"It is a proven fact that [randomization methodology] increases security."

Since there's supposed to be safety in numbers, airport security officials at Los Angeles International Airport are betting there is also security in numbers, so long as the numbers are random.

At least that's the idea behind a new security scheme, based on game theory, that was implemented last August at LAX.

Traffic backs up at a vehicle checkpoint at Los Angeles International Airport in Los Angeles, June 30, 2007. (AP Photo/Dan Steinberg)

The system, called ARMOR (Assistant for Randomized Monitoring over Routes), provides an intelligent, computerized approach to randomizing patrols and checkpoint locations. Randomizing solves the problem of limited resources; it's generally impossible to provide saturation security coverage around the clock for most facilities.

"Adversaries can observe security arrangements over time and exploit any predictable patterns to their advantage," said University of Southern California computer science professor Milind Tambe. "Randomizing schedules for patrolling, checking or monitoring is thus an important tool in the police arsenal to avoid the vulnerability that results from predictability."

ARMOR provides security with airtight unpredictability. Its randomizing schemes are performed by sophisticated algorithms developed by Tambe's group at the Center for Risk and Economic Analysis of Terrorism Events (CREATE), a DHS Center of Excellence based at USC.

Tambe told Homeland1 that ARMOR is unique in that it has taken a novel game-solving algorithm and turned it into a practical solution to better secure LAX.

"This marriage of theory and practice is what is tremendously exciting and unique about ARMOR from an academic perspective," Tambe said. "Practical application feeds new research problems, and new research improves practical applications."

ARMOR recently completed a six-month trial and is now in routine use at LAX, the fifth-busiest airport in the world.

"It is a proven fact that randomness increases security," said Erroll Southers, chief of homeland security and intelligence for LAX's parent organization, Los Angeles World Airports. Southers, who is also CREATE's associate director, first brought LAX police officials and the USC academics together.

"When I arrived at LAX, I became aware of the vehicle checkpoints and the need to randomize their deployment," Southers said.

Southers said randomization methodology was first proposed by CREATE to assist in the deployment strategy of unmanned aerial vehicle flights over Afghanistan.

"The al-Qaeda planning cycle depends on comprehensive situational awareness acquired via pre-attack surveillance and reconnaissance of intended targets," Southers told the Congressional Committee on Homeland Security in May. Unpredictability is therefore essential.

"The goal of the ARMOR project at LAX was to leverage CREATE's success by randomizing vehicle checkpoints deployed along airport access roads," Southers said.

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