Measurement And Application Of Urban Structural Resilience From The Perspective Of Multi-dimensional Networks

As a new concept in the field of urbanology,urban structural resilience focuses on the ability of a city to withstand and adapt to uncertain external shocks,recover its own structure from the crisis and expand new structural paths,which is conducive to the healthy and stable development of urban system.However,there are significant differences in the resilience of different regions in the face of the same external impact.The strength of resilience directly leads to the difference of urban economic development and the fragility of urban structure,which is one of the problems that need to be solved in the process of sustainable and healthy urban development.This study first comprehensive urban basic elements and spatial structure index,using social network analysis from the economic,social and ecological three dimensions to build multidimensional city association network,select transitivity,diversity and centricity structure indexes as urban structure toughness measurement evaluation indexes,constructing urban structure toughness measurement system;Secondly,based on the above structural toughness measurement system,the structural toughness level of 31 provincial capitals in China from 2011 to 2018 was measured.Finally,the paper takes the COVID-19 outbreak as the external impact background,constructs the urban flow spatial network based on the flow factors of people,information flow and capital flow,explores the change trend of the social structure resilience index of the urban agglomeration in the middle reaches of the Yangtze River under the impact of the epidemic,and then puts forward the conclusions and prospects of the paper.To provide policy recommendations for urban agglomerations in the post-epidemic era to improve structural resilience,restore highquality development and strengthen regional economic recovery.The main research conclusions are as follows:1.By measuring the structural resilience of provincial capitals in China from 2011 to2018,it can be seen that the urban linkage network presents a "core-periphery" structural feature,and the economic structural resilience,social structural resilience and ecological structural resilience of provincial capitals have all improved over time.First-tier cities,such as Beijing and Shanghai,have strong economic structural toughness and fast factor transmission speed.They are able to adapt to the changing external environment,accelerate learning,innovation and resource exchange among cities,and enhance their resilience to crises.They are the core nodes of the economic connection network.Chongqing's social structural resilience tops the list due to its far larger population than other cities.Wuhan is densely populated with scientific research institutes and universities,and the policy of talent introduction continues to release.As a result,its social structural resilience is relatively strong and it occupies a core position in the social network.Nanjing and Guangzhou have high greening coverage rate,low pollutant emission,high resilience of ecological structure and strong environmental pressure bearing capacity,while Harbin,Changchun and other heavy industry intensive areas have large pollutant emission and overloaded ecosystem,which are at the edge of the ecological network,and low resilience of ecological structure.2.The sudden COVID-19 epidemic had a significant short-term impact on the social structural resilience of the urban agglomeration in the middle reaches of the Yangtze River.The population flow network structure became sparse and the social structural resilience weakened;With the gradual downgrading of emergency response and the orderly progress of resumption of work and production,the toughness of social structure in regions except Hubei Province picked up to some extent.Because of the sudden characteristics of the epidemic,the search frequency of cities increases sharply,and the resilience of urban social structure in the information flow network is enhanced.With the gradual elimination of newly confirmed cases and the normalization of epidemic prevention and control,the resilience of urban social structure has slowed down,and Wuhan still maintains its position as the core hub of information flow.The epidemic accelerated the inflow of funds and epidemic prevention materials into Wuhan and other cities in Hubei Province,and the intensity of inter-city correlation increased significantly.With the lifting of the blockade in some areas and the easing of the shortage of capital inventory,the resilience of the social structure of cities in the capital flow network has fallen.