- M. Bilotti, Le Zhao, Jamie Callan, Eric Nyberg. 2008. Focused Retrieval over Richly-Annotated Collections. Abstract: This paper introduces a theoretical framework for focused retrieval, based on a formalism called the annotation graph. Annotation graph-based retrieval provides a rich retrieval representation that directly supports query-time constraintchecking of arbitrary relations. This representation can support focused retrieval tasks, such as Question Answering systems, which often have information needs containing constraint types that can not be queried easily under many retrieval models. The problem of annotation graph-based retrieval is mapped onto existing XML element retrieval functionality in the Indri search engine. The remainder of the paper serves to identify and discuss the issues that emerged and illustrate by example what in our opinion constitutes the upcoming research challenges facing the focused retrieval community.
