Prophet_TD Routing Algorithm Based on Historical Throughput and Encounter Duration

Opportunistic networks are self-organizing networks that do not require a complete path between the source node and the destination node as it uses encounter opportunities brought by nodes movement to achieve network communication.Opportunistic networks routing algorithms are numerous and can be roughly divided into four categories based on different forwarding strategies.The Prophet routing algorithm is an important routing algorithm in opportunistic networks.It forwards messages based on the encounter probability between nodes,and has good innovation significance and optimization potential.However,the Prophet routing algorithm does not consider the impact of the historical throughput of the node on message transmission,nor does it consider the impact of the encounter duration between nodes on message transmission.Therefore,to improve the transmission efficiency of opportunistic networks,this paper based on the Prophet routing algorithm,fuses the impact of the historical throughput of the node and the encounter duration between nodes on message transmission at the same time,and proposes the Prophet_TD routing algorithm based on the historical throughput and the encounter duration.This paper uses the Opportunistic Networks Environment v1.6.0(the ONE v1.6.0)as the simulation platform,controls the change of running time and the number of nodes respectively,conducts simulation experiments on the Prophet_TD routing algorithm.The simulation results show that compared to the traditional Prophet routing algorithm,on the whole,the Prophet_TD routing algorithm has a higher message delivery rate and a lower network overhead rate,and its average latency is also lower when node density is large.

Wet-Dry Runoff Correlation in Western Route of South-to-North Water Diversion Project,China

The Western Route of the South-to-North Water Diversion Project is an important trans-basin diversion project to transfer water from the upstream Yangtze River and its tributaries （water-exporting area）, to the upstream of the Yellow River （water- importing area）. The long-term hydrologieal data from 14 stream gauging stations in the Western Route area and techniques including the pre-whitening approach, non-parametric test, Bayes, law, variance analysis extrapolation, and Wavelet Analysis are applied to identify the streamflow eharacteristics and trends, streamflow time series cross-correlations, wetness-dryness encountering probability, and periodicities that occurred over the last 50 years. The results show that the water-exporting area, water- importing area, and the streteh downstream of the water-exporting have synehronization in high-low flow relationship, whereas they display non- synchronization in long-term evolution. This corresponds to the complicated and variable climate of the plateau region. There is no obvious increasing or decreasing trend in runoff at any gauging station. The best hydrological eompensation probability for rivers where water is diverted is about 25% to lO%, and those rivers influenced significantly by diversion are the Jinsha and Yalong rivers. Proper planning and design of compensation reservoirs for the water-exporting area and stretch downstream of the water- exporting area can increase the hydrological compensation possibility from water-exporting area to the water-importing area, and reduce the impact on the stretch of river downstream of the water- exporting area.