145 research outputs found
Attack Detection Using Item Vector Shift in Matrix Factorisation Recommenders
This paper proposes a novel method for detecting shilling attacks in Matrix
Factorization (MF)-based Recommender Systems (RS), in which attackers use false
user-item feedback to promote a specific item. Unlike existing methods that use
either use supervised learning to distinguish between attack and genuine
profiles or analyse target item rating distributions to detect false ratings,
our method uses an unsupervised technique to detect false ratings by examining
shifts in item preference vectors that exploit rating deviations and user
characteristics, making it a promising new direction. The experimental results
demonstrate the effectiveness of our approach in various attack scenarios,
including those involving obfuscation techniques
How Fraudster Detection Contributes to Robust Recommendation
The adversarial robustness of recommendation systems under node injection
attacks has received considerable research attention. Recently, a robust
recommendation system GraphRfi was proposed, and it was shown that GraphRfi
could successfully mitigate the effects of injected fake users in the system.
Unfortunately, we demonstrate that GraphRfi is still vulnerable to attacks due
to the supervised nature of its fraudster detection component. Specifically, we
propose a new attack metaC against GraphRfi, and further analyze why GraphRfi
fails under such an attack. Based on the insights we obtained from the
vulnerability analysis, we build a new robust recommendation system PDR by
re-designing the fraudster detection component. Comprehensive experiments show
that our defense approach outperforms other benchmark methods under attacks.
Overall, our research demonstrates an effective framework of integrating
fraudster detection into recommendation to achieve adversarial robustness
Robust Recommender System: A Survey and Future Directions
With the rapid growth of information, recommender systems have become
integral for providing personalized suggestions and overcoming information
overload. However, their practical deployment often encounters "dirty" data,
where noise or malicious information can lead to abnormal recommendations.
Research on improving recommender systems' robustness against such dirty data
has thus gained significant attention. This survey provides a comprehensive
review of recent work on recommender systems' robustness. We first present a
taxonomy to organize current techniques for withstanding malicious attacks and
natural noise. We then explore state-of-the-art methods in each category,
including fraudster detection, adversarial training, certifiable robust
training against malicious attacks, and regularization, purification,
self-supervised learning against natural noise. Additionally, we summarize
evaluation metrics and common datasets used to assess robustness. We discuss
robustness across varying recommendation scenarios and its interplay with other
properties like accuracy, interpretability, privacy, and fairness. Finally, we
delve into open issues and future research directions in this emerging field.
Our goal is to equip readers with a holistic understanding of robust
recommender systems and spotlight pathways for future research and development
A survey of recommender systems for energy efficiency in buildings: Principles, challenges and prospects
Recommender systems have significantly developed in recent years in parallel
with the witnessed advancements in both internet of things (IoT) and artificial
intelligence (AI) technologies. Accordingly, as a consequence of IoT and AI,
multiple forms of data are incorporated in these systems, e.g. social,
implicit, local and personal information, which can help in improving
recommender systems' performance and widen their applicability to traverse
different disciplines. On the other side, energy efficiency in the building
sector is becoming a hot research topic, in which recommender systems play a
major role by promoting energy saving behavior and reducing carbon emissions.
However, the deployment of the recommendation frameworks in buildings still
needs more investigations to identify the current challenges and issues, where
their solutions are the keys to enable the pervasiveness of research findings,
and therefore, ensure a large-scale adoption of this technology. Accordingly,
this paper presents, to the best of the authors' knowledge, the first timely
and comprehensive reference for energy-efficiency recommendation systems
through (i) surveying existing recommender systems for energy saving in
buildings; (ii) discussing their evolution; (iii) providing an original
taxonomy of these systems based on specified criteria, including the nature of
the recommender engine, its objective, computing platforms, evaluation metrics
and incentive measures; and (iv) conducting an in-depth, critical analysis to
identify their limitations and unsolved issues. The derived challenges and
areas of future implementation could effectively guide the energy research
community to improve the energy-efficiency in buildings and reduce the cost of
developed recommender systems-based solutions.Comment: 35 pages, 11 figures, 1 tabl
Reminder Care System: An Activity-Aware Cross-Device Recommendation System
© 2019, Springer Nature Switzerland AG. Alzheimer’s disease (AD) affects large numbers of elderly people worldwide and represents a significant social and economic burden on society, particularly in relation to the need for long term care facilities. These costs can be reduced by enabling people with AD to live independently at home for a longer time. The use of recommendation systems for the Internet of Things (IoT) in the context of smart homes can contribute to this goal. In this paper, we present the Reminder Care System (RCS), a research prototype of a recommendation system for the IoT for elderly people with cognitive disabilities. RCS exploits daily activities that are captured and learned from IoT devices to provide personalised recommendations. The experimental results indicate that RCS can inform the development of real-world IoT applications
Contributions to outlier detection and recommendation systems
Le forage de données, appelé également "Découverte de connaissance dans les bases de données" , est un jeune domaine de recherche interdisciplinaire. Le forage de données étudie les processus d'analyse de grands ensembles de données pour en extraire des connaissances, et les processus de transformation de ces connaissances en des structures faciles à comprendre et à utiliser par les humains. Cette thèse étudie deux tâches importantes dans le domaine du forage de données : la détection des anomalies et la recommandation de produits. La détection des anomalies est l'identification des données non conformes aux observations normales. La recommandation de produit est la prédiction du niveau d'intérêt d'un client pour des produits en se basant sur des données d'achats antérieurs et des données socio-économiques. Plus précisément, cette thèse porte sur 1) la détection des anomalies dans de grands ensembles de données de type catégorielles; et 2) les techniques de recommandation à partir des données de classements asymétriques. La détection des anomalies dans des données catégorielles de grande échelle est un problème important qui est loin d'être résolu. Les méthodes existantes dans ce domaine souffrnt d'une faible efficience et efficacité en raison de la dimensionnalité élevée des données, de la grande taille des bases de données, de la complexité élevée des tests statistiques, ainsi que des mesures de proximité non adéquates. Cette thèse propose une définition formelle d'anomalie dans les données catégorielles ainsi que deux algorithmes efficaces et efficients pour la détection des anomalies dans les données de grande taille. Ces algorithmes ont besoin d'un seul paramètre : le nombre des anomalies. Pour déterminer la valeur de ce paramètre, nous avons développé un critère en nous basant sur un nouveau concept qui est l'holo-entropie. Plusieurs recherches antérieures sur les systèmes de recommandation ont négligé un type de classements répandu dans les applications Web, telles que le commerce électronique (ex. Amazon, Taobao) et les sites fournisseurs de contenu (ex. YouTube). Les données de classements recueillies par ces sites se différencient de celles de classements des films et des musiques par leur distribution asymétrique élevée. Cette thèse propose un cadre mieux adapté pour estimer les classements et les préférences quantitatives d'ordre supérieur pour des données de classements asymétriques. Ce cadre permet de créer de nouveaux modèles de recommandation en se basant sur la factorisation de matrice ou sur l'estimation de voisinage. Des résultats expérimentaux sur des ensembles de données asymétriques indiquent que les modèles créés avec ce cadre ont une meilleure performance que les modèles conventionnels non seulement pour la prédiction de classements, mais aussi pour la prédiction de la liste des Top-N produits
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