Research On The Distribution Of Sites In Urban Logistics UAV Distribution Network Based On Complex Network Theory Model

In recent years,the increasing number of express and take-out orders as well as the proliferation of e-commerce businesses have inspired a significant growth in the logistics industry,with rapid development in international,domestic and inter-city logistics industries.The development of drones in the field of logistics and delivery is also becoming increasingly mature.Countries are currently building a framework for UAV air traffic management(UAS Traffic Management,UTM)for UAV(Unmanned Aerial Vehicle)in airspace below 120 m.With the rapid development of urban logistics and UAV-related fields,urban aerial logistics transportation using electric propulsion-based UAVs as carriers has become an emerging urban logistics distribution method,and urban logistics distribution using UAVs will certainly achieve networked operation in the future,and the identification of key sites in the network is a key issue to be considered.In this thesis,we abstract the urban logistics UAV distribution network as a directed weighted network model based on the knowledge of complex network theory,in which individual UAV takeoff and landing sites are used as the nodes of the network,the traffic interaction between the sites is used as the connected edges of the network,and the cargo flow between the sites is used as the edge weight of the network.Taking the South High-tech District of Chengdu City as an example,the statistical feature quantities of each site in the network are calculated,and the alternative sites of the logistics drone delivery network are analyzed according to the calculated values of the weight,degree,betweenness and clustering coefficient.Among these characteristic quantities,the weight describes the size of the cargo flow occurring and attracted by the site;the degree describes the degree of connectivity of the site in the network;the betweenness is a global indicator,which evaluates the influence of the site in the network more comprehensively;the clustering coefficient describes the size of the site traffic or the tightness of connectivity in the "small world" according to the actual situation.In order to comprehensively evaluate the importance of sites to give the final recommendation of the first sites opening order,the evaluation system of the importance of network nodes is constructed.Since the cargo traffic is taken into account in the network,three evaluation indexes are selected from the perspectives of node-based relevance,maximum traffic routes,and small-worldness: degree,betweenness,and clustering coefficient.The weights of each index were determined by the coefficient of variation method,and the greatest weight was given to the betweenness number.The TOPSIS comprehensive evaluation method is used to obtain the comprehensive index value of each site importance,rank the sites in importance,and the top ten sites in importance are the key sites.Considering the priority of opening logistics drone distribution sites at key nodes can meet the logistics demand and complete the logistics distribution tasks as much as possible,and maintaining these key sites more is beneficial to enhancing the reliability of the whole logistics distribution network.