Multiple search engines in database merging

Abstract

A database merging technique is a strategy for combining the results of multiple independent searches into a single cohesive response. While a variety of techniques have been developed to address a range of problem characteristics, our work focuses on environments in which search engines work in isolation. This paper shows that the behavior of two previously developed isolated techniques is indeed independent of the particular search engines that participate in the search. Two very different search engines, SMART and TOPIC, were each used to retrieve documents from five subcollections. The relative effectiveness of the merged result compared to the effectiveness of a corresponding single collection run is comparable for both engines. The effectiveness of the merged result is improved when both search engines search the same five subcolections but participate in a single merging. The improvement is such that this 10-collection merge is sometimes more effective than the single collection run. This last finding suggests that these methods may be able to improve the effectiveness of World Wide Web searches by merging the output from several engines.