121 search results - page 15 / 25 » On Containment of Conjunctive Queries with Negation |
ICDT
2005
ACM
14 years 1 months ago
2005
ACM
We study the problem of rewriting queries using views in the presence of access patterns, integrity constraints, disjunction, and negation. We provide asymptotically optimal algori...
SIGIR
2012
ACM
11 years 10 months ago
2012
ACM
People are seldom aware that their search queries frequently mismatch a majority of the relevant documents. This may not be a big problem for topics with a large and diverse set o...
JODS
2006
13 years 7 months ago
2006
While providing a uniform syntax and a semistructured data model, XML does not express semantics but only structure such as nesting information. In this paper, we consider the prob...
DEXAW
1998
IEEE
13 years 12 months ago
1998
IEEE
Materialized views offer opportunities for significant performance gain in query evaluation by providing fast access to pre-computed data. The question of when and how to use a ma...
ICIP
2003
IEEE
14 years 1 months ago
2003
IEEE
We have been developing new relevance feedback algorithms for Content-based Image Retrieval (CBIR) that allow the user to achieve more flexible query. In conjunction with the new...