TY - CONF
T1 - Consensus answers for queries over probabilistic databases
T2 - Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Y1 - 2009
A1 - Li,Jian
A1 - Deshpande, Amol
KW - consensus answers
KW - probabilistic and/xor tree
KW - Probabilistic databases
KW - Query processing
KW - rank aggregation
AB - We address the problem of finding a "best" deterministic query answer to a query over a probabilistic database. For this purpose, we propose the notion of a consensus world (or a consensus answer) which is a deterministic world (answer) that minimizes the expected distance to the possible worlds (answers). This problem can be seen as a generalization of the well-studied inconsistent information aggregation problems (e.g. rank aggregation) to probabilistic databases. We consider this problem for various types of queries including SPJ queries, Top-k ranking queries, group-by aggregate queries, and clustering. For different distance metrics, we obtain polynomial time optimal or approximation algorithms for computing the consensus answers (or prove NP-hardness). Most of our results are for a general probabilistic database model, called and/xor tree model, which significantly generalizes previous probabilistic database models like x-tuples and block-independent disjoint models, and is of independent interest.
JA - Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
T3 - PODS '09
PB - ACM
CY - New York, NY, USA
SN - 978-1-60558-553-6
UR - http://doi.acm.org/10.1145/1559795.1559835
M3 - 10.1145/1559795.1559835
ER -