Quantifying the Connectivity of a Semantic Warehouse

In many applications one has to fetch and assemble pieces of information coming from more than one SPARQL endpoints. In this paper we describe the corresponding requirements and challenges, and then we present a process for constructing such a semantic warehouse. We focus on the aspects of quality and value of the warehouse, and for this reason we introduce various metrics for quantifying its connectivity, and consequently its ability to answer complex queries. We demonstrate the behavior of these metrics in the context of a real and operational semantic warehouse. The results are very promising: the proposed metrics-based matrixes allow someone to get an overview of the contribution (to the warehouse) of each source and to quantify the benefit of the entire warehouse. The later is useful also for monitoring the quality of the warehouse after each reconstruction.