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Title: A new framework for context representation, maintenance and discovery in mobile and ad hoc networks
Author: Liu, Qi
ISNI:       0000 0004 2692 3444
Awarding Body: University of Salford
Current Institution: University of Salford
Date of Award: 2009
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In this thesis, a framework has been developed for applying context representation, discovery and sharing within mobile ad hoc networks. This leads to the creation of a Context information Base (CiB) which is used by each device within a mobile ad hoc network to maintain context parameters. In addition to the CiB, a communication protocol, Context information Communication protocol (CiComm) is also developed and integrated into the network to enable nodes to discover and share context information. A contextual module, containing the CiB and CiComm protocol has been written for the NS-2 simulation tool. This enabled a detailed set of simulations to be carried out in order to assess the operation and performance of the overall system. The simulated results confirm the correct operation of the CiB and CiComm protocols and show that context information can be effectively exchanged within mobile ad-hoc networks. Furthermore, the system has been tested under specific conditions such as information loops, device failure and rejoining, all of which arise because of random node movement. According to the results, the performance of the newly formed network is related to network density, its capacity and the movement behaviour of devices in the network. The coupling level is defined to represent the network density; it is proved to be significant to the network since a higher coupling level generates more context information. Network capacity decides bandwidth of the network and how fast contextual traffic can be communicated. Device movement is of importance when it results in nodes leaving and rejoining the network. The framework also shows good performance in a rapid changing environment, compared to SLPManet, which has been used as a benchmark comparison. The discovery success of the CiComm protocol is over 97% in all simulation scenarios. It consumes on average 80% less bandwidth in all scenarios, and spends 50% less time retrieving context information in most scenarios compared to SLPManet. However, the performance of the framework is affected by the density of the ad hoc network. In a high density ad hoc network, retrieving context information using the CiComm protocol takes about 2.2 seconds on average, whereas SLPManet takes about 0.1 second. Overall, the framework presented in this thesis provides a new and more efficient method for managing context within mobile ad hoc networks.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available