Adaptive self-configuring
systems

The sheer number of distributed elements in these systems precludes dependence on manual configuration. Furthermore, the environmental dynamics to which these elements must adapt prevents design-time pre-configuration of these systems. Thus, realistic deployments of these unattended networks must self-reconfigure in response to node failure or incremental addition of nodes, and must adapt to changing environmental conditions. If we are to exploit the power of densely distributed sensing, these techniques for adaptation and self-configuration must scale to the anticipated sizes of these deployments. In recent years, some work has begun to allow networks of wireless nodes to discover their neighbors, acquire synchronism, and form efficient routes [Pottie-Kaiser00]. However, this nascent research has not yet addressed many fundamental issues in adaptively self-configuring the more complex sensing and actuation systems described here, particularly those arising from deploying embedded systems in real-world, environmentally-challenging contexts [Estrin-et.al.99]

Driven by our experimental domains, we are using this experimental platform to develop techniques for self-configuration:

• Integrated techniques for self-assembly and self-healing in these deeply distributed systems. These methods should enable self-configuration--both at the lower-level communication layers in addition to higher levels such as distributed name spaces.

• Simple localized algorithms that effect coordinated data collection and processing to achieve measurement aggregation or higher-level alert generation [Abelson99]. Preliminary research indicates that a particular paradigm for network organization, directed diffusion [Intanago-et.al.00], can efficiently achieve such coordination and resource allocation needs, but considerable experimentation and modeling work is still required.

• Protocol and system level techniques that enable energy-efficiency beyond what is feasible with low-power component design alone. Such techniques, designed for robust operation, can achieve system longevity without sacrificing vigilance.

• Techniques for time synchronization and localization in support of coordinated monitoring. At the target node scales, relying on global positioning systems alone may not be appropriate.

• In some contexts the ability of the node to move itself (or selected appendages), or to otherwise influence its location will be critical. Distributed robotics [Mataric95] in a constrained context will greatly extend the capabilities of these systems. Benefits of including self-mobilizing elements [Sukhatme99] are: self-configuring systems to adapt to realities of an inaccessible terrain, developing a robotic ecology for delivering energy sources to other system elements, and obtaining coverage of a larger area.