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Wireless Backbone Networks (WBNs) equipped with Multi-Radio Multi-Channel (MRMC) configurations do experience power control problems such as the inter-channel and co-channel interference, high energy consumption at multiple queues and unscalable network connectivity. Such network problems can be conveniently modelled using the theory of queue perturbation in the multiple queue systems and also as a weak coupling in a multiple channel wireless network. Consequently, this paper proposes a queue perturbation and weakly coupled based power control approach for WBNs. The ultimate objectives are to increase energy efficiency and the overall network capacity. In order to achieve this objective, a Markov chain model is first presented to describe the behaviour of the steady state probability distribution of the queue energy and buffer states. The singular perturbation parameter is approximated from the coefficients of the Taylor series expansion of the probability distribution. The impact of such queue perturbations on the transmission probability, given some transmission power values, is also analysed. Secondly, the inter-channel interference is modelled as a weakly coupled wireless system. Thirdly, Nash differential games are applied to derive optimal power control signals for each user subject to power constraints at each node. Finally, analytical models and numerical examples show the efficacy of the proposed model in solving power control problems in WBNs.

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Background: The indigenous healers or traditional doctors play a significant role in the healthcare provisioning in Africa. Although traditional healing has been in practice for several centuries, very little has been achieved in terms of harvesting the wealth of tacit knowledge possessed by these practitioners for future references.Objective: The objectives of this article were twofold. The first objective was to capture the tacit knowledge possessed by traditional healers in Mozambique. The second objective was to enhance preservation of tacit knowledge for sharing and training of other traditional healers.Method: The cognitive semiotic model was used as a basis for capturing the tacit knowledge. Qualitative and quantitative data were collected by using interviews and questionnaires were applied during systems requirements elucidation, designing the user interface and in building the knowledge repository. In the requirement elucidation phase, 13 traditional doctors were interviewed. Besides text and voice recordings, video recordings and photos were used in capturing the tacit knowledge. The usability of the system was tested by using the heuristic evaluation technique.Results: The findings revealed that the system developed could be used for capturing the tacit knowledge and storing it in an explicit form. The usability tests indicated that the prototype developed served its purpose to a great extent.Conclusion: The study concludes that cognitive semiotic model is a suitable tool for capturing tacit knowledge of traditional doctors in Mozambique. The results of the usability evaluation confirm that the system developed supports information sharing and ease of use. It is observed that the developed application could support users with little formal education. However, some basic computer literacy training would assist in maximising the benefits of the system.