The centralized system encounters two vital issues, the central server needs to perform genuine calculation and communication with the vehicles continuously, which can make such architecture infeasible for extensive zones with various vehicles; and driver security is not guaranteed since the drivers need to share their area furthermore the beginning stages and goal of their excursion with the server, which may keep the acknowledgment of such courses of action. To address these issues, a half and half vehicular rerouting structure is enlivened. The structure off-weights a tremendous part of the rerouting figuring at the vehicles, and therefore, the re-coordinating system gets the opportunity to be useful persistently. To settle on group rerouting decisions, the vehicles exchange messages over vehicular extraordinarily delegated frameworks. The system is hybrid since notwithstanding it uses a server to choose an exact overall point of view of the development more than 2G/3G affiliation. Likewise imperative is that the customer security is balanced with the rerouting ampleness. SCMS issues advanced endorsements to taking an interest vehicles for setting up trust among them, which is imperative for prosperity applications in perspective of vehicle-to vehicle correspondences. It underpins four principal use cases, to be particular, bootstrapping, endorsement provisioning, bad conduct reporting and renouncement. The principle outline goal is to give both security and insurance to the greatest degree sensible and possible. To fulfill the last specified, vehicles are issued pseudonym certificates, and the provisioning of those supports is partitioned among different affiliations. One of the essential challenges is to energize capable renouncement while giving insurance against attacks from insiders.

Abstract-Traffic congestion causes driver frustration and costs billions of dollars annually in lost time and fuel consumption. This paper presents five traffic rerouting strategies designed to be incorporated in a cost-effective and easily deployable vehicular traffic guidance system that reduces travel time. The proposed strategies proactively compute individually tailored rerouting guidance to be pushed to vehicles when signs of congestion are observed on their route. The five proposed strategies are the dynamic shortest path (DSP), the A * shortest path with repulsion (AR * ), the random k shortest path (RkSP), the entropy-balanced kSP (EBkSP), and the flow-balanced kSP (FBkSP). Extensive simulation results show that the proposed strategies are capable of reducing the travel time as much as a state-of-the-art dynamic traffic assignment (DTA) algorithm while avoiding the issues that make DTA impractical, such as the lack of scalability and robustness, and high computation time. Furthermore, the variety of proposed strategies allows tuning the system to different levels of tradeoffs between rerouting effectiveness and computational efficiency. In addition, the proposed traffic guidance system can significantly improve the traffic even if many drivers ignore the guidance or if the system adoption rate is relatively low.

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Riding the wave of smart disclosure initiatives and new privacy-protection regulations, the Personal Cloud paradigm is emerging through a myriad of solutions offered to users to let them gather and manage their whole digital life. On the bright side, this opens the way to novel value-added services when crossing multiple sources of data of a given person or crossing the data of multiple people. Yet this paradigm shift towards user empowerment raises fundamental questions with regards to the appropriateness of the functionalities and the data management and protection techniques which are offered by existing solutions to laymen users. These questions must be answered in order to limit the risk of seeing such solutions adopted only by a handful of users and thus leaving the Personal Cloud paradigm to become no more than one of the latest missed attempts to achieve a better regulation of the management of personal data. To this end, we review, compare and analyze personal cloud alternatives in terms of the functionalities they provide and the threat models they target. From this analysis, we derive a general set of functionality and security requirements that any Personal Data Management System (PDMS) should consider. We then identify the challenges of implementing such a PDMS and propose a preliminary design for an extensive and secure PDMS reference architecture satisfying the considered requirements. Finally, we discuss several important research challenges remaining to be addressed to achieve a mature PDMS ecosystem.