UCLA Researchers Develop Wireless Mobile Sensing System for Enriched Monitoring of the Environment By Marlys Amundson and Christopher Sutton At the University of California’s James San Jacinto Mountains Reserve, researchers have deployed a robot to patrol the forest canopy, looking for subtle changes in temperature, humidity or sunlight. Moving along cables attached to the trees, and equipped with an array of sensors, the robotic technology, known as networked infomechanical systems (NIMS), can be used to monitor a mountain stream ecosystem from the ground to the treetops for global change indicators, or observe coastal wetlands and urban rivers for biological pathogens. The same technologies could one day be applied to securing and monitoring public spaces such as ports and bridges. The five-year project, which began in 2003, will receive $7.5 million from the National Science Foundation (NSF) through an Information Technology Research grant. The project includes researchers from the University of California, Los Angeles, University of California, Riverside, University of California, Merced, and the University of Southern California. The project leader is Bill Kaiser, an electrical engineering professor in the UCLA Henry Samueli School of Engineering and Applied Science. "The forest canopy houses about 40 percent of earth’s species, and it is where most of the interaction between the atmosphere and all biomass occurs," said Kaiser. "This technology is important because ultimately we are interested in knowing to what degree our global activity is affecting the environment." According to Michael Hamilton, James Reserve director and assistant professor of Conservation Biology at UC Riverside, NIMS will dramatically enhance the range of variables being measured within the complex plant communities and wildlife habitats of the James Reserve. “This is a breakthrough in the same sense that the telescope was a breakthrough in astronomy,” said Hamilton. “I see this technology doing the same thing for ecology and environmental sciences. It will completely change the way we conduct our science.” The NIMS robot, dubbed the Treebot because of its use within the forest canopy, is equipped with environmental sensors, a camera, a server and a wireless Internet link. The robot travels along a collection of steel cables, each attached to any two points - buildings, trees, or other natural structures - that serve as suspension points. Sensors, which can be lowered or elevated, collect data on temperature, humidity, wind speed, rainfall, and soil moisture, among other things. The Treebot then transmits the data directly to researchers’ desktops. The robot can also dock when necessary to recharge its energy source, removing energy constraints that have limited other remote wireless sensor networks in the past. According to Kaiser, NIMS addresses long-standing problems with current wireless sensor network technology, including energy constraints, sustainability, and sensing uncertainty due to obstruction by physical objects in a real-world environment. “What NIMS offers that we didn’t have before is the ability to probe at every point and every depth,” said Kaiser. “The system allows us to introduce the physical reconfiguration that is necessary for adapting physical sensors. We can add new sensors and move sensors in such a way as to allow us to actually measure and actively reduce sensing uncertainty.” NIMS offers researchers other new capabilities as well. “NIMS devices can collect and transport physical samples from the environment, which means researchers are no longer limited to sensing only with in-situ devices,” said Kaiser. “We also plan to exploit NIMS’ ability to replace, relocate, and replenish fixed nodes.” Electrical engineering professor Greg Pottie’s research on the project examines how to systematically characterize the reduction in uncertainty that results from the use of mobile and articulated sensors. Last summer, several undergraduate students assisted him with the sensor diversity problem, helping determine how multiple views of the same environment can improve certainty in obstructed environments. “We’ve been fortunate to have this NSF funding for the formation of a robotic sensor system that provides sustained observation for basic environmental science and public health concerns,” said Pottie. The project is part of the Center for Embedded Networked Sensing, where researchers are developing embedded networked sensing systems and applying this revolutionary technology to critical scientific and social applications. Like the Internet, these large-scale, distributed systems, composed of smart sensors and actuators embedded in the physical world, will eventually infuse the entire world, but at a physical level instead of virtual. “What NIMS brings to CENS is both figuratively and literally a couple of new dimensions,” said Deborah Estrin, CENS director and a computer science professor in UCLA’s School of Engineering. “We've been looking at problems in which sensors are placed in two-dimensional space. NIMS - elevated above the surface - offers three-dimensional sensing solutions.” The NIMS team draws on the expertise of researchers at several top-tier universities in Southern California. Gaurav Sukhatme, director of the Robotic Embedded Systems Laboratory at USC, is interested in multi-robot systems and how robots can coordinate their activity as a team to perform a task efficiently. “The sensor system requires a degree of autonomy - not only to reduce the amount of oversight required, but also because the operator doesn’t necessarily know where to look,” said Sukhatme. “If coordination isn’t done well, all of the nodes could end up in one location and entirely miss other items of interest in another part of the ecosystem.” Embedded sensor systems promise to open up a host of new research opportunities in public health applications and in the natural environment. Sensors could be used to signal when a building is safe to reenter after a quake; sensors scattered on the forest floor can predict a fire’s path; and sensors can be used to monitor the presence of radiation or toxic chemicals in the air. UCLA researchers intend to create a NIMS infrastructure that can be adapted by other researchers to suit their applications. “Too often, we cannot address important research questions because of our inability to sample the right thing at the right time and place,” said Richard Ambrose, director of the UCLA Environmental Science and Engineering Program. According to Ambrose, NIMS has the potential to enable continuous, sustainable monitoring of coastal water zones, collecting data on critical pathogen sources and how water system dynamics affect the fate of pathogens. Current monitoring efforts rely on manual sampling taken at intermittent intervals. The NIMS team completed a test installation at the Wind River Canopy Crane Research Facility in Washington this summer. Kaiser and a group of students rode in the gondola of a large crane to suspend cables, solar panels, and an aerial sensor between two trees approximately 150 feet above the forest floor. “Researchers will be looking at the complexity of an old growth stage within the canopy,” said Ken Bible, research coordinator at Wind River. “A lot of what they’ll be monitoring is basic forest ecology - for instance, using infrared imagers to track forest temperatures and heat patterns. NIMS’ embedded sensor design will provide practical information to the researchers, who will need to find ways to distill it for the policy makers and managers.” The CENS team hopes to extend the work to sites in other areas, such as the La Selva Biological Station in Costa Rica. Philip Rundel, a professor in the UCLA Department of Organismic Biology, Ecology, and Evolution, and a founding faculty member with CENS, explained, “NIMS will allow us to collect spatially and temporally dense measurements across the forest floor and canopy - information that is vital to understanding the impact of the environment on the diversity of species in the rain forest.”