Ephedra: Efficiently Combining RDF Data and Services Using SPARQL Federation

@inproceedings{Nikolov2017EphedraEC,
  title={Ephedra: Efficiently Combining RDF Data and Services Using SPARQL Federation},
  author={Andriy Nikolov and Peter Haase and Johannes Trame and Artem Kozlov},
  booktitle={KESW},
  year={2017}
}
Knowledge graph management use cases often require addressing hybrid information needs that involve multitude of data sources, multitude of data modalities (e.g., structured, keyword, geospatial search), and availability of computation services (e.g., machine learning and graph analytics algorithms). Although SPARQL queries provide a convenient way of expressing data requests over RDF knowledge graphs, the level of support for hybrid information needs is limited: existing query engines usually… 
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