Data federation addresses the problem of uniformly accessing multiple, possibly
heterogeneous data sources, by map** them into a unified schema, such as an RDF …

Abstract The Triple Pattern Fragment (TPF) interface is a recent proposal for reducing server
load in Web-based approaches to execute SPARQL queries over public RDF datasets. The …

Data retrieval systems are facing a paradigm shift due to the proliferation of specialized data
storage engines (SQL, NoSQL, Column Stores, MapReduce, Data Stream, and Graph) …

Linked Data initiatives have encouraged the publication of a large number of RDF datasets
created by different data providers independently. These datasets can be accessed using …

Federated query engines allow for linked data consumption using SPARQL endpoints.
Replicating data fragments from different sources enables data re-organization and provides …

Background Several query federation engines have been proposed for accessing public
Linked Open Data sources. However, in many domains, resources are sensitive and access …

Linking Data initiatives have fostered the publication of large number of RDF datasets in the
Linked Open Data (LOD) cloud, as well as the development of query processing …

A key property of linked data, ie, the web-based representation and publication of data as
interconnected labeled graphs, is that it enables querying and navigating through datasets …

In the last years, huge RDF graphs with trillions of triples were created. To be able to
process this huge amount of data, scalable RDF stores are used, in which graph data is …

This dissertation addresses several problems in the context of publishing and consuming
Linked Data. It describes these problems from the perspectives of three stakeholders: the …