# Ontological Representation of Smart City Data: From Devices to Cities
## 4 Ontology Design Patterns Proposal for Smart City Ontologies
### Key Performance Indicator ODP  
This pattern has been inspired by the _gci_ and _smart-city_ ontologies. In addition, the models analyzed in order to define the requirements for this domain are the FIWARE data model for KPI ([[http://fiware-datamodels.readthedocs.io/en/latest/KeyPerformanceIndicator/doc/spec/index.html](http://fiware-datamodels.readthedocs.io/en/latest/KeyPerformanceIndicator/doc/spec/index.html)]([http://fiware-datamodels.readthedocs.io/en/latest/KeyPerformanceIndicator/doc/spec/index.html](http://fiware-datamodels.readthedocs.io/en/latest/KeyPerformanceIndicator/doc/spec/index.html))) and ISO:37120:2014 ([[https://www.iso.org/standard/62436.html](https://www.iso.org/standard/62436.html)]([https://www.iso.org/standard/62436.html](https://www.iso.org/standard/62436.html))). Table 11 presents the ODP for Key Performance Indicators. The _UnitOfMeasure_ concept has been defined in order to represent the units in which the KPI is measured and may be modeled as was explained in the Measurement pattern. In addition, the concept _TemporalEntity_, as in the case of the Event ODP, has been included in order to represent the period of time over which the KPI is measured and the timestamp when the KPI value is calculated. Specifically, the OWL-Time concepts _Interval_ and _Instant_ could be used to represent both requirements.  
\begin{table}
\begin{tabular}{|c|c|} \hline
**Name:** & Key Performance Indicator \\ \hline \multicolumn{2}{|c|}{**Description**} \\ \hline This pattern provides a model for a method to measure the performance in a city in order to evaluate the success of an organization or of a particular activity in which it engages. \\ \hline \multicolumn{2}{|c|}{**Requirements**} \\ \hline
**KPI-1:** & A Key Performance Indicator (KPI) is a type of performance measurement. KPIs evaluate the success of an organization or of a particular activity in which it engages. \\
**KPI-2:** & A KPI has a name. \\
**KPI-3:** & A KPI can assess an organization, service, process, or product. \\
**KPI-4:** & A KPI has a description. \\
**KPI-5:** & A KPI can be calculated by an organization. \\ KPI-6:** & A KPI can aggregate different measurements. \\
**KPI-7:** & A KPI can have a calculation period over which it is measured. \\
**KPI-8:** & A KPI can take a given value in a given timestamp. \\
**KPI-9:** & A KPI can have a creation date. \\
**KPI-10:** & A KPI can have an expiration date. \\
**KPI-11:** & A KPI can have a last update date. \\
**KPI-12:** & A KPI might refer to a given location of an area. \\
**KPI-13:** & A KPI might refer to a given address of an area. \\
**KPI-14:** & A KPI might refer to an area denoted by textual geographical information such as district, borough, or other specification of the KPI coverage. \\
**KPI-15:** & A KPI can have an indicator unit. \\
**KPI-16:** & A KPI can be a measure of demography, characteristics, activity, or performance. \\ \hline \end{tabular}
\end{table}
Table 11: Key Performance Indicator ODP.  
The _Agent_ concept, the same as explained in the Event ODP, has been included in order to represent for whom the performance is measured. In addition, this concept has been extended by means of the _Organization_ in order to represent a public administration or a private entity that could calculate the KPI. Finally, the concept _EntityList_ represents a list of entities whose data are aggregated. It could be represented by means of the _StructureValue_ concept from the schema model, as is explained in the FIWARE data model specification.