Networked Infomechanical Systems (NIMS): Next Generation Sensor Networks for Environmental Monitoring Richard Pon 1,2 , Aman Kansal 1,2 , Duo Liu 1,2 , Mohammad Rahimi 1,3 , Lisa Shirachi 1,2 , William J. Kaiser 1,2 , Gregory J. Pottie 1,2 , Mani Srivastava 1,2 , Gaurav Sukhatme 1,3 , Deborah Estrin 1,4 1 Center for Embedded Networked Sensing, University of California, Los Angeles, CA 90095 2 Electrical Engineering Department, University of California, Los Angeles, CA 90095 3 Computer Science Department, University of Southern California, Los Angeles, CA 4 Computer Science Department, University of California, Los Angeles, CA 90095 Abstract — Embedded networked sensing systems have been successfully applied to environmental monitoring in a wide range of applications. These first results have demonstrated a potential for advancing fundamental environmental science methods and environmental management capability as well as for providing future methods for safeguarding public health. While substantial progress in sensor network performance has appeared, new challenges have also emerged. Specifically, the inevitable and unpredictable time evolution of environmental phenomena introduces sensing uncertainty and degrades the performance of event detection, environment characterization, and sensor fusion. Many of the physical obstacles encountered by static sensors may be circumvented by a new method, Networked Infomechanical Systems (NIMS). NIMS integrates distributed, embedded sensing and computing systems with infrastructure-supported mobility to enable direct uncertainty characterization, autonomous adjustment of spatiotemporal sampling rate, and active sensor fusion. NIMS actuation is also being applied to advancing sensor network performance through methods based on control of distributed, directional antenna systems. In addition to advances in fundamental research objectives, this presentation will describe the architecture, implementation, and application of NIMS now deployed and continuously operating in the field... Index Terms — Wireless networked sensors, mobile wireless networking. I. INTRODUCTION Wireless embedded networked sensing (ENS) systems have been successfully applied to environmental monitoring in a wide range of applications.[1] These first results have demonstrated a potential for advancing fundamental environmental science and environmental management capability as well as providing future methods for safeguarding public health. The primary challenges for operation of networked embedded sensing systems first appeared in the development of scalable, low energy and self- organized networked sensing. Progress in solving these critical problems has enabled deployments of networked sensor systems. However, the applications for embedded networked sensing have revealed yet new challenges associated with either detecting events or characterizing field variables in the complex environments of greatest interest. This presentation will describe these problems in sensing and additional challenges that are encountered as well in sensor deployment, energy management, and finally in essential wireless networking capabilities. A new solution to these problems, Networked Infomechanical Systems (NIMS) based on infrastructure- supported mobility will be described. NIMS introduces a new networked embedded system capability that provides the ability to explore large volumes, adds new networking flexibility and functionality, and new logistics for support of distributed sensors, as well as the capability for self- awareness. This requires, in turn, the development of new methods for scalable and optimized coordination of mobility among nodes for many possible objectives. NIMS infrastructure-supported mobility also enable low energy transport and retain inherent low operating energy, rapid deployment characteristics, and environmental compatibility of distributed sensors. Together, these features offer a dramatic expansion in available design options for networked sensors. This presentation will particularly focus on specific ENS design requirements and limitations. This includes discussion of the verification of the hypothesis that NIMS constrained actuation methods resolve these limitations. The recent development and deployment of NIMS and additional new challenges that lie ahead will also be described. II. ENVIRONMENTAL MONITORING BY DISTRIBUTED NETWORKED SENSING:STATIC AND ACTUATED SENSING A wide range of important environmental monitoring applications may take advantage of the capabilities of networked sensing for matching the spatially distributed nature of phenomena with similarly distributed sensors. At the same time, environmental monitoring requirements present unique design challenges for networked sensing that have not been solved with conventional sensor network deployments. Thus, actuated sensing devices carrying the capability for physical reconfiguration must be introduced. The specific design requirements and associated applications of actuation and actuated sensor systems are discussed below. 1) Sensing Uncertainty: As ENS systems are deployed in increasingly important applications; there are increasingly severe requirements for reducing the uncertainty associated with sensing phenomena and detecting events. This uncertainty depends not only on the sensing element characteristics, but, also the propagation environment for sensors to view signal sources. The physical configuration 0-7803-8846-1/05/$20.00 (C) 2005 IEEE 373