To the untrained eye, the sleek, airy building constructed atop a decommissioned nuclear reactor at the University of California, Los Angeles could pass for high-tech office space.
A closer inspection of the glass-and-steel facade reveals dozens of miniature, low-resolution cameras and sensors. They're wirelessly linked to computers throughout the 6,000-square-foot space, keeping tabs on traffic flow in public areas and monitoring temperature, humidity and acoustics.
The building serves as a testing ground for developing and perfecting wireless sensing technology to connect major chunks of the real world to the Internet. Such networks could monitor the environment for pollutants, gauge whether structures are at risk of collapse or remotely follow medical patients in real time.
"I see this as the next wave of extending the Internet into the physical world," said computer scientist Deborah Estrin, who heads the Center for Embedded Networked Sensing, a UCLA-based consortium of six schools.
The researchers at the consortium have already scattered wireless networks of nodes in the rice paddies of Bangladesh, rain forests of Costa Rica and wilderness of California's San Jacinto Mountains — all for the sake of keeping a closer eye on the world.
Once the stuff of science fiction, wireless sensor networking is quickly catching on, attracting the attention of the military, academics and corporations. Just as the Internet virtually connected people with personal computers, the prospect of wireless arrays sprinkled in buildings, farmland, forests and hospitals promise to create unprecedented links between people and physical locations.
Advances in miniaturization and integration of hardware have enabled the design of smart sensor nodes ranging from a square inch to the size of a matchbox.
However, the rush to cram tiny cameras into the nooks and crannies of daily life raises security and privacy concerns among some observers who fear rogues could hack into the networks. Corporations are beefing up safeguards, and academics are studying privacy pitfalls and trying to build stronger networks to protect against security breaches.
The commercial possibilities have already spawned a cottage industry of startups intent on developing cheap, reliable wireless nodes. Several of the ventures, including Dust Networks and Arch Rock Corp., have connections to the University of California, Berkeley, which was involved in early efforts to develop "smart dust" or sensors the size of dust that could be sprinkled in hard-to-reach places.
Today, the technology is primarily used to monitor pipelines and to control climate conditions inside factories. Demand for more uses in the home, agriculture and health care could push the market from several hundred million dollars currently to $8 billion worldwide by 2010, according to San Diego-based wireless market research firm ON World.
That growth has been slowed by compatibility issues, with many sensors now custom-made for specific tasks. The ZigBee Alliance, comprised of more than 150 companies, is developing rules to make networks interoperable, but a universal standard is still years away.
Wireless nodes, or motes, are made up of microprocessors, sensors and low-radio radio transceivers to communicate to the outside world. The capability of the sensors varies and can measure temperature, light, stress or other conditions.
Motes are usually densely packed in an environment _ like a vineyard or waterway _ to monitor the surroundings. Most are battery-powered, while smaller versions are solar-powered. The cost ranges from $20 to several hundred dollars, depending on the type of sensors.
As with any wireless technology, sensor networks can be prone to malicious security attacks or illegal eavesdropping, said Adrian Perrig, an assistant professor of electrical and computer engineering at Carnegie Mellon University. He has written extensively about security and privacy hurdles of wireless sensor communication and is working to create more secure networks.
"If poorly secured networks are deployed and exploited, people may have significant concerns about sensor technology," he said.
Research at the UCLA building, which opened last year, is funded by the National Science Foundation, which committed $40 million over 10 years for the center. The building serves as a central hub for scientists in various fields of wireless sensor networking to work under one roof.
A sign posted in the lobby makes it clear the space is not private: "Research in progress. Electronic sensing and monitoring devices in use within this space, including cameras and microphones."
"These are not toy systems," said John Cozzens, a program director at the foundation.
Researchers labor behind white cubicles analyzing data spit back by wireless sensors nestled in the real world.
One of the fields where researchers believe wireless sensor technology could be commonplace is in the health care setting.
Graduate student Sasank Reddy is working on a project to determine if it's better to measure caloric intake by toting around a cell phone camera and taking pictures at mealtime or self-reporting eating habits on a standard dietary questionnaire.
He recently hung a primitive mote around his neck — actually, a camera phone — as he lunched. The camera snapped away every 10 seconds as he nibbled on his Italian sub.
Later, as he browsed through the images on his work computer, Reddy saw some red flags and determined the technique wasn't ready for prime-time: Some pictures came out too blurry. Others showed the faces of fellow diners in the background, raising privacy issues.
"I get a ton of information about what I'm eating, but there are data that shouldn't be shared," he said.