A demonstration of wireless sensing for long-term monitoring of water quality

At a time when technological advances are providing new sensor capabilities, novel network capabilities, long-range communications technologies and data interpreting and delivery formats via the World Wide Web, we never before had such opportunities to sense and analyse the environment around us. However, the challenges exist. While measurement and detection of environmental pollutants can be successful under laboratory-controlled conditions, continuous in-situ monitoring remains one of the most challenging aspects of environmental sensing. This paper describes the development and test of a multi-sensor heterogeneous real-time water monitoring system. A multi-sensor system was deployed in the River Lee, County Cork, Ireland to monitor water quality parameters such as pH, temperature, conductivity, turbidity and dissolved oxygen. The R. Lee comprises of a tidal water system that provides an interesting test site to monitor. The multi-sensor system set-up is described and results of the sensor deployment and the various challenges are discussed.

Untangling unstructured programs

A method is presented for converting unstructured program schemas to strictly equivalent structured form. The predicates of the original schema are left intact with structuring being achieved by the duplication of he original decision vertices without the introduction of compound predicate expressions, or where possible by function duplication alone. It is shown that structured schemas must have at least as many decision vertices as the original unstructured schema, and must have more when the original schema contains branches out of decision constructs. The structuring method allows the complete avoidance of function duplication, but only at the expense of decision vertex duplication. It is shown that structured schemas have greater space-time requirements in general than their equivalent optimal unstructured counterparts and at best have the same requirements.