6,403 research outputs found
Attributes Coupling based Item Enhanced Matrix Factorization Technique for Recommender Systems
Recommender system has attracted lots of attentions since it helps users
alleviate the information overload problem. Matrix factorization technique is
one of the most widely employed collaborative filtering techniques in the
research of recommender systems due to its effectiveness and efficiency in
dealing with very large user-item rating matrices. Recently, based on the
intuition that additional information provides useful insights for matrix
factorization techniques, several recommendation algorithms have utilized
additional information to improve the performance of matrix factorization
methods. However, the majority focus on dealing with the cold start user
problem and ignore the cold start item problem. In addition, there are few
suitable similarity measures for these content enhanced matrix factorization
approaches to compute the similarity between categorical items. In this paper,
we propose attributes coupling based item enhanced matrix factorization method
by incorporating item attribute information into matrix factorization technique
as well as adapting the coupled object similarity to capture the relationship
between items. Item attribute information is formed as an item relationship
regularization term to regularize the process of matrix factorization.
Specifically, the similarity between items is measured by the Coupled Object
Similarity considering coupling between items. Experimental results on two real
data sets show that our proposed method outperforms state-of-the-art
recommendation algorithms and can effectively cope with the cold start item
problem when more item attribute information is available.Comment: 15 page
Parallel and Distributed Collaborative Filtering: A Survey
Collaborative filtering is amongst the most preferred techniques when
implementing recommender systems. Recently, great interest has turned towards
parallel and distributed implementations of collaborative filtering algorithms.
This work is a survey of the parallel and distributed collaborative filtering
implementations, aiming not only to provide a comprehensive presentation of the
field's development, but also to offer future research orientation by
highlighting the issues that need to be further developed.Comment: 46 page
Matrix Factorization with Explicit Trust and Distrust Relationships
With the advent of online social networks, recommender systems have became
crucial for the success of many online applications/services due to their
significance role in tailoring these applications to user-specific needs or
preferences. Despite their increasing popularity, in general recommender
systems suffer from the data sparsity and the cold-start problems. To alleviate
these issues, in recent years there has been an upsurge of interest in
exploiting social information such as trust relations among users along with
the rating data to improve the performance of recommender systems. The main
motivation for exploiting trust information in recommendation process stems
from the observation that the ideas we are exposed to and the choices we make
are significantly influenced by our social context. However, in large user
communities, in addition to trust relations, the distrust relations also exist
between users. For instance, in Epinions the concepts of personal "web of
trust" and personal "block list" allow users to categorize their friends based
on the quality of reviews into trusted and distrusted friends, respectively. In
this paper, we propose a matrix factorization based model for recommendation in
social rating networks that properly incorporates both trust and distrust
relationships aiming to improve the quality of recommendations and mitigate the
data sparsity and the cold-start users issues. Through experiments on the
Epinions data set, we show that our new algorithm outperforms its standard
trust-enhanced or distrust-enhanced counterparts with respect to accuracy,
thereby demonstrating the positive effect that incorporation of explicit
distrust information can have on recommender systems.Comment: ACM Transactions on Information System
Quantifying Long Range Dependence in Language and User Behavior to improve RNNs
Characterizing temporal dependence patterns is a critical step in
understanding the statistical properties of sequential data. Long Range
Dependence (LRD) --- referring to long-range correlations decaying as a power
law rather than exponentially w.r.t. distance --- demands a different set of
tools for modeling the underlying dynamics of the sequential data. While it has
been widely conjectured that LRD is present in language modeling and sequential
recommendation, the amount of LRD in the corresponding sequential datasets has
not yet been quantified in a scalable and model-independent manner. We propose
a principled estimation procedure of LRD in sequential datasets based on
established LRD theory for real-valued time series and apply it to sequences of
symbols with million-item-scale dictionaries. In our measurements, the
procedure estimates reliably the LRD in the behavior of users as they write
Wikipedia articles and as they interact with YouTube. We further show that
measuring LRD better informs modeling decisions in particular for RNNs whose
ability to capture LRD is still an active area of research. The quantitative
measure informs new Evolutive Recurrent Neural Networks (EvolutiveRNNs)
designs, leading to state-of-the-art results on language understanding and
sequential recommendation tasks at a fraction of the computational cost
Collaborative filtering via sparse Markov random fields
Recommender systems play a central role in providing individualized access to
information and services. This paper focuses on collaborative filtering, an
approach that exploits the shared structure among mind-liked users and similar
items. In particular, we focus on a formal probabilistic framework known as
Markov random fields (MRF). We address the open problem of structure learning
and introduce a sparsity-inducing algorithm to automatically estimate the
interaction structures between users and between items. Item-item and user-user
correlation networks are obtained as a by-product. Large-scale experiments on
movie recommendation and date matching datasets demonstrate the power of the
proposed method
Hierarchical Temporal Convolutional Networks for Dynamic Recommender Systems
Recommender systems that can learn from cross-session data to dynamically
predict the next item a user will choose are crucial for online platforms.
However, existing approaches often use out-of-the-box sequence models which are
limited by speed and memory consumption, are often infeasible for production
environments, and usually do not incorporate cross-session information, which
is crucial for effective recommendations. Here we propose Hierarchical Temporal
Convolutional Networks (HierTCN), a hierarchical deep learning architecture
that makes dynamic recommendations based on users' sequential multi-session
interactions with items. HierTCN is designed for web-scale systems with
billions of items and hundreds of millions of users. It consists of two levels
of models: The high-level model uses Recurrent Neural Networks (RNN) to
aggregate users' evolving long-term interests across different sessions, while
the low-level model is implemented with Temporal Convolutional Networks (TCN),
utilizing both the long-term interests and the short-term interactions within
sessions to predict the next interaction. We conduct extensive experiments on a
public XING dataset and a large-scale Pinterest dataset that contains 6 million
users with 1.6 billion interactions. We show that HierTCN is 2.5x faster than
RNN-based models and uses 90% less data memory compared to TCN-based models. We
further develop an effective data caching scheme and a queue-based mini-batch
generator, enabling our model to be trained within 24 hours on a single GPU.
Our model consistently outperforms state-of-the-art dynamic recommendation
methods, with up to 18% improvement in recall and 10% in mean reciprocal rank.Comment: Accepted by the Web Conference 2019 (WWW 2019) as a full pape
Contextual Hybrid Session-based News Recommendation with Recurrent Neural Networks
Recommender systems help users deal with information overload by providing
tailored item suggestions to them. The recommendation of news is often
considered to be challenging, since the relevance of an article for a user can
depend on a variety of factors, including the user's short-term reading
interests, the reader's context, or the recency or popularity of an article.
Previous work has shown that the use of Recurrent Neural Networks is promising
for the next-in-session prediction task, but has certain limitations when only
recorded item click sequences are used as input. In this work, we present a
contextual hybrid, deep learning based approach for session-based news
recommendation that is able to leverage a variety of information types. We
evaluated our approach on two public datasets, using a temporal evaluation
protocol that simulates the dynamics of a news portal in a realistic way. Our
results confirm the benefits of considering additional types of information,
including article popularity and recency, in the proposed way, resulting in
significantly higher recommendation accuracy and catalog coverage than other
session-based algorithms. Additional experiments show that the proposed
parameterizable loss function used in our method also allows us to balance two
usually conflicting quality factors, accuracy and novelty.
Keywords: Artificial Neural Networks, Context-Aware Recommender Systems,
Hybrid Recommender Systems, News Recommender Systems, Session-based
RecommendationComment: 20 pgs. Published at IEEE Access, Volume 7, 2019.
https://ieeexplore.ieee.org/document/890868
A Review on Recommendation Systems: Context-aware to Social-based
The number of Internet users had grown rapidly enticing companies and
cooperations to make full use of recommendation infrastructures. Consequently,
online advertisement companies emerged to aid us in the presence of numerous
items and users. Even as a user, you may find yourself drowned in a set of
items that you think you might need, but you are not sure if you should try
them. Those items could be online services, products, places or even a person
for a friendship. Therefore, we need recommender systems that pave the way and
help us making good decisions. This paper provides a review on traditional
recommendation systems, recommendation system evaluations and metrics,
context-aware recommendation systems, and social-based recommendation systems.
While it is hard to include all the information in a brief review paper, we try
to have an introductory review over the essentials of recommendation systems.
More detailed information on each chapter will be found in the corresponding
references. For the purpose of explaining the concept in a different way, we
provided slides available on
https://www.slideshare.net/MahdiSeyednejad/recommender-systems-97094937.Comment: 44 pages without bibliography, 4 chapters, Slide presentation:
https://www.slideshare.net/MahdiSeyednejad/recommender-systems-9709493
An Analysis of Approaches Taken in the ACM RecSys Challenge 2018 for Automatic Music Playlist Continuation
The ACM Recommender Systems Challenge 2018 focused on the task of automatic
music playlist continuation, which is a form of the more general task of
sequential recommendation. Given a playlist of arbitrary length with some
additional meta-data, the task was to recommend up to 500 tracks that fit the
target characteristics of the original playlist. For the RecSys Challenge,
Spotify released a dataset of one million user-generated playlists.
Participants could compete in two tracks, i.e., main and creative tracks.
Participants in the main track were only allowed to use the provided training
set, however, in the creative track, the use of external public sources was
permitted. In total, 113 teams submitted 1,228 runs to the main track; 33 teams
submitted 239 runs to the creative track. The highest performing team in the
main track achieved an R-precision of 0.2241, an NDCG of 0.3946, and an average
number of recommended songs clicks of 1.784. In the creative track, an
R-precision of 0.2233, an NDCG of 0.3939, and a click rate of 1.785 was
obtained by the best team. This article provides an overview of the challenge,
including motivation, task definition, dataset description, and evaluation. We
further report and analyze the results obtained by the top performing teams in
each track and explore the approaches taken by the winners. We finally
summarize our key findings, discuss generalizability of approaches and results
to domains other than music, and list the open avenues and possible future
directions in the area of automatic playlist continuation
Evaluating Prerequisite Qualities for Learning End-to-End Dialog Systems
A long-term goal of machine learning is to build intelligent conversational
agents. One recent popular approach is to train end-to-end models on a large
amount of real dialog transcripts between humans (Sordoni et al., 2015; Vinyals
& Le, 2015; Shang et al., 2015). However, this approach leaves many questions
unanswered as an understanding of the precise successes and shortcomings of
each model is hard to assess. A contrasting recent proposal are the bAbI tasks
(Weston et al., 2015b) which are synthetic data that measure the ability of
learning machines at various reasoning tasks over toy language. Unfortunately,
those tests are very small and hence may encourage methods that do not scale.
In this work, we propose a suite of new tasks of a much larger scale that
attempt to bridge the gap between the two regimes. Choosing the domain of
movies, we provide tasks that test the ability of models to answer factual
questions (utilizing OMDB), provide personalization (utilizing MovieLens),
carry short conversations about the two, and finally to perform on natural
dialogs from Reddit. We provide a dataset covering 75k movie entities and with
3.5M training examples. We present results of various models on these tasks,
and evaluate their performance
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