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SECURITY TECHNOLOGIES OVERVIEW 6 packaging), communications (energy-efficient miniature radios; energy-aware, ad-hoc networking), processing (power conservation; sensor and data fusion), and node location and orientation. Kolodny believes that many of the enabling technologies already exist, but the systems will have to be made smaller and less expensive, and all the elements of nodes will need to be integrated up front for a successful network. PANEL 1 DISCUSSION In response to a question about whether the enabling technologies already exist for unattended ground sensor networks described by Kolodny, he stated that the basic performance capabilities of individual pieces (e.g., sensors) are good enough if we can fuse the data and make them smaller and cheaper. One comment, however, was that as we go to smaller and smaller length scales, we may have to take an entirely different technological approach. The Army has specified a cost of no more than $10 per node, including communications, and is focusing on the commercial sector because it is interested in production runs on the order of 10 million units. On a small scale, there are commercial drivers for multiplexed sensors, such as sensors for tracking the location of products (e.g., laptops) within a building. Asked whether any self-assembled networks are currently available, Kolodny mentioned Millennia Net in Boston, as well as Smart Dust, Inc.'s Motes. He emphasized that the nodes must be emplaceable and mobile (e.g., wearable). Emplaceable does not necessarily mean stationary (they could be on wheels or wings); as forces engage, it might be desirable to move them. They should have a 75-km range and when used in caves may be deployed on microrobots. Mobile sensors today are not networked. If we wanted to tag an entire regiment rather than an individual soldier, how would the data be processed? High-capability nodes today have 32-bit floating point arithmetic processors, while less capable nodes have 8-bit processors. Companies are currently using radio frequency identification (RFID) tags to sense environmental conditions and track shipped material. (Temperature and humidity changes during shipping can cause a product to degrade, which can reflect poorly on the manufacturer.) Asked about the lifetime of sensors, Jotcham noted that passive sensors have essentially an infinite life, while the life of active sensors can be extended if one programs them to send out intermittent transmissions of information. For many military missions, a lifetime of at least 72 hours is desired, and all kinds of power conservation techniques are used. Where lifetimes of one month or so are required, one could spread the tags over a large group and activate them individually (e.g., with a laser) from a distance. This approach is being evaluated with RF tags. Organic electronics is one way to create cheap tags. Plastic chips are now available, and there is a great deal of research going on. The Army is looking 6 years out for deployment and hopes that advances in nanotechnology will provide a low-cost system on a chip. On the cost issue, it was noted that all of the examples given thus far appeared to describe a heterogeneous group of tags with unique characteristics. For an integrated national system of tags with standard capabilities, the panelists believed that commercial companies would likely favor any approach that reduced costs, as occurred with the existing bar coding system. Kolodny was asked whether there had been any real progress in unattended ground sensors recently. He responded the track record was poor. Essentially, there has been no progress since the 1970s. There are fieldable systems, but they are not used because they are too expensive (>$8,000 per node) and not easily deployable. With the Army shifting its focus to warfare in urban environments, deployable, cheap nodes are needed that can be fielded in the next 6 years.
