Dynamic Adaptation for WPANs Collision Prevention in eHealth Environments

© 2013 IEEE. This paper presents several adaptive mechanisms to dynamically update the wireless personal area networks (WPANs) parameters that are essential in wearable devices, especially in healthcare environments. Instead of collision detection and recovery, collision prevention is achieved using the proposed algorithms to guarantee a collision-free environment. We present a binary integer programming model for the optimal solution. To avoid the increased complexity, we introduce six suboptimal algorithms. The presented algorithms try to minimize network disruption by updating the parameters of a minimal number of the WPANs. The simulation results show how the algorithms trade off minimal disruption and time complexity

Reputation-based Trust Management in Peer-to-Peer File Sharing Systems

Trust is required in file sharing peer-to-peer (P2P) systems to achieve better cooperation among peers and reduce malicious uploads. In reputation-based P2P systems, reputation is used to build trust among peers based on their past transactions and feedbacks from other peers. In these systems, reputable peers will usually be selected to upload requested files, decreasing significantly malicious uploads in the system. This thesis surveys different reputation management systems with a focus on reputation based P2P systems. We breakdown a typical reputation system into functional components. We discuss each component and present proposed solutions from the literature. Different reputation-based systems are described and analyzed. Each proposed scheme presents a particular perspective in addressing peers’ reputation. This thesis also presents a novel trust management framework and associated schemes for partially decentralized file sharing P2P systems. We address trust according to three identified dimensions: Authentic Behavior, Credibility Behavior and Contribution Behavior. Within our trust management framework, we proposed several algorithms for reputation management. In particular, we proposed algorithms to detect malicious peers that send inauthentic files, and liar peers that send wrong feedbacks. Reputable peers need to be motivated to upload authentic files by increasing the benefits received from the system. In addition, free riders need to contribute positively to the system. These peers are consuming resources without uploading to others. To provide the right incentives for peers, we develop a novel service differentiation scheme based on peers’ contribution rather than peers’ reputation. The proposed scheme protects the system against free-riders and malicious peers and reduces the service provided to them. In this thesis, we also propose a novel recommender framework for partially decentralized file sharing P2P systems. We take advantage from the partial search process used in these systems to explore the relationships between peers. The proposed recommender system does not require any additional effort from the users since implicit rating is used. The recommender system also does not suffer from the problems that affect traditional collaborative filtering schemes like the Cold start, the Data sparseness and the Popularity effect. Over all, our unified approach to trust management and recommendations allows for better system health and increased user satisfaction

Gestion coopérative de la qualité de service dans les applications multimédias : spécification et simulation

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Super-Node Topology In Collaborative Learning: Concrete Examples And Benefits

In the context of education, collaborative learning is one of the pillars of teaching and learning approaches. It has been encouraged for its notable advantages in creating an active learning environment. Incorporating new and effective collaborative learning strategies in teaching would increase students\u27 interest and understanding, boost curiosity and willingness to do better, improve students\u27 interpersonal and leadership skills, increase engagement, and improve the overall learning experience. This paper proposes a supernode-based approach for student groups\u27 formation, a new method inspired by the peer-to-peer topology for file sharing systems. This method can be applied to a variety of courses, including networking and software development courses. Its benefits range from developing students\u27 awareness of each other\u27s academic needs to increasing interactivity and willingness to help each other, optimizing the teaching time, and enhancing the learning outcomes in general

Super-Node Topology for Effective Students’ Advising

Academic advising plays a pivotal role in students’ academic success and progress. Several advising strategies were proposed and used to achieve satisfactory goals. Supernode topologies are known for their efficient use of resources and can be adopted in the provisioning of academic services to leverage their inherent advantages and improve the provisioning process. In previous work, we have applied the supernode topology in collaborative learning. This paper extends this concept to providing and managing university services, focusing on academic advising services. In a fine-grained version of the supernode-based advising service, experienced and skilled students provide extra advising support to their peers. This is referred to as peer-advising, and it brings several advantages, including increased advised students satisfaction, harnessing advising students’ communication and social skills, and reduced faculty advising time

Personalized Recommendations in Peer-to-Peer Systems

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