Peer-to-peer file-sharing systems suffer from the overspecification of query results due to the fact that queries are conjunctive and the descriptions of shared files are sparse. ...
This paper addresses the problem of evaluating ranked top-? queries with expensive predicates. As major DBMSs now all support expensive user-defined predicates for Boolean queries...
Data warehouses store large volumes of data according to a multidimensional model with dimensions representing different axes of analysis. OLAP systems (OnLine Analytical Processi...
We study the problem of SPARQL query optimization on top of distributed hash tables. Existing works on SPARQL query processing in such environments have never been implemented in a...