14,146 research outputs found
Trust-Networks in Recommender Systems
Similarity-based recommender systems suffer from significant limitations, such as data sparseness and scalability. The goal of this research is to improve recommender systems by incorporating the social concepts of trust and reputation. By introducing a trust model we can improve the quality and accuracy of the recommended items. Three trust-based recommendation strategies are presented and evaluated against the popular MovieLens [8] dataset
COMMUNITY DETECTION AND INFLUENCE MAXIMIZATION IN ONLINE SOCIAL NETWORKS
The detecting and clustering of data and users into communities on the social web are important and complex issues in order to develop smart marketing models in changing and evolving social ecosystems. These marketing models are created by individual decision to purchase a product and are influenced by friends and acquaintances. This leads to novel marketing models, which view users as members of online social network communities, rather than the traditional view of marketing to individuals. This thesis starts by examining models that detect communities in online social networks. Then an enhanced approach to detect community which clusters similar nodes together is suggested. Social relationships play an important role in determining user behavior. For example, a user might purchase a product that his/her friend recently bought. Such a phenomenon is called social influence and is used to study how far the action of one user can affect the behaviors of others. Then an original metric used to compute the influential power of social network users based on logs of common actions in order to infer a probabilistic influence propagation model. Finally, a combined community detection algorithm and suggested influence propagation approach reveals a new influence maximization model by identifying and using the most influential users within their communities. In doing so, we employed a fuzzy logic based technique to determine the key users who drive this influence in their communities and diffuse a certain behavior. This original approach contrasts with previous influence propagation models, which did not use similarity opportunities among members of communities to maximize influence propagation. The performance results show that the model activates a higher number of overall nodes in contemporary social networks, starting from a smaller set of key users, as compared to existing landmark approaches which influence fewer nodes, yet employ a larger set of key users
Challenging Social Media Threats using Collective Well-being Aware Recommendation Algorithms and an Educational Virtual Companion
Social media (SM) have become an integral part of our lives, expanding our
inter-linking capabilities to new levels. There is plenty to be said about
their positive effects. On the other hand however, some serious negative
implications of SM have repeatedly been highlighted in recent years, pointing
at various SM threats for society, and its teenagers in particular: from common
issues (e.g. digital addiction and polarization) and manipulative influences of
algorithms to teenager-specific issues (e.g. body stereotyping). The full
impact of current SM platform design -- both at an individual and societal
level -- asks for a comprehensive evaluation and conceptual improvement. We
extend measures of Collective Well-Being (CWB) to SM communities. As users'
relationships and interactions are a central component of CWB, education is
crucial to improve CWB. We thus propose a framework based on an adaptive
"social media virtual companion" for educating and supporting the entire
students' community to interact with SM. The virtual companion will be powered
by a Recommender System (CWB-RS) that will optimize a CWB metric instead of
engagement or platform profit, which currently largely drives recommender
systems thereby disregarding any societal collateral effect. CWB-RS will
optimize CWB both in the short term, by balancing the level of SM threat the
students are exposed to, as well as in the long term, by adopting an
Intelligent Tutor System role and enabling adaptive and personalized sequencing
of playful learning activities. This framework offers an initial step on
understanding how to design SM systems and embedded educational interventions
that favor a more healthy and positive society
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