Comparison of city networks centrality in different years (Degree centrality and betweenness centrality).

Note:Local Centrality (Cad) measures the ability of a city to carry out scientific cooperation with other cities, using the following formula:(1)where Rai is the intercity network connectivity degree between city a and city i.(1)Betweenness Centrality (Cab) was used to measure the controlling degree of a city on scientific knowledge. Its expression is as follows:(2)(2)where Gjk indicates the number of geodesic paths between city j and city k; Gjk(a) describes the number of geodesic paths between city j and city k, which pass city a. The geodesic path is the strongest connective path between two cities.Comparison of city networks centrality in different years (Degree centrality and betweenness centrality).