232 research outputs found
Recommender Systems
The ongoing rapid expansion of the Internet greatly increases the necessity
of effective recommender systems for filtering the abundant information.
Extensive research for recommender systems is conducted by a broad range of
communities including social and computer scientists, physicists, and
interdisciplinary researchers. Despite substantial theoretical and practical
achievements, unification and comparison of different approaches are lacking,
which impedes further advances. In this article, we review recent developments
in recommender systems and discuss the major challenges. We compare and
evaluate available algorithms and examine their roles in the future
developments. In addition to algorithms, physical aspects are described to
illustrate macroscopic behavior of recommender systems. Potential impacts and
future directions are discussed. We emphasize that recommendation has a great
scientific depth and combines diverse research fields which makes it of
interests for physicists as well as interdisciplinary researchers.Comment: 97 pages, 20 figures (To appear in Physics Reports
HypeRS: Building a Hypergraph-driven ensemble Recommender System
Recommender systems are designed to predict user preferences over collections
of items. These systems process users' previous interactions to decide which
items should be ranked higher to satisfy their desires. An ensemble recommender
system can achieve great recommendation performance by effectively combining
the decisions generated by individual models. In this paper, we propose a novel
ensemble recommender system that combines predictions made by different models
into a unified hypergraph ranking framework. This is the first time that
hypergraph ranking has been employed to model an ensemble of recommender
systems. Hypergraphs are generalizations of graphs where multiple vertices can
be connected via hyperedges, efficiently modeling high-order relations. We
differentiate real and predicted connections between users and items by
assigning different hyperedge weights to individual recommender systems. We
perform experiments using four datasets from the fields of movie, music and
news media recommendation. The obtained results show that the ensemble
hypergraph ranking method generates more accurate recommendations compared to
the individual models and a weighted hybrid approach. The assignment of
different hyperedge weights to the ensemble hypergraph further improves the
performance compared to a setting with identical hyperedge weights
Self-Supervised Hypergraph Convolutional Networks for Session-based Recommendation
Session-based recommendation (SBR) focuses on next-item prediction at a
certain time point. As user profiles are generally not available in this
scenario, capturing the user intent lying in the item transitions plays a
pivotal role. Recent graph neural networks (GNNs) based SBR methods regard the
item transitions as pairwise relations, which neglect the complex high-order
information among items. Hypergraph provides a natural way to capture
beyond-pairwise relations, while its potential for SBR has remained unexplored.
In this paper, we fill this gap by modeling session-based data as a hypergraph
and then propose a hypergraph convolutional network to improve SBR. Moreover,
to enhance hypergraph modeling, we devise another graph convolutional network
which is based on the line graph of the hypergraph and then integrate
self-supervised learning into the training of the networks by maximizing mutual
information between the session representations learned via the two networks,
serving as an auxiliary task to improve the recommendation task. Since the two
types of networks both are based on hypergraph, which can be seen as two
channels for hypergraph modeling, we name our model \textbf{DHCN} (Dual Channel
Hypergraph Convolutional Networks). Extensive experiments on three benchmark
datasets demonstrate the superiority of our model over the SOTA methods, and
the results validate the effectiveness of hypergraph modeling and
self-supervised task. The implementation of our model is available at
https://github.com/xiaxin1998/DHCNComment: 9 pages, 4 figures, accepted by AAAI'2
Multiobjective e-commerce recommendations based on hypergraph ranking
© 2018 Recommender systems are emerging in e-commerce as important promotion tools to assist customers to discover potentially interesting items. Currently, most of these are single-objective and search for items that fit the overall preference of a particular user. In real applications, such as restaurant recommendations, however, users often have multiple objectives such as group preferences and restaurant ambiance. This paper highlights the need for multi-objective recommendations and provides a solution using hypergraph ranking. A general User–Item–Attribute–Context data model is proposed to summarize different information resources and high-order relationships for the construction of a multipartite hypergraph. This study develops an improved balanced hypergraph ranking method to rank different types of objects in hypergraph data. An overall framework is then proposed as a guideline for the implementation of multi-objective recommender systems. Empirical experiments are conducted with the dataset from a review site Yelp.com, and the outcomes demonstrate that the proposed model performs very well for multi-objective recommendations. The experiments also demonstrate that this framework is still compatible for traditional single-objective recommendations and can improve accuracy significantly. In conclusion, the proposed multi-objective recommendation framework is able to handle complex and changing demands for e-commerce customers
Recommending on graphs: a comprehensive review from a data perspective
Recent advances in graph-based learning approaches have demonstrated their
effectiveness in modelling users' preferences and items' characteristics for
Recommender Systems (RSS). Most of the data in RSS can be organized into graphs
where various objects (e.g., users, items, and attributes) are explicitly or
implicitly connected and influence each other via various relations. Such a
graph-based organization brings benefits to exploiting potential properties in
graph learning (e.g., random walk and network embedding) techniques to enrich
the representations of the user and item nodes, which is an essential factor
for successful recommendations. In this paper, we provide a comprehensive
survey of Graph Learning-based Recommender Systems (GLRSs). Specifically, we
start from a data-driven perspective to systematically categorize various
graphs in GLRSs and analyze their characteristics. Then, we discuss the
state-of-the-art frameworks with a focus on the graph learning module and how
they address practical recommendation challenges such as scalability, fairness,
diversity, explainability and so on. Finally, we share some potential research
directions in this rapidly growing area.Comment: Accepted by UMUA
A Survey of Graph Neural Networks for Social Recommender Systems
Social recommender systems (SocialRS) simultaneously leverage user-to-item
interactions as well as user-to-user social relations for the task of
generating item recommendations to users. Additionally exploiting social
relations is clearly effective in understanding users' tastes due to the
effects of homophily and social influence. For this reason, SocialRS has
increasingly attracted attention. In particular, with the advance of Graph
Neural Networks (GNN), many GNN-based SocialRS methods have been developed
recently. Therefore, we conduct a comprehensive and systematic review of the
literature on GNN-based SocialRS. In this survey, we first identify 80 papers
on GNN-based SocialRS after annotating 2151 papers by following the PRISMA
framework (Preferred Reporting Items for Systematic Reviews and Meta-Analysis).
Then, we comprehensively review them in terms of their inputs and architectures
to propose a novel taxonomy: (1) input taxonomy includes 5 groups of input type
notations and 7 groups of input representation notations; (2) architecture
taxonomy includes 8 groups of GNN encoder, 2 groups of decoder, and 12 groups
of loss function notations. We classify the GNN-based SocialRS methods into
several categories as per the taxonomy and describe their details. Furthermore,
we summarize the benchmark datasets and metrics widely used to evaluate the
GNN-based SocialRS methods. Finally, we conclude this survey by presenting some
future research directions.Comment: GitHub repository with the curated list of papers:
https://github.com/claws-lab/awesome-GNN-social-recsy
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