title: Uncovering the information core in recommender systems.
abstract: With the rapid growth of the Internet and overwhelming amount of information that people are confronted with, recommender systems have been developed to effectively support users' decision-making process in online systems. So far, much attention has been paid to designing new recommendation algorithms and improving existent ones. However, few works considered the different contributions from different users to the performance of a recommender system. Such studies can help us improve the recommendation efficiency by excluding irrelevant users. In this paper, we argue that in each online system there exists a group of core users who carry most of the information for recommendation. With them, the recommender systems can already generate satisfactory recommendation. Our core user extraction method enables the recommender systems to achieve 90% of the accuracy of the top-L recommendation by taking only 20% of the users into account. A detailed investigation reveals that these core users are not necessarily the large-degree users. Moreover, they tend to select high quality objects and their selections are well diversified.
authors.affiliation: 1] Web Sciences Center, University of Electronic Science and Technology of China, Chengdu 611731, P.R. China [2] State Key Laboratory of Networking and Switching Technology, Beijing 100876, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zeng
authors.affiliation: 1] Department of Physics, University of Fribourg, Fribourg CH1700, Switzerland [2] School of Systems Science, Beijing Normal University, Beijing 100875, PR China.
authors.forename: An
authors.initials: A
authors.lastname: Zeng
authors.affiliation: Department of Physics, University of Fribourg, Fribourg CH1700, Switzerland.
authors.forename: Hao
authors.initials: H
authors.lastname: Liu
authors.affiliation: 1] Web Sciences Center, University of Electronic Science and Technology of China, Chengdu 611731, P.R. China [2] Department of Physics, University of Fribourg, Fribourg CH1700, Switzerland.
authors.forename: Ming-Sheng
authors.initials: MS
authors.lastname: Shang
authors.affiliation: Web Sciences Center, University of Electronic Science and Technology of China, Chengdu 611731, P.R. China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhou