Experiment on Pseudo Relevance Feedback Method Using Taylor Formula at NTCIR-3 Patent Retrieval Task

Pseudo relevance feedback is empirically known as a useful method for enhancing retrieval performance. For example, we can apply the Rocchio method, which is well-known relevance feedback method, to the results of an initial search by assuming that the top-ranked documents are relevant a priori. In this paper, for searching NTCIR-3 patent test collection through pseudo feedback, we try to employ two relevance feedback mechanism; (1) the Rocchio method, and (2) a new method that is based on Taylor formula of linear search functions. The test collection consists of near 700,000 records including full text of Japanese patent materials. Unfortunately, effectiveness of our pseudo feedback methods was not empirically observed at all in the experiment. One of the reasons may be that all words from the documents to be assumed as relevant were used without any selection process.