Exploiting concept hierarchy for result diversification

Abstract

The goal of result diversification is to maximize the coverage of query subtopics while minimizing the redundancy in the search results. Intuitively, it is more desirable for a diversification system to cover independent subtopics since it would retrieve sets of non-overlapped relevant documents, which leads to less redundancy in the search results. Unfortunately, existing diversification methods assume that query subtopics are independent and ignore their relations in the diversification process. To overcome this limitation, we propose to exploit concept hierarchies to extract query subtopics and infer their relations. We then apply axiomatic approaches to derive a structural diversification method that can leverage the subtopic relations in result diversification. Experimental results over an enterprise collection show that the relations among query subtopics are useful to improve the diversification performance.