Seen from 2d on top doesn't show the different sets of nodes fully, but it does show it as partitions. But if spinned at 90 degrees we can see that there are at least three sets. The human actors e.g. teachers and students; the physical learning environment e.g. a course page and linked documents; and the concepts which could be ideas, processes, tasks, goals, beliefs etc.
Fig. 2: network at 90 degrees spin
Note also above that I consider the concept level as the level of abstraction that is used for student modelling, at least with an knowledge overlay method.
My problem with the method of analysis of this network is that a 2-mode network graphing already demands that "In a two-mode network, vertices are divided into two sets and vertices can only be related to vertices in the other set. (De Nooy, Mrvar, & Batagelj, 2005, p. 103)" and I have not yet found the methodology for k-node, or 3-node networks.
De Nooy, W., Mrvar, A., & Batagelj, V. (2005). Exploratory network analysis with Pajek. Cambridge: Cambridge University.