The Evolvement Of Urban Network Structure In Urban Agglomeration In The Middle Reaches Of The Yangtze River

With the rocketing process of world economic globalization and information technology, urban agglomeration has become the basic unit of the world economic ties and energy exchange, and it has become the main form of economic development and new-type urbanization. Therefore, fostering urban agglomerations has become the common strategy of promoting regional comprehensive competitiveness, and effectively organizing its spatial structure is the key to realize the sustainable development. The substantive characteristic of spatial structure of urban agglomeration is tight economic networks among cities and industries, and it has appeared in some urban agglomerations that in the higher stage. Moreover, some cities are promptly embedded in local and global production networks. The real stage and evolution characteristic of the city network cannot be reflected from a hierarchical and size perspective. Hence, the research paradigm in city systems urgently requires of transforming to the urban network research.This paper takes the urban agglomeration in the Middle Reaches of the Yangtze River (MRYR) as its study area and follows the empirical path that companies internal network-based on the county level. First, we get business directory from 11315 national enterprise credit system, imports business directory into the national enterprise credit information publicity system for confirming and adding information, and establishes companies network database. Second, under three time cross sections, 2000,2007 and 2014, we use social network analysis (SNA) and industry-wide companies network to analyze the spatial structure evolution of urban network of the urban agglomeration in the MRYR. Third, we use SNA and producer service companies network to analyze the spatial structure evolution of city network in the urban agglomeration in the MRYR, and compare it with above. Besides, we attempt to analyze the influence of transportation accessibility on urban network by utilizing panel data model.The major findings include:(1) the urban network of the urban agglomeration in the MRYR based on industry-wide companies network has rapidly developed but in the early stages, and characteristics of its spatial structure include polycentrity, hierarchy and administrative boundary segmentation (provincial level); the node analysis shows that the degree centrality is on the rise at the same time differences in expanding, spatial distribution of out-degree centrality is more dispersed, and structural hole resource that central cities hold is reducing but still high; the spatial structure has experienced the evolution of "polarization, equilibrium, and re-polarization"; small group phenomenon is obvious, and characteristics of subgroups’spatial distribution include administrative boundary segmentation (provincial level), consolidation and close connection. (2) the urban network based on producer service companies network develops more rapidly, and its spatial structure is similar as a whole. In addition, control force has been tightly packed in just a few cities, while attractive force has been more decentralized. (3) transportation accessibility has continued to improve, and its spatial structure has a tendency towards equilibrium, but still has a great imbalance; in addition, it has exerted an active effect on the urban network.