Linked Data". WWW2018 Workshop on Linked Data on the Web (LDOW2018), April 23, 2018. Lyon, France.
Andreas Harth, Tobias Käfer. "Specifying and Executing Application Behaviour with Condition-Request Rules". ISWC2017 workshop on Decentralizing the Semantic Web, October 22, 2017, Vienna, Austria.
Andreas Harth, Tobias Käfer. "Rule-based Processing of Dynamic Linked Data". Tutorial at the European Semantic Web Conference (ESWC 2017), May 28 - June 1, 2017 in Portorož, Slovenia.
Felix Leif Keppmann, Maria Maleshkova, Andreas Harth. "Semantic Technologies for Realising Decentralised Applications for the Web of Things". 21st International Conference on Engineering of Complex Computer Systems, Nov 6-8, 2016, Dubai, UAE.
Andreas Harth, Tobias Käfer. "Towards Specification and Execution of Linked Systems". 28. GI-Workshop Grundlagen von Datenbanken, May 24 - 27, 2016, Nörten-Hardenberg, Germany.
Felix Leif Keppmann, Tobias Käfer, Steffen Stadtmüller, René Schubotz and Andreas Harth. "High Performance Linked Data Processing for Virtual Reality Environments". International Semantic Web Conference (Posters & Demos). ISWC 2014, Riva del Garda, Italy.
Felix Leif Keppmann, Tobias Käfer, Steffen Stadtmüller, René Schubotz and Andreas Harth. "Integrating Highly Dynamic RESTful Linked Data APIs in a Virtual Reality Environment". International Symposium on Mixed and Augmented Reality (Posters & Demos). ISMAR 2014, Munich, Germany.
Andreas Harth, Craig Knoblock, Steffen Stadtmüller, Rudi Studer and Pedro Szekely. "On-the-fly Integration of Static and Dynamic Linked Data". Fourth International Workshop on Consuming Linked Data (COLD 2013). Co-located with ISWC 2013, Sydney, Australia.
Steffen Stadtmüller, Sebastian Speiser, Andreas Harth, Rudi Studer. "Data-Fu: A Language and an Interpreter for Interaction with Read/Write Linked Data". WWW 2013, Rio de Janerio, Brasil. Please note that we have renamed the system to "Linked Data-Fu" to avoid name clashes with other projects.
Steffen Stadtmueller, Andreas Harth. "Towards Data-driven Programming for RESTful Linked Data". First Workshop on Programming the Semantic Web, co-located with International Semantic Web Conference, 2012, Boston, MA, USA. (Slides)

Data Sources

The list contains Linked Data sources with relatively high update frequencies.

Linked LA Metro: Linked Data wrapper to the Los Angeles Metro API (live LA Metro data)

Current positions of buses on line 720 (updated every few minutes)

Linked Eventful: Linked Data wrapper to the Eventful API (live Eventful data)
- Events in Los Angeles (updated every few hours)
Linked Wikimapia: Linked Data wrapper to Wikimapia (live Wikimapia data)
Linked OpenStreetMap: Linked Data wrapper to the OpenStreetMap API (live OpenStreetMap data)
Linked CrunchBase: Linked Data wrapper to CrunchBase Data (live CrunchBase data)
Linked LastFM: Linked Data wrapper to Last.fm Web Services (currently down)
@@@Your live Linked Data source here

Frequently Asked Questions

Do you separate link traversal specifications from query procesing?: Yes, we do. Request rules can be used to specify link traversal, while a SPARQL query is evaluated on the resulting data in a streaming fashion. Since 2012.
I have read that Linked Data-Fu is doing remote procedure calls (RPCs). Is this true?: The head of request rules contains HTTP requests. So you could include POST requests that do RPC-style interaction. However, we suggest to use state manipulation CRUD operations following the HTTP semantics. Since 2012.

Team

Andreas Harth (lead)
Felix Leif Keppmann
Tobias Käfer
Maribel Acosta

Benedikt Kämpgen (user #1)
Sebastian Speiser (retired)
Steffen Stadtmüller (retired)

Acknowledgements

Linked Data-Fu has been supported by the German Ministry for Education and Research (project ARVIDA, reference architecture for virtual services and applications), the European Commission (FP7 project i-VISION, virtual aircraft cockpit design) and the Office of Naval Research Global.

News

2017-03-27: Added frequently asked questions.
2017-01-31: Added links to data sources.
2016-05-20: Version 0.9.10 available as part of a closed beta program.
2015-09-30: Version 0.9.6 available as part of a closed beta program.
2015-05-23: Experiments started (see also: ldfu robots page).
2015-02-05: Beta program started.

Welcome to ldfu!