In this paper, we characterize the logical correspondence between conjunctive queries and concept descriptions. We exhibit a necessary and sufficient condition for the compilation of a conjunctive query into an equivalent ALE concept description. We provide a necessary and sufficient condition for the approximation of conjunctive queries by maximally subsumed ALN concept descriptions.

In this paper, we characterize the logical correspondence between conjunctive queries and concept descriptions. We exhibit a necessary and suucient condition for the compilation of a conjunctive query into an equivalent ALE concept description. We provide a necessary and suucient condition for the approximation of conjunctive queries by maximally subsumed ALN concept descriptions.

We present in this paper the use of two auto-adaptive information-fusion methods for a satellite image classi-cation problem. These methods come from possibility theory. Several information-fusion methods are available for diierent kinds of problems. Auto-adaptive fusion allows to have a fusion which modiies its behaviour according to information to be merged. It has a conjunctive behaviour whe...

We investigate an extension of conjunctive regular path queries in which path properties and path relations are defined by visibly pushdown automata. We study the problem of query evaluation for extended conjunctive visibly pushdown path queries and their subclasses, and give a complete picture of their combined and data complexity. In particular, we introduce a weaker notion called extended co...