Centrality • http: //moviegalaxies. com/ indegree outdegree To Χ έχει σημαντικότερη θέση από το Y betweenness closeness
Αριθμοί normalization divide degree by the max. possible, i. e. (N-1)
real-world examples example financial trading networks high in-centralization: one node buying from many others low in-centralization: buying is more evenly distributed
Κι άλλο παράδειγμα A B C D E n A lies between no two other vertices n B lies between A and 3 other vertices: C, D, and E n C lies between 4 pairs of vertices (A, D), (A, E), (B, D), (B, E) n note that there are no alternate paths for these pairs to take, so C gets full credit
Quiz: Find a node that has high betweenness but low degree
Quiz Q: Find a node that has low betweenness but high degree
Kάλυψη • Spanning tree Initialize: Vnew = {x}, where x is an arbitrary node (starting point) from V, Enew = {} Repeat until Vnew = V: Choose an edge (u, v) with minimal weight such that u is in Vnew and v is not (if there are multiple edges with the same weight, any of them may be picked) Add v to Vnew, and (u, v) to Enew Output: Vnew and Enew describe a minimal spanning tree