🔑 A Refinement Operator Approach for Key Discovery.
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ROCKER: A Refinement Operator for Key Discovery

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A demo of ROCKER for Data Quality is running at http://rocker.aksw.org. It offers a web interface with accessible APIs. For computations on large datasets, please follow the guide below.

Run from terminal

First, download the full jar package, which also contains all required dependencies. Datasets are available here:

OAEI Benchmark 2011 (artificial data)

DBpedia 3.9 (real data)

To run ROCKER:

java -Xmx8g -jar rocker-1.2.1-full.jar <dataset name> <dataset path with protocol> <class name> <find one key> <fast search> <alpha threshold>


java -Xmx8g -jar rocker-1.2.1-full.jar "restaurant_1" "file:///home/rocker/OAEI_2011_Restaurant_1.nt" "http://www.okkam.org/ontology_restaurant1.owl#Restaurant" false true 1.0

We recommend to run your experiments on a machine with at least 8 GB of RAM.


    <name>University Leipzig, AKSW Maven2 Repository</name>

Java library

You may also download the Java library without dependencies.

Basic usage

Rocker r = null;
r = new Rocker("restaurant_1", "file:///home/rocker/OAEI_2011_Restaurant_1.nt",
        "http://www.okkam.org/ontology_restaurant1.owl#Restaurant", false, true, 1.0);
Set<CandidateNode> results = r.getKeys();


Please refer to the paper T. Soru, E. Marx, A.-C. Ngonga Ngomo, "ROCKER: A Refinement Operator for Key Discovery", in proceedings of the 24th International Conference on World Wide Web, WWW 2015. [PDF] [ACM]

 author = {Soru, Tommaso and Marx, Edgard and {Ngonga Ngomo}, Axel-Cyrille},
 title = {ROCKER: A Refinement Operator for Key Discovery},
 booktitle = {Proceedings of the 24th International Conference on World Wide Web},
 series = {WWW '15},
 year = {2015},
 isbn = {978-1-4503-3469-3},
 location = {Florence, Italy},
 pages = {1025--1033},
 numpages = {9},
 url = {http://doi.acm.org/10.1145/2736277.2741642},
 doi = {10.1145/2736277.2741642},
 acmid = {2741642},
 publisher = {ACM},
 address = {New York, NY, USA},
 keywords = {key discovery, link discovery, linked data, refinement operators, semantic web},