Definitions Flashcards
Node
An actor or entity in the network. Also known as ‘vertex’, ‘point’, ‘site’, ‘actor’, ‘entity’, etc
Dyad
A pair of two nodes
Edge
A connection between two nodes. Also known as ‘line’, ‘arc’, ‘link’, ‘tie’, ‘relationship’, ‘connection’
Network
A set of nodes and a set of edge between those nodes
Degree
The degree of a node is the number of edges connected to that node
Directed Network
A network where all edges have a particular direction, so an edge from node v to node u is not the same as an edge from node u to node v
Undirected Network
A network where edges do not have a particular direction, so an edge from node v to node u is also an edge from node u to node v
Indegree
For a directed network, the indegree of a node is the number of incoming edges to that node
Outdegree
For a directed network, the outdegree of a node is the number of outgoing edges from that node
Path
A route from one node to another, following edges on the network. On a directed network, this routed has to follow the direction of the edge
Weighted Network
A weighted network is one where every edge has a particular value or weight, attached to it
Unweighted Network
An unweighted network is one where the value of every edge is the same, there is no particular weight attached to any edge
Shortest Path
The shortest path possible, given the available edges, from one node to another. For a weighted network, the shortest path is the path where the sum of the weights of all edges along the path is lowest. Also called a geodisc.
Distance
The number of edges in the shortest path between two nodes. For a weighted network, the sum of the weights along the shortest path.
Diameter
The longest distance among the distances between all pairs of nodes in the network
Centrality
Some measure for each node indicating how ‘important’ or ‘central’ that node is in the network. Different measure relate to different concepts of ‘central’ in the context of social networks, and there are many such measures available
1. Degree centrality (many paths from this node) -> influence
2. Eigenvalue centrality (high degree to high degree connection) -> more influence
3. Betweeness centrality (many short paths go through central nodes) -> control
4. Closeness centrality (has the most shortest maths) -> independence