The application of Wireless Sensor Networks(WSNs)in forestry has changed the way of traditional forestry resource management,breaking the limitation of traditional collection methods and wide application prospects.The Sink nodes carry the difficult task of aggregating and forwarding the whole network data.How to choose the appropriate Sink nodes according to the network scale and the practical application requirements,is an important research direction.In this paper,we focus on the location problem of Sink nodes in WSNs,and study the location of single-hop Sink node,multi-hop Sink node and multi-sink node repositioning.Firstly,the problem of interval mathematics and PSO is discussed.The problem of singlehop Sink node location is transformed into the global optimization problem of interval mathematics.The monotonicity test and selection strategy are used to determine the subinterval set including the optimal solution.To speed up the global search for the optimal solution speed,to avoid the traditional location algorithm calculation of large,low accuracy defects,reduce node energy consumption.The simulation results show that the interval mathematic optimized PSO is simple and easy to implement.In the interval analysis narrows the optimal value range,all the particles converge to the optimal solution faster.According to the characteristics of multi-hop WSNs,the network energy consumption model is simplified,and the energy efficient location algorithm and the fitness function of the location algorithm for the network life cycle are analyzed.After discretization,though the PSO Sink node optimal position.The simulation results show that the energy efficient location algorithm has low energy consumption,but for the network life cycle of the location algorithm Sink nodes near the neighbor node density,can better collect the data forwarded by the neighbor node to extend the network life cycle.Centroid theory is introduced into the multi-Sink node repositioning algorithm,the Sink node is the mass system,and the amount of data transmitted is the mass of the mass,so that the Sink node is repositioned to the center of mass.The advantages of the algorithm are illustrated by a example,the center-weight re-location algorithm is compared with the multi-Sink node location algorithm and the multi-Sink node re-location algorithm based on COST function.Results show that center-weight re-location algorithm in the network operation,multiple Sink nodes cooperate with each other and gradually approach their respective optimal positions to better extend the network life cycle and improve the success rate of data forwarding. |