Weighted Word Pairs for query expansion

•A graph of terms can be effectively used for query expansion.•Such a graph is extracted from documents thanks to a LDA based methodology.•Proposed method achieves good performances on standard datasets.

This paper proposes a novel query expansion method to improve accuracy of text retrieval systems. Our method makes use of a minimal relevance feedback to expand the initial query with a structured representation composed of weighted pairs of words. Such a structure is obtained from the relevance feedback through a method for pairs of words selection based on the Probabilistic Topic Model. We compared our method with other baseline query expansion schemes and methods. Evaluations performed on TREC-8 demonstrated the effectiveness of the proposed method with respect to the baseline.