The final FPSN presented in Figure 6 is an outcome of the bottom-up approach where the HPSN from Figure 5 is flattened to level 1 (7).
An example of top-bottom approach is presented below where the HPSN from Figure 7 is flattened to level 3 (Z), that is, to FPSN in Figure 8.
The flat presocial network structure (FPSN) is used to extract the social network (SN) where the relations user-object from FPSN no longer exist.
(d) Extraction of relations user_from-user_to is by calculation of the relationship strengths and colours (labels) between SN nodes (users) using activity data stored in FPSN. There are many possible formulas for calculating the relationship strength.