9th International Conference on Flexible Query Answering Systems (FQAS 2011), Ghent, Belçika, 26 - 28 Ekim 2011, cilt.7022, ss.258-269
Our main motivation is the data access model and aggregation algorithm for middleware by R. Fagin, A. Lotem and M. Naor. They assume data attributes in a variety of repositories ordered by a grade of attribute values of objects. Moreover they assume the user has an aggregation function, which eventually qualifies an object to top-k answers.