%0 Conference Paper
%A Meng, Xiangfu
%A Ma, Z. M.
%A Yan, Li
%B 18th International World Wide Web Conference
%C Madrid, Spain
%D 2009
%F www2009:103
%P 1021-1021
%T Answering Approximate Queries over Autonomous Web Databases
%U http://www2009.eprints.org/103/
%X To deal with the problem of empty or too little answers returned  from a Web database in response to a user query, this paper  proposes a novel approach to provide relevant and ranked query  results. Based on the user original query, we speculate how much  the user cares about each specified attribute and assign a  corresponding weight to it. This original query is then rewritten as  an approximate query by relaxing the query criteria range. The  relaxation order of all specified attributes and the relaxed degree  on each specified attribute are varied with the attribute weights.  For the approximate query results, we generate users’ contextual  preferences from database workload and use them to create a  priori orders of tuples in an off-line preprocessing step. Only a  few representative orders are saved, each corresponding to a set of  contexts. Then, these orders and associated contexts are used at  query time to expeditiously provide ranked answers. Results of a  preliminary user study demonstrate that our query relaxation and  results ranking methods can capture the user’s preferences  effectively. The efficiency and effectiveness of our approach is  also demonstrated by experimental result.