Monitoring dynamic spatial fields using responsive geosensor networks

Abstract

Information about dynamic spatial fields, such as temperature, windspeed, or the concentration of gas pollutant in the air, is important for many environmental applications. At the same time, the development of geosensor networks (wirelessly communicating, sensor-enabled small computing devices, distributed throughout a geographic environment) present new opportunities for monitoring of dynamic spatial fields in much more detail than ever before. This paper presents a new model for querying information about dynamic spatial fields using geosensor networks. In order to manage the inherent complexity of dynamic geographic phenomena, our approach in this paper is to focus on the qualitative representation of spatial entities, like regions, boundaries, and holes, and of events, like splitting, merging, appearance, and disappearance events. Based on combinatorial maps, we present a qualitative model as the underlying data management paradigm for geosensor networks that is capable of tracking salient changes in the network in a much more energy-efficient way. Further, our model enables reconfiguration of the communication in the geosensor network in response to changes in the environment. We present an algorithm capable of adapting sensor network granularity according to dynamic monitoring requirements. Regions of high variability can trigger increases in the geosensor network granularity, leading to more detailed information about the dynamic field. Conversely, regions of stability can trigger a coarsening of the sensor network, leading to efficiency increases in particular with respect to power consumption and longevity of the sensor nodes. Querying of this responsive geosensor network is also considered, and the paper concludes with a review of future research directions.