Current Issue : January - March Volume : 2018 Issue Number : 1 Articles : 5 Articles
Wireless charging is an important issue in wireless sensor networks, since it can provide\nan emerging and effective solution in the absence of other power supplies. The state-of-the-art\nmethods employ a mobile car and a predefined moving path to charge the sensor nodes in the\nnetwork. Previous studies only consider a factor of the network (i.e., residual energy of sensor\nnode) as a constraint to design the wireless charging strategy. However, other factors, such as the\ntravelled distance of the mobile car, can also affect the effectiveness of wireless charging strategy.\nIn this work, we study wireless charging strategy based on the analysis of a combination of two\nfactors, including the residual energy of sensor nodes and the travelled distance of the charging car.\nFirstly, we theoretically analyze the limited size of the sensor network to match the capability of\na charging car. Then, the networked factors are selected as the weights of traveling salesman problem\n(TSP) to design the moving path of the charging car. Thirdly, the charging time of each sensor node\nis computed based on the linear programming problem for the charging car. Finally, a charging\nperiod for the network is studied. The experimental results show that the proposed approach can\nsignificantly maximize the lifetime of the wireless sensor network....
In directional wireless sensor networks (DSNs), sensor nodes with directional antennas provide extended network\nlifetime and better coverage performance. However, one of the key challenges of directional nodes is to discover their\nneighbors due to difficulty in achieving synchronization among their directed transmissions and receptions. Existing\nsolutions suffer from high discovery latency and poor percentage of neighbor discovery either due to lack of proper\ncoordination or centralized management of the discovery operation. In this work, we develop a collaborative\nneighbor discovery (COND) mechanism for DSNs. Each COND node polls to directly discover its neighbors in a\ndistributed way and collaborates with the already discovered nodes so as to allow indirect discovery. It helps to\nincrease the neighbor discovery performance significantly. A Markov chain-based analytical model is developed to\nquantify theoretical performances of the proposed COND system. The performance of the COND system is evaluated\nin Network Simulator Version 3, and simulation results reveal that it greatly reduces the discovery latency and\nincreases neighbor discovery ratio compared to state-of-the-art approaches....
The node replication attack is one of the notorious attacks that can be easily launched by adversaries in wireless sensor networks.\nA lot of literatures have studied mitigating the node replication attack in static wireless sensor networks. However, it is more\ndifficult to detect the replicas in mobile sensor networks because of their node mobility. Considering the limitations of centralized\ndetection schemes for static wireless sensor networks, a few distributed solutions have been recently proposed. Some existing\nschemes identified replicated attacks by sensing mobile nodes with identical ID but different locations. To facilitate the discovery\nof contradictory conflicts, we propose a hybrid local and global detection method. The local detection is performed in a local area\nsmaller than the whole deployed area to improve themeeting probability of contradictory nodes, while the distant replicated nodes\nin larger area can also be efficiently detected by the global detection. The complementary two levels of detection achieve quick\ndiscovery by searching of the replicas with reasonable overhead....
The recent advances in sensing and communication technologies such as wireless sensor networks (WSN) have enabled low-priced\ndistributed monitoring systems that are the foundation of smart cities. These advances are also helping to monitor smart cities and\nmaking our living environments workable. However, sensor nodes are constrained in energy supply if they have no constant power\nsupply. Moreover, communication links can be easily failed because of unequal node energy depletion. The energy constraints\nand link failures affect the performance and quality of the sensor network. Therefore, designing a routing protocol that minimizes\nenergy consumption and maximizes the network lifetime should be considered in the design of the routing protocol for WSN. In\nthis paper, we propose an Energy-EfficientUnequal Chain Length Clustering (EEUCLC) protocol which has a suboptimalmultihop\nrouting algorithm to reduce the burden on the cluster head and a probability-based cluster head selection algorithm to prolong the\nnetwork lifetime. Simulation results show that the EEUCLC mechanism enhanced the energy balance and prolonged the network\nlifetime compared to other related protocols....
In a network, a distributed consensus algorithm is fully characterized by its weighting\nmatrix. Although there exist numerical methods for obtaining the optimal weighting matrix,\nwe have not found an in-network implementation of any of these methods that works for all\nnetwork topologies. In this paper, we propose an in-network algorithm for finding such an optimal\nweighting matrix....
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