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Pervasive computing applications aim to provide appropriate services that respond directly to their users and environments, with greatly reduced explicit human guidance. These applications usually adapt to changing failure-prone context information which was acquired from various sources that differ in quality and format. To efficiently acquire, share, correlate, and reason over raw existing context data, they must be modeled in a homogenous fashion. In this paper, we propose a hybrid context modelling approach, which attempt to integrate the advantages of object-oriented model and ontology-based model for their distributed context handling and efficient context reasoning respectively. We have applied this model to the development of a context management middleware which providing an extensible application framework for monitoring and assisting the elderly at home environments.

In order to reduce the average path length of the wireless sensor networks (WSNs) and save the energy, in this paper, the concept of the small world is introduced into the routing designs of WSNs. So a new small world routing protocol (SWRP) is proposed. By adding a few short cut links, which are confined to a fraction of the network diameter, we construct a small world network. Then the protocol finds paths through recurrent propagations of weak and strong links. The simulation results indicate that SWRP reduces the energy consumption effectively and the average delay of the data transmission, which leads to prolong the lifetime of both the nodes and the network.

The increasing P2P network traffic on the Internet has leaded to the problem of network congestion. In the consequence of the diversification of the P2P business and protocol, research on the management of P2P traffic has many problems to resolve. Prediction of the P2P traffic is the kernel problem in the P2P traffic management. Based on the existed P2P traffic characters, this paper structures a P2P traffic model, gives a traffic prediction algorithm bases on wavelet-analysis, and proves the accuracy of the algorithm. Simulation experiment figures that the algorithm has a high prediction precision and a superior real-time performance.

In view of the irrationality that traditional virtual potential field algorithms brought about on the criterion for the generation of virtual force in directional sensor networks, we propose a novel criterion for judgment. Cross-set test is used to determine whether the sensory region has any overlap, thereby restrain the energy cost of nodes and the performance of the algorithm is improved. In simulation experiment, the validity of the novel criterion and IAPD (improved algorithm of virtual potential field in directional sensor networks) are verified by the compare of IAPD and traditional virtual field algorithms.