Neural Networks

The power and usefulness of neural networks is demonstrated by the success of the TNA (Thermal Neutron Analysis) project, developed by SAIC (Science Applications International Corp.). TNA is a neural-network-based machine used at airports that detects and classifies any explosives that might be present in a traveler's luggage, by directing neutron radiation at it and analyzing the neutron profile. Originally, SAIC had used a conventional method, the linear discriminant technique, to classify the explosives. But it proved to be inefficient and slow, since the luggage had to be grouped by size and the machine set for that size. With the deadline looming for its FAA contract, SAIC resorted to neural networks, accomplishing the classification by the use of a backpropagation network; the result was faster, more efficient categorization and on-time delivery [Shea and Lin 19891.