基于节点梯度的车辆网络(VANET)路由算法

A Routing-based Node Gradient in Vehicle Ad Hoc Networks

由于节点的高速移动以及拓扑结构的动态性,传统路由协议不能有效地适用于车载自组织网络。为此,利用梯度理论,提出了一种基于节点梯度的路由协议(node gradient routing,NGR)。该协议充分利用节点的特性,计算节点的梯度值,并将梯度值最大的节点作为下一跳的转发节点。在计算梯度值时,考虑到转发节点与目标节点的距离、节点的移动方向、节点的负荷以及节点的周围密度等因素。仿真数据表明提出的NGR具有良好的路由性能,与典型地理路由协议GPSR和Ad Hoc路由协议AODV相比,所提出来的算法的数据包丢包率、端到端传输时延、数据吞吐量方面性能有较大的改善。

By the data of cast thin section, scanning electron microscope, physical property and constant-rate mercury injection, the microscopic pore structure characteristics of Yan 9 reservoir in Zhiluo Oilfield are studied. The result shows that Yan 9 reservoir belongs to middle porosity and middle-low permeability reservoir in Zhiluo Oil field. The main pore types of the reservoir include intergranular dissolved pore, residual intergranular pore and in- tragranular dissolved pore. The pore and throat have general sorting and communication. The capillary pressure curve is divided into I , II , m, Iv types according to the characteristic parameters of pore structure. The type are the main types in the study area. With capillary pressure curve changing from I type to 1V type, the driving pressure and Pc50 increase gradually, and Rcs0 and average pore throat radius decrease gradually, which reflects that pore structure and reservoir property change from good to poor. By comprehensive research of the relationship between characteristic parameters of pore structure and property parameters, it is shown that reservoir property is the result of driving pressure, Pc50, r50 and pore structure parameters and so on.