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Ad hoc networks present special issues that often makes classical approaches for network analysis insufficient. In this paper we propose a new methodology to study communication protocols and architectures in ad hoc networks. Usually, solutions for ad hoc scenarios are analyzed and evaluated through simulative tools. The paper shows limitations of the traditional simulative approach and the improvements that the Discrete Fourier Transform analysis can produce if it is applied on the results from simulations. The proposed methodology gets advantages (such as simplicity and flexibility) from simulative investigation approaches overcoming the great drawback of loss of information on rare events. In fact, it transfers the time-dependent measurements into the frequency domain allowing to point out the occurrence of events which take place only under particular conditions and to detect occasional misbehaviors of the system. For these reasons the presented technique is suitable for both protocol debugging and system performances evaluation.

Sketches something of the pace and scale of transformation in the structure of the labour force between 1978-1996. Expectations of lifelong employment, welfare provision and a pension (all guaranteed to urban workers under the 'iron rice bowl' system) are increasingly threatened by rising unemployment and privatisation of welfare services. Reviews Mao's legacy in 'the worker's state' and considers how far China has moved towards a market-determined system of labour allocation and rewards. Also considers how far the changes result from the incursion of market forces, and the structural features and institutional legacies that are shaping the emergence of labour markets. (Quotes from original text)

Governmental institutions all over the world are trying to increase the level of security of their countries emphasizing the usage Information Technology solutions. We believe that Cloud Computing may strongly help Homeland Security, since it offers a very flexible support for organizing and managing heterogeneous systems, providing huge amount of processing, storing and sensing resources. In this work we introduce a new Cloud architecture able to virtualize different types of sensing environments in virtual sensing elements, logically belonging to Cooperating Clouds. It represents a very flexible solution, which offers seamless, secure and advanced services to support Homeland Security.

Wireless multi-hop networks have drawn great attention from research and business communities, since they suit well diverse application scenarios, such as environmental monitoring, military support in hostile environments and emergency applications. However, this challenging communication paradigm requires solutions able to fit specific requirements in terms of resource constrains, node mobility and quality of service. Random Walks (RWs) are probabilistic approaches to perform distributed operations, such as data search and retrieval. They are effective and have relatively small overhead compared to classic schemes, such as flooding. To further improve performance of RWs, hybrid solutions may be employed. Such strategies increase system performance at the cost of additional energy consumption. In this work, we propose two novel schemes that exploit local topological information in order to increase the hybrid RW protocols performance. Through simulations, we compare hybrid protocols with a traditional RW solution, studying their performance in static and mobile scenarios. An analysis of the trade-off between the number of node revisits and energy consumption allows to identify the more fitting protocols for different application scenarios in wireless multi-hop networks. Advantages and drawbacks of different RW strategies are highlighted, along with research challenges that need to be investigated in the future. (C) 2011 Elsevier B.V. All rights reserved.