Optimal aggregation algorithms for middleware pdf

For each attribute, there is a sorted list, which lists each object and its grade under that attribute, sorted by grade highest grade rst. There is some monotone aggregation function, or combining rule, such as min or average, that combines the individual grades to obtain an overall grade.

To determine objects that have the best overall grades, the naive algorithm must access every object in the database, to nd its grade under each attribute. For some distributions on grades, and for some monotone aggregation. Continue with Facebook. Sign up with Google. Log in with Microsoft. Bookmark this article. You can see your Bookmarks on your DeepDyve Library. Sign Up Log In. Copy and paste the desired citation format or use the link below to download a file formatted for EndNote.

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You can change your cookie settings through your browser. Ramakrishnan R. McGraw-Hill, New York Sharifzadeh, M. Sleator, D. ACM 28, pp. Yiu M. TKDE 17 6 , — Download references. You can also search for this author in PubMed Google Scholar. Correspondence to Ke Deng. Reprints and Permissions. Instance optimal query processing in spatial networks. Download citation. Received : 19 September Revised : 29 July Accepted : 03 August Published : 04 September Issue Date : June For example, an object can have a color grade, that tells how red it is, and a shape grade, that tells how round it is.

For each attribute, there is a sorted list, which lists each object and its grade under that attribute, sorted by grade highest grade first. Each object is assigned an overall grade, that is obtained by combining the attribute grades using a fixed monotone aggregation function, or combining rule, such as min or average.

To determine the top k objects, that is, k objects with the highest overall grades, the naive algorithm must access every object in the database, to find its grade under each attribute.