  Search systems are increasingly used for gaining knowledge through accessing
relevant resources from a vast volume of content. However, search systems
provide only limited support to users in knowledge acquisition contexts.
Specifically, they do not fully consider the knowledge gap which we define as
the gap existing between what the user knows and what the user intends to
learn. The effects of considering the knowledge gap for knowledge acquisition
tasks remain largely unexplored in search systems. We propose to model and
incorporate the knowledge gap into search algorithms. We plan to explore to
what extent the incorporation of the knowledge gap leads to an improvement in
the performance of search systems in knowledge acquisition tasks. Furthermore,
we aim to investigate and design a metric for the evaluation of the search
systems' performance in the context of knowledge acquisition tasks.
