  In this paper, we argue why and how the integration of recommender systems
for research can enhance the functionality and user experience in repositories.
We present the latest technical innovations in the CORE Recommender, which
provides research article recommendations across the global network of
repositories and journals. The CORE Recommender has been recently redeveloped
and released into production in the CORE system and has also been deployed in
several third-party repositories. We explain the design choices of this unique
system and the evaluation processes we have in place to continue raising the
quality of the provided recommendations. By drawing on our experience, we
discuss the main challenges in offering a state-of-the-art recommender solution
for repositories. We highlight two of the key limitations of the current
repository infrastructure with respect to developing research recommender
systems: 1) the lack of a standardised protocol and capabilities for exposing
anonymised user-interaction logs, which represent critically important input
data for recommender systems based on collaborative filtering and 2) the lack
of a voluntary global sign-on capability in repositories, which would enable
the creation of personalised recommendation and notification solutions based on
past user interactions.
