Embedding based Query Expansion for Weighted Sequential Dependence Retrieval Model
Although information retrieval models based on Markov Random Fields (MRF) such as Sequential Dependence Model and Weighted Sequential Dependence Model (WSDM) have been shown to outperform bag of words probabilistic and language modeling retrieval models by taking into account term dependencies, it is not known how to effectively account for term dependencies in query expansion methods based on pseudo relevance feedback (PRF) for retrieval models of this type. In this paper, we propose Semantic Weighted Dependence Model (SWDM) a PRF based query expansion method for WSDM, which utilizes distributed low dimensional word representations (i.e. word embeddings) Our method finds the closest unigrams to each query term in the embedding space and top retrieved documents and directly incorporates them into the retrieval function of WSDM. Experiments on TREC datasets indicate statistically significant improvement of SWDM over state of the art MRF retrieval models, PRF methods for MRF retrieval models and embedding based query expansion methods for bag of words retrieval models.
SIGIR