About SNA

SNA is the process and corresponding result of analysis on the relationship and interaction among social network's actors, in my opinion.

Besides the graph

The social network can be described as sociomatrix 

	Alice	Bob	Carol	David	Eva
Alice	-	1	1	1	0
Bob	1	-	0	1	0
Carol	1	0	-	1	0
David	1	1	1	-	1
Eva	0	0	0	1	-

From first view I think David is the most influential because he is the only one who connects to all other students. Then I use Betweenness Centrality to solve the problem. Because Betweenness Centrality is a measure of the potential for control as an actor who is high in “betweenness” is able to act as a gatekeeper controlling the flow of resources between the alters that he or she connects. On the other hand, the answer is too simple and obvious if we use Degree Centrality, and closeness is not so significant as betweenness in this case if we use Closeness Centrality. So to judge with Betweenness Centrality is the most appropriate in my mind.

According to the formula

I obtain the result

	Betweeness Centrality
Alice	0.8
Bob	0
Carol	0
David	0.58
Eva	0

And it proves that my previous guess is right. David is the most influential due to his most connections and his significant place to act as gatekeeper.