A survey of transfer learning for collaborative recommendation with auxiliary data
Introduction
Intelligent recommendation technology [1], [4], [18], [31], [45], [48] has been a standard component embedded in many Internet systems such as e-commerce and advertisement systems to provide personalized services. There are two main approaches widely used in personalized recommendation for an active user, i.e., content-based recommendation [3] and collaborative recommendation [14]. Content-based methods promote an item based on the relevance between a candidate item and the active user׳s consumed items, while collaborative recommendation techniques focus on collective intelligence and exploit the community׳s data so as to recommend preferred items from users with similar tastes. However, both methods are limited to users׳ feedbacks of explicit scores or implicit examinations, which may result in a challenging problem, data sparsity, due to the lack of users׳ behaviors.
Fortunately, there are often some additionally available data besides the users׳ feedbacks (e.g., numerical ratings) in a recommender system. There are at least four types of auxiliary data as shown in Table 1, such as content information [52], [56], time contextual information [23], [36], social or information networks [21], [49], [54] and additional feedbacks [19], [29], [39]. These auxiliary data have the potential to help relieve the aforementioned sparsity problem and thus improve the recommendation performance. In this survey, we study on how to exploit different types of auxiliary data in collaborative recommendation, which is coined as collaborative recommendation with auxiliary data (CRAD).
Specifically, we study the CRAD problem from an inductive transfer learning [37] view (instead of unsupervised or transductive transfer learning views [2]), in which we consider the users׳ feedback data as our target data or supervised information, and all the other additional information as our auxiliary data. In particular, we focus on how to enable knowledge transfer from some auxiliary data to the target data in order to address the aforementioned sparsity challenge. We discuss some representative transfer learning techniques, aiming to answer the fundamental question of transfer learning [37], i.e., “how to transfer”. With this focus in our survey, we extend previous categorization of transfer learning techniques in collaborative filtering [38], [43], and answer the above question from two dimensions, including knowledge transfer algorithm styles (i.e., adaptive, collective and integrative knowledge transfer) and knowledge transfer strategies (i.e., prediction rule, regularization and constraint). Then, we propose a novel and generic knowledge transfer framework and describe some representative works in each category to answer the “how to transfer” question in detail, in particular the main idea that may be generalized to other applications. Finally, we conclude the survey with some summarized discussions and several exciting future directions.
Section snippets
Problem definition
We have a target data set and an auxiliary data set. In the target data set, we have some feedbacks from n users and m items, which is usually represented as a rating matrix and an indicator matrix , where means that the feedback rui is observed. In the auxiliary data set, we have some additional data such as content, context, network and feedback information as shown in Table 1. Our goal is to predict the unobserved feedbacks in R by transferring knowledge from the
Adaptive knowledge transfer
Adaptive knowledge transfer aims to adapt the knowledge extracted from an auxiliary data domain to a target data domain. This is a directed knowledge transfer approach similar to traditional domain adaptation methods. In this section, we describe two adaptive knowledge transfer strategies as instantiated from Eq. (1), including (i) transfer via regularization, , and (ii) transfer via constraint, .
Collective knowledge transfer
Collective knowledge transfer usually jointly learns the shared knowledge and unshared effect of the target data and the auxiliary data simultaneously, which is a bi-directed knowledge transfer approach with richer interactions similar to multi-task learning algorithms. We describe some representative works of collective knowledge transfer via constraint on model parameters, , which is also an instantiation of Eq. (1). Note that the model parameter Θ and
Integrative knowledge transfer
Integrative knowledge transfer incorporates the raw auxiliary data as known knowledge into the learning task on the target data. It can be considered as an embedded knowledge transfer approach similar to feature engineering, information fusion and data integration methods. Mathematically speaking, we can instantiate the generic framework in Eq. (1), and have (i) transfer via prediction rule, , (ii) transfer via regularization, , and (iii) transfer via
Discussions
We summarize some representative works of transfer learning for collaborative recommendation with auxiliary data (TL-CRAD) in Table 2. We can see that integrative knowledge transfer via prediction rule and collective knowledge transfer via constraint have recently received more attention, which are also the state-of-the-art TL-CRAD algorithms w.r.t. recommendation accuracy in corresponding problem settings. The interaction between auxiliary data and target data usually becomes richer from
Acknowledgment
I would like to thank Prof. Qiang Yang for advice and comments, Dr. Bin Li for linguistic improvement and helpful discussions, the editors and reviewers for constructive suggestions, and the support of Natural Science Foundation of Guangdong Province No. 2014A030310268, National Natural Science Foundation of China Nos. 61502307, 61170077, 61472258 and Natural Science Foundation of SZU No. 201436.
Weike Pan received the Ph.D. degree in Computer Science and Engineering from the Hong Kong University of Science and Technology, Kowloon, Hong Kong, China, in 2012. He is currently a Lecturer (research oriented) with the College of Computer Science and Software Engineering, Shenzhen University, Shenzhen, China. His research interests include transfer learning, recommender systems, and statistical machine learning.
References (61)
- et al.
Recommender systems survey
Knowl.-Based Syst.
(2013) - et al.
Robust probabilistic tensor analysis for time-variant collaborative filtering
Neurocomputing
(2013) - et al.
Compressed knowledge transfer via factorization machine for heterogeneous collaborative recommendation
Knowl.-Based Syst.
(2015) - et al.
Adaptive bayesian personalized ranking for heterogeneous implicit feedbacks
Knowl.-Based Syst.
(2015) - et al.
A literature review and classification of recommender systems research
Expert Syst. Appl.
(2012) - et al.
A survey of collaborative filtering based social recommender systems
Comput. Commun.
(2014) - et al.
A random-walk based recommendation algorithm considering item categories
Neurocomputing
(2013) - et al.
Collaborative filtering with social regularization for tv program recommendation
Knowl.-Based Syst.
(2013) - et al.
Toward the next generation of recommender systemsa survey of the state-of-the-art and possible extensions
IEEE Trans. Knowl. Data Eng.
(2005) - Andrew Arnold, Ramesh Nallapati, William W. Cohen, A comparative study of methods for transductive transfer learning,...
Convex Optimization
Analysis and detection of fake views in online video services
ACM Trans. Multimed. Comput. Commun. Appl.
Smart streaming for online video services
IEEE Trans. Multimed.
Svdfeaturea toolkit for feature-based collaborative filtering
J. Mach. Learn. Res.
Using collaborative filtering to weave an information tapestry
Commun. ACM
Recommender Systems: An Introduction
Modeling user preferences in recommender systemsa classification framework for explicit and implicit user feedback
ACM Trans. Interact. Intell. Syst.
Social recommendation with cross-domain transferable knowledge
IEEE Trans. Knowl. Data Eng.
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Weike Pan received the Ph.D. degree in Computer Science and Engineering from the Hong Kong University of Science and Technology, Kowloon, Hong Kong, China, in 2012. He is currently a Lecturer (research oriented) with the College of Computer Science and Software Engineering, Shenzhen University, Shenzhen, China. His research interests include transfer learning, recommender systems, and statistical machine learning.