We present an improved oracle for the distance sensitivity problem. The goal is to preprocess a directed graph G = (V, E) with non-negative edge weights to answer queries of the f...
We study efficient query processing in distributed web search engines with global index organization. The main performance bottleneck in this case is due to the large amount of i...
A tuple t1 of relation R subsumes tuple t2 of R, with respect to a query Q if for every database, tuple t1 derives all, and possibly more, answers to query Q than derived by tuple ...
Severalmethodshavebeenproposedto compile recursive Datalog programs. The most well-known perform a rewriting of rules using MAGIC or PROBLEM predicates in order to push selections...
In XML search systems twig queries specify predicates on node values and on the structural relationships between nodes, and a key operation is to join individual query node matche...