Abstract Limited energy is the major driving factor for research on wireless sensor networks. Clustering alleviates this energy shortage problem by reducing data traffic conveyed over the network and therefore several clustering methods are proposed in the literature. Researchers put forward their methods by making serious assumptions such as always locating single sink at one side of the topology or making clusters near to... Limited energy is the major driving factor for research on wireless sensor networks. Clustering alleviates this energy shortage problem by reducing data traffic conveyed over the network and therefore several clustering methods are proposed in the literature. Researchers put forward their methods by making serious assumptions such as always locating single sink at one side of the topology or making clusters near to the sink with smaller sizes. However, to the best of our knowledge, there is no comprehensive research that investigates the effects of various structural alternatives on energy consumption of wireless sensor networks. In this paper, we thoroughly analyze the impact of various structural approaches such as cluster size, number of tiers in the topology, node density, position and number of sinks. Extensive simulation results are provided. The results show that the best performance about lifetime prolongation is achieved by locating a sufficient number of sinks around the network area. Read More Read Less

Abstract Next generation Networks (NGN) are required to support the seamless delivery of voice, video and data with high quality. One of the most important key features of NGN is Quality of Service (QoS), which has been a focal point of NGN research, development and standardization. In this work, we propose and demonstrate an efficient NGN QoS-Aware resource and admission control and management methodology... Next generation Networks (NGN) are required to support the seamless delivery of voice, video and data with high quality. One of the most important key features of NGN is Quality of Service (QoS), which has been a focal point of NGN research, development and standardization. In this work, we propose and demonstrate an efficient NGN QoS-Aware resource and admission control and management methodology which guarantees the QoS requirements. The advantages of the proposed method, in terms of QoS gains, are demonstrated through modeling of the main QoS parameters. Simulation results are derived to evaluate the performance of the proposed method in terms of supporting the QoS and improving the transport network scalability. Read More Read Less