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Abstract: In this paper we propose a system architecture for enabling mobile nodes to query a largely deployed wireless sensor network in an intelligent transportation system scenario. We identify three different types of nodes in the network: mobile sinks (i.e. the nodes moving and querying the WSN), vice-sinks (i.e. nodes able to communicate directly with mobile sinks) and ordinary sensor nodes (i.e. nodes sensing a phenomenon and communicating in a multihop fashion). We present protocols and algorithms specifically tailored to such a scenario, in particular at the MAC and network layers. Such a reference architecture well covers situations in which WSNs deployed in a parking place or along a road, provide to cars information on the conditions of the surrounding environment. We introduce and analyse a simple geographic routing protocol and two different load balancing techniques. The performance of the proposed solutions is evaluated through extensive simulations. The simple geographic routing is compared to load balancing techniques. Results support the capability of the proposed solutions to enable the introduction of novel intelligent transportation system applications. [Copyright &y& Elsevier]

Delay-tolerant networks, consisting of a number of intermittently connected wireless devices, are emerging as a promising application field, able to complement in some situations infrastructure-based service delivery. In this work, we propose a marked point process model for characterizing the pattern of contacts among nodes in such systems. The model can be used for deriving analytical results on various performance indexes. Validation of the model is performed through comparison with experimental traces obtained from real-world DTN deployments. [ABSTRACT FROM AUTHOR]

An introduction to the journal is presented in which the editor discusses various reports published within the issue including one by S. Borst and Y. Al-Harthi on "Distributed Adaptive Algorithms for Optimal Opportunistic Medium Access," one by W. Saad and colleagues on the game-theoretical method for physical layer security problem in wireless networks, and one by E. Altman, K. Avrachenkov, and A. Garnaev on "Jamming in wireless networks under uncertainty."