Title: An Ontology for Sensor Networks
Citation: Geophysical Research Abstracts vol. 12
Publisher: Copernicus
Publication Year: 2010
JRC N°: JRC56579
ISSN: 1607-7962
URI: http://www.geophys-res-abstr.net
Type: Articles in periodicals and books
Abstract: Sensors and networks of sensors are important ways of monitoring and digitising reality. As the number and size of sensor networks grows, so too does the amount of data collected and the complexity of the networks as sensing instruments. Users of such networks typically need to discover the sensors and data that ¿t their needs without necessarily understanding the complexities of the network itself. The burden on users is eased if the network and its data are expressed in terms of concepts familiar to the users and their job functions, rather than in terms of the network or how it was designed. Furthermore, the task of collecting and combining data from multiple sensor networks is made easier if metadata about the data and the networks is stored in a format that is amenable to machine reasoning and inference. While the OGC¿s (Open Geospatial Consortium) SWE (Sensor Web Enablement) standards allow the description, cataloguing and access of data and metadata for sensors, they do not provide facilities for abstraction, categorisation and reasoning consistent with standard technologies. The latter can aid in developing networks that are easier to manage and query. Once sensors and networks are described using semantics (that is, by using logic to describe the sensors, the domain of interest and the measurements) then reasoning and classi¿cation can be used to analyse and categorise data, relate measurements with similar meaning or information content, and organise, query and task sensors. This will enable types of automated processing and logical assurance that can extend the OGC standards. The W3C SSN-XG (Semantic Sensor Networks Incubator Group) is producing a generic ontology to describe sensors, their environment and the measurements they make. The ontology provides definitions for the structure of sensors and observations, leaving the observed domain unspecified, to be supplied in the application. This allows abstract representations of real world entities, which are not observed directly but through their observable qualities. Domain semantics, units of measurement, time and time series, and location and mobility ontologies can be easily attached when instantiating the ontology for any particular sensors in a domain. After a review of previous work on the specification of sensors the group is developing the ontology in conjunction with use case development. Part of the difficulty of such work is that relevant concepts from for example OGC standards and other ontologies must be identified and aligned and also placed in a consistent and logically correct way into the ontology. In terms of alignment with OGC¿s SWE, the ontology is intended to be able to model concepts from SensorML and O&M. Similar to SensorML and O&M, the ontology is based around concepts of systems, process, sensors and observations. It supports the description of the physical and processing structure of sensors. Sensors are not constrained to physical sensing devices: rather a sensor is anything that can estimate or calculate the value of a phenomenon, so a device or computational process or combination could play the role of a sensor. The representation of a sensor in the ontology links together what it measures (the domain), the physical sensor (the device) and its functions and processing (the models). Parts of the ontology are well aligned with SensorML and O&M, but parts are not, and the group is working to understand how differences from (and alignment with) the OGC standards affects the application of the ontology.
JRC Directorate:Sustainable Resources

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