Linked Activity Spaces: Embedding Social Networks in Urban Space - Computational Approaches for Urban Environments - page 314

Fig. 13.6 An ego in focus ( solid pink ) shares POIs to various extents with each of his or her alters
( dashed lines ). The pattern shows that the focal ego and friends use the downtown area. One friend
seems to use the Western area of the city more than the other friends

13.4 Results

13.4.1 Dyadic Relationships

We find that a pair of friends is more likely than a random pair to use the same
places in Jiamusi. 11 % of friends and 50 % of random pairs share no POIs. Of
pairs who share POIs, friend pairs share an average of 55.8 POIs, and a random pair
shares 45.77 out of 212 total possible POIs (Fig. 13.7 a). A t -test using the ellipse
activity-space method yields a t -value of 56.03 (degree of freedom ( df )) D 44,706,
p -value < 0.001) and allows us to reject the null hypothesis that the mean difference
between these two groups is insignificant, indicating that friends share more POIs
than random pairs.
Second-degree friends also utilize urban infrastructure significantly more simi-
larly, in terms of shared POIs, than random users (Fig. 13.7 b). The t -value is 94.82
( df D 152,070, p -value < 0.001). The count of POIs shared by second-degree friends
on average is 55.23 compared to 45.77 for random pairs.