Tuesday, October 11, 2011

Basic Social Network Analysis Criterion

Just finished two interesting papers which analyze social networks: Planetary-Scale Views on a Large
Instant-Messaging Network (Leskovec, Horvitz) and Statistical Analysis of Real Large-Scale Mobile Social Network (Zhengbin Dong, Guojie Song, KunqingXie, Ke Tang, JingyaoWang).

The former was an a an analysis of a month's worth of MSN Messenger traffic and network structure. The latter, an analysis of chinese phone log and corresponding network structure. 

Though the results were interesting (I won't share them here), I was actually looking for the criterion they analyzed: 
  • Degree: simply put, the number of connections a user (node) has. 
  • Shortest Path: the fewest number of users between two users. 
  • Diameter: the largest shortest path in a network. 
  • Clustering Coefficient: the ratio of actual connections a user has to potential connections. Measures  the transitivity of a network (ie the propensity for your friends to also be friends themselves).
  • Betweenness Centrality: the ratio of the count of shortest paths (between user A and user B) that pass through a user (user C) to all shortest paths (between user A and user B).
  • K-Core Distribution of Component Size: gives us an idea of how quickly the network shrinks as we move towards the core. Or, how large (number of users/ nodes) is the core component when a constraint of the minimum degree (k) is applied. (ie for a network where nodes have degree, k >20, how many total nodes in the component?)
Most of these characteristics are represented as a distribution (ie what is the degree distribution of all nodes in a network?) and tend to provide insight into the stability and density of a network. For example, a network with a higher-than-average skewed degree distribution (ie people have a lot of friends), will tend to be more stable (ie be more resilient to the k-core test), have shorter paths (on average) and therefore a smaller diameter, will be clustered more, and have higher betweenness centrality. 

This is really nerdy stuff... 

1 comment:

Bryan Hurren said...

harvest, how is idiro different than pajek?