Directed Scale-Free Networks

A subset of Scale-Free Networks, used for example by terrorist networks.

Description

From a discussion in the Global Guerrillas blog, concerning the paper Embodying Terror Networks: How Direction Creates Structure by Mitch Stripling.

Comment from http://globalguerrillas.typepad.com/globalguerrillas/2007/02/terrorist_netwo.html:

"Terrorist networks aren't merely generic scale-free networks, but more likely an important subset: directional scale-free networks. Scale-free networks are typically depicted by a set of nodes that are symmetrically connected (I link to you, you link to me). The dynamic flows that travel through those networks, whether they be information/fluids/electricity/contagion, can travel in both directions across symmetric links. However, that doesn't actually happen in many real world networks. In these networks, links have direction (I link to a major hub, and it doesn't link back to me). Directional networks, in contrast, have links that are asymmetric and offer only unidirectional flows.

When you apply the directional scale-free network model to al Qaeda, you see a fairly good fit, particularly when you assume that the al Qaeda of today is more of a movement than a cohesive organization (Mitch provides some historical analysis to back this up)."

More Information

Paper by Mitch Stripling at http://www.crisisville.com/files/Terrorism-DirectedNetworks.pdf

Terrorism and scale-free networks at http://globalguerrillas.typepad.com/globalguerrillas/2004/05/scalefree_terro.html