  Low reliability and availability of public SPARQL endpoints prevent
real-world applications from exploiting all the potential of these querying
infras-tructures. Fragmenting data on servers can improve data availability but
degrades performance. Replicating fragments can offer new tradeoff between
performance and availability. We propose FEDRA, a framework for querying Linked
Data that takes advantage of client-side data replication, and performs a
source selection algorithm that aims to reduce the number of selected public
SPARQL endpoints, execution time, and intermediate results. FEDRA has been
implemented on the state-of-the-art query engines ANAPSID and FedX, and
empirically evaluated on a variety of real-world datasets.
