Relevance feedback is a technique employed in information retrieval systems to improve the search quality. There are many different ways of implementing relevance feedback, but common to them all is that a user (directly or indirectly) indicates the relevance of documents returned by the system. This feedback is then used by the system to modify the query in (hopefully) such a way that better results will be returned in the next iteration of the search.
For this research investigation essay, compare different approaches for relevance feedback, analyzing their strengths and weaknesses
Possible starting points for your literature review are given here: