281 search results - page 15 / 57 » Querying the Guarded Fragment |
101
Voted
DLOG
2011
14 years 1 months ago
2011
We prove co-N2ExpTime-hardness for conjunctive query entailment in the description logic ALCOIF , thus improving the previously known 2ExpTime lower bound. The result transfers to ...
157
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ICDE
2000
IEEE
15 years 11 months ago
2000
IEEE
Execution plans produced by traditional query optimizers for data integration queries may yield poor performance for several reasons. The cost estimates may be inaccurate, the mem...
DOCENG
2006
ACM
15 years 4 months ago
2006
ACM
Mash-ups extract data fragments from disparate sources, and combine and transform the extracted fragments for display. Currently, mash-up developers tend to employ ad hoc represen...
AAAI
2012
13 years 16 days ago
2012
We tackle the problem of defining a well-founded semantics (WFS) for Datalog rules with existentially quantified variables in their heads and negations in their bodies. In partic...
158
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ICDE
2008
IEEE
15 years 11 months ago
2008
IEEE
We study the problem of answering XPATH queries using multiple materialized views. Despite the efforts on answering queries using single materialized view, answering queries using ...