No abstract

Abstract-Packet forwarding in Public TransportNetworks is particularly challenging due to the high mobility, rapidly changing topology and intermittent connectivity observed in these networks. Though clustering of nodes can aid forwarding decision in these Delay Tolerant Networks (DTNs), the clustering process is extremely costly in a large network. In this paper, we introduce a generic efficient clustering method which is suitable for grouping the nodes of large networks. We also demonstrated how encounter frequencies of public transport networks can be fed to that clustering algorithm in order to build clusters of nodes. And finally, our large scale extensive simulation study on real bus traces shows the efficacy of clustering in packet forwarding.

No abstract

The security features of current digital services are mostly defined and dictated by the service provider. A user can always decline to use a service whose terms do not fulfil the expected criteria, but in many cases even a simple negotiation might result in a more satisfying outcome. This article aims at making the building of non-repudiable security service level agreements between a user and a service provider more feasible. The proposed mechanism provides a means to describe security requirements and capabilities in different dimensions, from overall targets and risks to technical specifications, and it also helps in translating between the dimensions. A negotiation protocol and a decision algorithm are then used to let the parties agree upon the security features used in the service. This article demonstrates the feasibility and usability of the mechanism by describing its usage scenario and proof-of-concept implementation, and analyzes its nonrepudiability and security aspects.

No abstract