3Qs: Homeland security, 10 years after 9/11

Photo by Craig Bailey.

Nearly 10 years have passed since the terrorist attacks of Sept. 11, 2001, transformed the world forever and reshaped America’s views on many aspects of life, including national defense. At Northeastern University, researchers are conducting groundbreaking work in areas such as explosives detection, cyber defense, robotics and data security. We asked Michael Silevitch, co-director of ALERT (Awareness and Localization of Explosives-Related Threats), a multi-university Department of Homeland Security Center of Excellence, to elaborate on the University’s innovative security research.

How did 9/11 change the nation’s perception of homeland security?

Clearly, before the event, we as a country felt fairly secure and relatively impregnable in terms of the issues of foreign terrorism. Since 9/11, it’s been very clear we are engaged in a worldwide struggle, not just overseas but one that has a direct impact on our national security. The Department of Homeland Security has been formed and developed at a fairly rapid pace. We now have an infrastructure within the country for homeland security to deal with attacks within our borders.

How far have we come as a nation, and what challenges remain?

My own expertise is in explosive detection, mitigation and response, which is the theme of our ALERT Center. Within that domain, there are several grand challenges, including whether we can achieve unequivocal reliability in screening passengers and luggage at airports for explosives and other threats. We’ve made progress in enhancing the performance of devices and methods to screen people with better reliability and lower the false alarm rate. On the other hand, terrorists are designing the threats of tomorrow, such as homemade explosives. We need to maintain the specificity of the screening equipment that will allow screeners to keep abreast of the new compounds that need to be sifted.

A second grand challenge is identifying a threat a football field away. In places where there is no gateway to the event, can you scan crowds with technology to determine whether something is threatening or non-threatening? That is one of the main areas of our research, in terms of devices like radar equipment that will beam electromagnetic radiation at a potential subject to see if a signal correlates to metal being carried — like a suicide bomber’s vest or an anomalous shape. Video analytics in screening crowds for anomalous behavior is another area of interest.

We’re also focusing on pre- and post-blast mitigation — detecting the presence of an explosive and somehow minimizing the impact of the blast beforehand or protecting ourselves more effectively against shrapnel and collapsed buildings.

What are the latest projects you and your colleagues are working on at the ALERT Center?

In the area of highly reliable screening, we’re working on technologies that will do a better job of imaging inside of carry-on and checked bags, using advanced reconstruction algorithms, computer tomography and x-ray technology. We’re looking at ways of minimizing the burden on the equipment operators, because they screen many pieces of luggage continually and we want to aid them with more flags to look into.
Another area of interest is the screening of passengers at an airport portal. We’re looking to make that a more reliable process to introduce multiple sensors that act together.

We’re also looking at some fundamental research in the nature of explosives themselves. What makes a material become explosive? How does it form at the nanoscale? There are a lot of interesting physics and chemistry processes that are going on in that small scale, in terms of such things as hotspots forming within the material. We’re also looking at designing blast resistant materials that mimic effective structures that occur in nature.