week 2 - graph theory Flashcards
what is network topology?
properties of a network that are unrelated to where the nodes are in space, instead it just matters the connection between nodes and edges
What are the different types of graph theoretical measures?
Local - properties of each node e.g degree
Meso-scale - properties of sub networks
Global network properties
what is edge density?
num actual edges/ num possible edges
how to calculate number of possible edges?
N*(N-1)/2
(removes the diagonal and the lower triangular part)
what are components in the network?
sets of nodes that aren’t connected to any other components
what is average edge weight?
the average of existing edges within the upper triangular
what is degree?
number of edges connecting a node
what is the strength of a node?
sum of edge weights connected to a node?
What is eigenvector centrality?
To what extent is the node connected to other nodes with high eigenvector centrality
what is path length?
the number of edges between two nodes
what is characteristic path length?
the average path length between all node pairs
what is global efficiency?
average inverse shortest path length
what is betweenness centrality?
the fraction of shortest paths in an entire network that pass through a given node
describe the spectrum of communication processes
from diffusion to routing
In diffusion, the structure of the network is unknown and the walk through the network is random
In routing you take the shortest path, this requires full knowledge of the network topology
what is the clustering coefficient?
the fraction of a nodes neighbours that are connected
what is the global clustering coefficient?
the average nodal clustering coefficient
what is transitivity?
the ratio of triangles to triplets in the network
what is a module? what about in fmri
subnetworks of nodes that are very densely connected with each other and sparesly connected to other modules
in fMRI this is the resting state networks e.g DMN, DAN
what are hub nodes?
Important nodes that are very highly connected
connector hubs = connections with nodes in different communities
Provincial hubs = have many connections with different communities
what is rich club?
A set of nodes that have high degree that are highly connected to each other
rich clubs tend to integrate modules together
what is segregation? and measures related
locally, densely connected clusters of nodes
clustering, transivity and modularity
what is integration?
the ability of
