CSR: Small: Maintaining System Operation in Wireless Sensor Networks Over Long Lifetimes

University Of Virginia Main Campus, Charlottesville VA

Investigators

Abstract

Wireless sensor network technology is being considered for many real world applications that require high reliability and long lifetimes. For example, new, low cost wireless sensor networks (WSN) can be embedded into large city skyscrapers to support fire detection and reaction. Such systems must reliably detect a fire on any floor, activate alarms, notify fire stations, and announce and illuminate egress routes. These buildings are passively monitored for hazards and are largely unattended. However, such systems require high confidence in their operation and must also be able to demonstrate that they are operational on a periodic inspection basis (at a minimum). This project determines how to specify and support, at runtime, a collection of solutions that enable embedded systems to improve confidence and demonstrate application operability. The project is novel in several ways. First, it develops a requirements language that permits designers to specify, via a combination of declarative statements, invariants, and rules, the runtime assurances required for high confidence. The language addresses application semantics, the statistical nature of WSN, costs, future predictions on system performance, and monitoring needs for various mechanisms. It also permits automatic code generation. Second, a runtime assurance methodology and framework is developed that supports specific demonstrations of a system?s key functional capabilities on demand and offers a well defined set of diagnosis capabilities including data mining when the system fails to meet its assurances. Third, various runtime mechanisms are created and used in novel ways including virtual event generation and real event replay. Fourth, as a system evolves solutions for understanding the system model as applied to controller design are developed. Fifth, an implementation and evaluation in an application domain is undertaken. Broad impact of the work is possible because similar issues exist for WSN applications in industrial plants, home and assisted living health care, and transportation. A set of course modules is developed and incorporated into two current course offerings at the University of Virginia: Wireless Sensor Networks and Cyber Physical Systems. The corresponding teaching materials (slides and labs) are available for use at other Universities via the Web. The School of Engineering Office of Minority Affairs is used to match minority students with this research.