( National University of Ireland )
Keywords: Metadata,Dashboard,Dashboard design,Dashboard visualization,Best practice
Federated SPARQL Query Frameworks have been actively developed recently. Such a system consists of federated engines as a mediator and a group of SPARQL Endpoints. The mediator receives a query from a client and distributes it to relevant SPARQL Endpoints. As the core component of federation systems, existing evaluation methodologies usually only test the federated engines regardless of the capacity of the SPARQL Endpoints. Most evaluations are chiefly concerned about the speed of the engines response as the sole indicator for federation performance. Hence, the development of federation systems focuses primarily on source selection and join query optimization in the mediator. Several approaches merge a set of sub-queries into one query to reduce the response time. However, SPARQL Endpoints have a restriction to accept a query request in a certain period of time and return the results per query request. We hence conducted an experiment to evaluate federation frameworks by measuring their response time and data transfer between mediator and the SPARQL Endpoints. Additionally, we introduce a set of new metrics that are more suitable to assess the performance of federation frameworks performance in a range of environments.