中文摘要：

主要研究双层无线传感网络模型,即数据信息流只能在传感器和中继器或中继器和中继器之间传输,而不能在传感器之间传输。近似算法基于两个子问题：k圆盘覆盖问题和单层传感网络的k连通问题,而后在部分中继器周围设置＂等六边形＂结构的中继器点,最终达到整个网络的3-连通水平。该算法的最终性能比为8α＋β,其中α为k圆盘覆盖近似算法的性能比,β为单层传感网络的k连通近似算法的性能比

英文摘要：

The two-tiered wireless sensor network is a network that data can only be transmitted between relay nodes or sen-sor nodes and relay nodes,and there is no data stream between sensor nodes.An approximation algorithm is proposed basedon two foundational works：The k-disk cover problem and the single-tiered 3-connectivity relay node placement problem,witha special structure,called＂hexagon＂,to keep 3-connectivity for the network.The performance ratio is 8α＋β,where α is theperformance ratio of approximation algorithm for the k-disk cover problem,and β is the performance ratio of approximationalgorithm for the single-tiered 3-connectivity relay node placement problem