STEVE INSKEEP, host:
And as we wait to hear more about the president's visit, let's talk about this. Members of the military have found a new approach, they think, to the problem of roadside bombs. It involves math. Math is a weapon in the war in Afghanistan, as well as in Iraq. They use mathematical models to identify a network of individuals who make and place bombs.
NPR's Tom Gjelten went to Fort Bragg in North Carolina to learn more.
TOM GJELTEN: The idea here is that a roadside bomb is never the work of one individual alone.
Professor KATHLEEN CARLEY (Carnegie-Mellon University): Someone has to build it. Someone has to place it. Someone has to do surveillance on the place where you place it.
GJELTEN: Kathleen Carley, a professor of computer science at Carnegie-Mellon University, is the godmother of social network analysis as applied to the IED problem.
Prof. CARLEY: And if you're trying to defeat IEDs, what you're talking about is understanding that whole process - who is involved, how they're connected to each other - so that you can figure out where the best place is to intervene.
GJELTEN: In other words, if you're going to capture or kill one person in the IED network, who should it be to have the best chance of bringing the whole operation down? The answer may be found in mathematics. And at Fort Bragg, North Carolina, soldiers en route to Iraq are getting a crash course.
Major IAN MCCULLOH (United States Army): So now you can do the relational algebra to have people associated by their common event, their common knowledge, or their common resource.
GJELTEN: Army Major Ian McCulloh got his PhD at Carnegie Mellon, under Professor Carley. He's teaching this network analysis and targeting class at Fort Bragg while on leave from his job as deputy director of counter-IED operations in Baghdad.
The students are visualizing a network of all the people involved in an IED cell. On a computer screen, each one is a node, displayed as a dot linked by lines to other dots. Some individuals are more important than others, depending on their centrality score - basically how connected they are to others in the IED network.
Major MCCULLOH: You know, from these guys to these guys, it's a lot shorter to go through D than it is to go through E and F to get there, so that's what kind of gives D a high betweenness centrality. He's also connected to the most people. He also has an average shorter distance to everybody. So in many ways D is the highly central node.
GJELTEN: When the U.S. military is looking for key people to capture or kill, you do not want them to identify you as a highly central node. All the soldiers in Major McCulloh's class will have some role in the anti-IED effort in Iraq. Major Robert Cope will be at the headquarters of the 18th Airborne Corps.
Major ROBERT COPE (U.S. Army): I'll be the counter-IED lead on the USFI staff.
GJELTEN: That's United States Forces Iraq.
Major COPE: And I'll be involved in the targeting. So this is - this will very much complement my tool kit.
GJELTEN: In truth, intelligence analysts have long understood the need to study enemy relationships. What's new is how sophisticated the process has become. Veteran analysts use hunches and intuition to construct the social network that lies behind a roadside bombing operation. But brainy warrior-mathematicians like Major McCulloh can do it far more quickly.
Major MCCULLOH: The first network I looked at probably had about two to three hundred nodes in it, and it took an analyst with 26 years experience about five days to look through it and identify where they felt the key vulnerabilities were, and I was able to put it into the software that I'm using and do some basic network analysis, and in about 15 to 20 minutes I kind of had the same conclusion.
GJELTEN: As with any computer operation, the quality of the analysis depends on the quality of the data going in. Kathleen Carley, who's worked with the military since she got out of college, says if soldiers are to understand a roadside bombing network, they need information, from people they capture, from informants, from intercepted phone calls.
Prof. CARLEY: You try to find things out about who else they know, who they're related to, where they've been in the past, where were they trained, what other kind of groups did they belong to, things like that.
GJELTEN: But here's another advantage of network analysis: A computer-generated network diagram can help soldiers see what other terrorist data they need to go after. Finally, the mathematical precision that comes with this analysis gives soldiers extra confidence in their judgments. That's important to military lawyers who have to approve an operation to capture or kill someone.
Major Eugene Vindman, a JAG officer, or judge advocate general, says he's taking Major McCulloh's network analysis course because it'll be better prepare him for his oversight responsibilities in Iraq.
Major EUGENE VINDMAN (JAG Officer): Maybe do a little bit of analysis on your own or ask some intelligent questions of the targeteer, to make sure that the target they've identified is not a guy that might have made a wrong phone call to a bad guy but actually has enough links to that bad guy through other activities to actually be a bad guy and therefore be a legal military target.
GJELTEN: The military's biggest success so far in the use of network analysis was the capture of Saddam Hussein in 2003. He was found after soldiers diagrammed the social networks of his chauffeurs and others close to him. The technique is now used extensively to identify the key figures in an insurgent group. And in both Iraq and Afghanistan, attack the network is the motto of the anti-IED effort.
Tom Gjelten, NPR News.