## Guide for Extensions

### 1 Getting aligned with FIESTA-IoT’s semantic data model

#### 1.1 FIESTA-IoT ontology alignment phase

The FIESTA-IoT ontology is an outcome of a thorough analysis of all the different platforms that are part of the FIESTA-IoT’s initial testbed federation. These platforms are SmartSantander (Spain), Smart ICS (UK), Soundcity (France) and KETI (South Korea). Amongst the assets, where sensors stand out as the dominant realm, we have outlined the most appropriate means of how to describe a single resource, focusing on the essential aspect that must be defined for a complete minimal definition of a resource. These include: physical location, owner (testbed), sensor or sensors that are embedded in that concrete resource, their respective quantity kind and unit of measurement. Besides these key concepts, in the graph another set of concepts hold a secondary (optional) information, like VirtualEntity, Coverage or Source, just to name a few.

They are addressed to describe additional information about the resources, although they are not strictly necessary. Moreover, there is a Metadata class (right side of the figure), where any kind of information could be appended, thus opening the ontology to non-foreseen items (for instance, if a sensor follows a synchronous operation, we might want to represent its frequency or rate, said in other words, the time between consecutive observations).

Note that the current version of the ontology is clearly biased towards the sensor realm, as we only provide the concepts for ssn:SensingDevice. Although, we have introduced the concepts of iot-lite:ActuatingDevice and iot-lite:TagDevice, but we have not thoroughly dived into the details.

Together with the part in charge of the description of the resources, we have modelled how an observation harvested by one of these sensors would look like. Essentially, it answer the following questions: who (sensor that has actually measured the observation), where (physical location of the sensor), when (timestamp of the observation), what (quantity kind and unit of measurement of the observation) and last, and the most important, the value of the observation itself.