747 research outputs found
Attentive Aspect Modeling for Review-aware Recommendation
In recent years, many studies extract aspects from user reviews and integrate
them with ratings for improving the recommendation performance. The common
aspects mentioned in a user's reviews and a product's reviews indicate indirect
connections between the user and product. However, these aspect-based methods
suffer from two problems. First, the common aspects are usually very sparse,
which is caused by the sparsity of user-product interactions and the diversity
of individual users' vocabularies. Second, a user's interests on aspects could
be different with respect to different products, which are usually assumed to
be static in existing methods. In this paper, we propose an Attentive
Aspect-based Recommendation Model (AARM) to tackle these challenges. For the
first problem, to enrich the aspect connections between user and product,
besides common aspects, AARM also models the interactions between synonymous
and similar aspects. For the second problem, a neural attention network which
simultaneously considers user, product and aspect information is constructed to
capture a user's attention towards aspects when examining different products.
Extensive quantitative and qualitative experiments show that AARM can
effectively alleviate the two aforementioned problems and significantly
outperforms several state-of-the-art recommendation methods on top-N
recommendation task.Comment: Camera-ready manuscript for TOI
Towards Question-based Recommender Systems
Conversational and question-based recommender systems have gained increasing
attention in recent years, with users enabled to converse with the system and
better control recommendations. Nevertheless, research in the field is still
limited, compared to traditional recommender systems. In this work, we propose
a novel Question-based recommendation method, Qrec, to assist users to find
items interactively, by answering automatically constructed and algorithmically
chosen questions. Previous conversational recommender systems ask users to
express their preferences over items or item facets. Our model, instead, asks
users to express their preferences over descriptive item features. The model is
first trained offline by a novel matrix factorization algorithm, and then
iteratively updates the user and item latent factors online by a closed-form
solution based on the user answers. Meanwhile, our model infers the underlying
user belief and preferences over items to learn an optimal question-asking
strategy by using Generalized Binary Search, so as to ask a sequence of
questions to the user. Our experimental results demonstrate that our proposed
matrix factorization model outperforms the traditional Probabilistic Matrix
Factorization model. Further, our proposed Qrec model can greatly improve the
performance of state-of-the-art baselines, and it is also effective in the case
of cold-start user and item recommendations.Comment: accepted by SIGIR 202
Negative Link Prediction in Social Media
Signed network analysis has attracted increasing attention in recent years.
This is in part because research on signed network analysis suggests that
negative links have added value in the analytical process. A major impediment
in their effective use is that most social media sites do not enable users to
specify them explicitly. In other words, a gap exists between the importance of
negative links and their availability in real data sets. Therefore, it is
natural to explore whether one can predict negative links automatically from
the commonly available social network data. In this paper, we investigate the
novel problem of negative link prediction with only positive links and
content-centric interactions in social media. We make a number of important
observations about negative links, and propose a principled framework NeLP,
which can exploit positive links and content-centric interactions to predict
negative links. Our experimental results on real-world social networks
demonstrate that the proposed NeLP framework can accurately predict negative
links with positive links and content-centric interactions. Our detailed
experiments also illustrate the relative importance of various factors to the
effectiveness of the proposed framework
RECOMED: A Comprehensive Pharmaceutical Recommendation System
A comprehensive pharmaceutical recommendation system was designed based on
the patients and drugs features extracted from Drugs.com and Druglib.com.
First, data from these databases were combined, and a dataset of patients and
drug information was built. Secondly, the patients and drugs were clustered,
and then the recommendation was performed using different ratings provided by
patients, and importantly by the knowledge obtained from patients and drug
specifications, and considering drug interactions. To the best of our
knowledge, we are the first group to consider patients conditions and history
in the proposed approach for selecting a specific medicine appropriate for that
particular user. Our approach applies artificial intelligence (AI) models for
the implementation. Sentiment analysis using natural language processing
approaches is employed in pre-processing along with neural network-based
methods and recommender system algorithms for modeling the system. In our work,
patients conditions and drugs features are used for making two models based on
matrix factorization. Then we used drug interaction to filter drugs with severe
or mild interactions with other drugs. We developed a deep learning model for
recommending drugs by using data from 2304 patients as a training set, and then
we used data from 660 patients as our validation set. After that, we used
knowledge from critical information about drugs and combined the outcome of the
model into a knowledge-based system with the rules obtained from constraints on
taking medicine.Comment: 39 pages, 14 figures, 13 table
Personalized Expert Recommendation: Models and Algorithms
Many large-scale information sharing systems including social media systems, questionanswering
sites and rating and reviewing applications have been growing rapidly, allowing
millions of human participants to generate and consume information on an unprecedented
scale. To manage the sheer growth of information generation, there comes the need to enable
personalization of information resources for users — to surface high-quality content
and feeds, to provide personally relevant suggestions, and so on. A fundamental task in
creating and supporting user-centered personalization systems is to build rich user profile
to aid recommendation for better user experience.
Therefore, in this dissertation research, we propose models and algorithms to facilitate
the creation of new crowd-powered personalized information sharing systems. Specifically,
we first give a principled framework to enable personalization of resources so that
information seekers can be matched with customized knowledgeable users based on their
previous historical actions and contextual information; We then focus on creating rich
user models that allows accurate and comprehensive modeling of user profiles for long
tail users, including discovering user’s known-for profile, user’s opinion bias and user’s
geo-topic profile. In particular, this dissertation research makes two unique contributions:
First, we introduce the problem of personalized expert recommendation and propose
the first principled framework for addressing this problem. To overcome the sparsity issue,
we investigate the use of user’s contextual information that can be exploited to build robust
models of personal expertise, study how spatial preference for personally-valuable expertise
varies across regions, across topics and based on different underlying social communities,
and integrate these different forms of preferences into a matrix factorization-based
personalized expert recommender.
Second, to support the personalized recommendation on experts, we focus on modeling
and inferring user profiles in online information sharing systems. In order to tap
the knowledge of most majority of users, we provide frameworks and algorithms to accurately
and comprehensively create user models by discovering user’s known-for profile,
user’s opinion bias and user’s geo-topic profile, with each described shortly as follows:
—We develop a probabilistic model called Bayesian Contextual Poisson Factorization
to discover what users are known for by others. Our model considers as input a small fraction
of users whose known-for profiles are already known and the vast majority of users for
whom we have little (or no) information, learns the implicit relationships between user?s
known-for profiles and their contextual signals, and finally predict known-for profiles for
those majority of users.
—We explore user’s topic-sensitive opinion bias, propose a lightweight semi-supervised
system called “BiasWatch” to semi-automatically infer the opinion bias of long-tail users,
and demonstrate how user’s opinion bias can be exploited to recommend other users with
similar opinion in social networks.
— We study how a user’s topical profile varies geo-spatially and how we can model
a user’s geo-spatial known-for profile as the last step in our dissertation for creation of
rich user profile. We propose a multi-layered Bayesian hierarchical user factorization to
overcome user heterogeneity and an enhanced model to alleviate the sparsity issue by integrating
user contexts into the two-layered hierarchical user model for better representation
of user’s geo-topic preference by others
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