Virtual Sensors and Actuators

mica2 Recent trends in wireless sensor network (WSN) applications exhibit increasing degrees of decentralization. This is particularly true of scenarios where the data reported by sensors is used to control actuators affecting the environment. Implementing this control loop in a decentralized fashion is much more complex than in mainstream, single-sink, sense-only applications.

Virtual sensors and actuators are a programming abstraction simplifying the development of decentralized WSN applications. The data acquired by a set of sensors can be collected, processed according to an application-provided aggregation function, and then perceived as the reading of a single virtual sensor. Dually, a virtual actuator provides a single entry point for distributing commands to a set of real actuator nodes. The set of physical nodes to be abstracted into a virtual one is specified using Logical Neighborhoods. Using virtual nodes, the programmer focuses on the application logic, rather than on low-level implementation details.

The flow of information between real devices and virtual sensors or actuators. Nodes belonging to the same logical neighborhood are identified with the same dashed lines.

The following publications provide further details on the programming abstraction and supporting run-time: