Barolli, A.; Loia, V.; Oda, T.; Barolli, L.; Xhafa, F.; Takizawa, M. Computer standards & interfaces Vol. 44, p. 150-158 DOI: 10.1016/j.csi.2015.04.003 Data de publicació: 2016-02-01 Article en revista
In this paper, we present the interface and data visualization of a simulation system for Wireless Mesh Networks (WMNs), which is based on Genetic Algorithms (GAs). We call this system WMN-GA. As evaluation parameters, we consider Packet Delivery Ratio (PDR), throughput and delay metrics. For simulations, we used ns-3 simulator and Hybrid Wireless Mesh Protocol (HWMP). From simulation results, we found that PDR for Weibull distribution is higher than Exponential distribution. But, the throughput of Exponential distribution is higher than Weibull distribution. The delay of Exponential distribution is smaller than Weibull distribution.
This is a copy of the author 's final draft version of an article published in the journal Computer standards & interfaces.
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Trustworthiness and technological security solutions are closely related to online collaborative learning and they can be combined with the aim of reaching information security requirements for e-Learning participants and designers. Moreover, mobile collaborative learning is an emerging educational model devoted to providing the learner with the ability to assimilate learning any time and anywhere. In this paper, we justify the need of trustworthiness models as a functional requirement devoted to improving information security. To this end, we propose a methodological approach to modelling trustworthiness in online collaborative learning. Our proposal sets out to build a theoretical approach with the aim to provide e-Learning designers and managers with guidelines for incorporating security into mobile online collaborative activities through trustworthiness assessment and prediction.
We present the deficiencies of traditional identity-based authorization models in structured Peer-to-Peer (P2P) networks where users' Public Key Certificates (PKCs) represent two roles, authentication and authorization, and the access to the network resources is controlled by Access Control Lists (ACLs). With these deficiencies in mind, we propose a complete new framework for authorization in structured P2P networks based on Attribute Certificates (ACs) and a fully distributed certificate revocation system. We argue that the proposed framework yields a more flexible and secure authorization scheme for structured P2P networks while improving the efficiency of the assignment of privileges.
Recommendation systems and content filtering approaches based on annotations and ratings, essentially rely on users expressing their preferences and interests through their actions, in order to provide personalised content. This activity, in which users engage collectively has been named social tagging, and it is one of the most popular in which users engage online, and although it has opened new possibilities for application interoperability on the semantic web, it is also posing new privacy threats. It, in fact, consists of describing online or offline resources by using free-text labels (i.e. tags), therefore exposing the user profile and activity to privacy attacks. Users, as a result, may wish to adopt a privacy-enhancing strategy in order not to reveal their interests completely. Tag forgery is a privacy enhancing technology consisting of generating tags for categories or resources that do not reflect the user's actual preferences. By modifying their profile, tag forgery may have a negative impact on the quality of the recommendation system, thus protecting user privacy to a certain extent but at the expenses of utility loss. The impact of tag forgery on content-based recommendation is, therefore, investigated in a real-world application scenario where different forgery strategies are evaluated, and the consequent loss in utility is measured and compared.
One of the critical security issues of Vehicular Ad Hoc Networks (VANETs) is the revocation of misbehaving vehicles. While essential, revocation checking can leak potentially sensitive information. Road Side Units (RSUs) receiving the certificate status queries could infer the identity of the vehicles posing the query. An important loss of privacy results from the RSUs ability to tie the checking vehicle with the query's target. We propose a Privacy Preserving Revocation mechanism (PPREM) based on a universal one-way accumulator. PPREM provides explicit, concise, authenticated and unforgeable information about the revocation status of each certificate while preserving the users' privacy.
Tripp, C.; Urquiza, L.; Aguilar Igartua, M.; Parra-Arnau, J.; Rebollo-Monedero, D.; Forne, J.; Pallares, E. Computer standards & interfaces Vol. 36, num. 1, p. 188-197 DOI: 10.1016/j.csi.2013.06.001 Data de publicació: 2013-11-01 Article en revista
Vehicular ad hoc networks (VANETs) have emerged to leverage the power of modern communication technologies, applied to both vehicles and infrastructure. Allowing drivers to report traffic accidents and violations through the VANET may lead to substantial improvements in road safety. However, being able to do so anonymously in order to avoid personal and professional repercussions will undoubtedly translate into user acceptance. The main goal of this work is to propose a new collaborative protocol for enforcing anonymity in multi-hop VANETs, closely inspired by the well-known Crowds protocol. In a nutshell, our anonymous-reporting protocol depends on a forwarding probability that determines whether the next forwarding step in message routing is random, for better anonymity, or in accordance with the routing protocol on which our approach builds, for better quality of service (QoS). Different from Crowds, our protocol is specifically conceived for multi-hop lossy wireless networks. Simulations for residential and downtown areas support and quantify the usefulness of our collaborative strategy for better anonymity, when users are willing to pay an eminently reasonable price in QoS.
Time of Arrival (TOA) based techniques are expected to overcome performance limitations of existing WLAN positioning approaches. The upcoming IEEE 802.11v standard is expected to play a key role because it will include new specific mechanisms for TOA-based positioning with WLAN. This article analyzes some of these new capabilities and evaluates the performance enhancement that they can provide in practice. To this end, a comparative assessment between an existing WLAN TOA-based approach that uses IEEE 802.11 b/g and an analogous solution employing IEEE 802.11v is performed.