# An Ontology for Spatio-Temporal Media Management and an Interactive Application
## 6 Evaluation of SDM Ontology
### Evaluation by OOPS!  
The SDM Ontology was also evaluated using OntOlogy Pitfall Scanner! (OOPS!) [55]. OOPS! is a RESTful web service that detects common hazards that can lead to ontology flaws according to the existing literature. The SDM Ontology detected several important or minor hazards but no critical hazards. The following are the important hazards detected.  
**Important pitfalls**  
1. The prime relationships among elements are not defined The SDM Ontology contains elemental relationships that are prime. However, the definition does not reflect them because they are not discussed in detail.
2. The subject or object of the property is not defined These warnings occur for properties referenced using external ontologies and do not consist of a nature that should be defined within the SDM Ontology. We believe that the handling of subjects and objects that are not included in the definition of the SDM Ontology should be handled by the operational rules at the time of data production.
3. Use of recursive definitions Recursiveness is an intentionally designed structure. We believe that operational rules should handle problems such as the circular references that may occur with recursive descriptions during data production.  
**Minor pitfalls**  
1. Existence of independent ontology elements This warning occurs for class definitions with an external ontology as a superclass. This structure was intentionally designed.  
\begin{table}
\begin{tabular}{l r} \hline \hline  & **Index** & **Value** \\ \hline Number of classes & 30 \\ Number of properties & 31 \\ - Object properties & 23 \\ - Data properties & 8 \\ Number of individuals & 0 \\ Number of external ontologies using it & 0 \\ Number of external ontologies used & 3 \\ - Percentage of external classes & 10.0\% \\ - Percentage of external properties & 16.1\% \\ \hline \hline \end{tabular}
\end{table}
Table 1: Indicators on knowledge coverage and popularity.  
2. No inverse relationship defined This warning also occurs for properties referenced from external ontologies and is an intentionally designed structure. The properties inside the SDM Ontology have inverse relationships defined.
3. No label/annotation present This warning also occurs for properties referenced from external ontologies and is an intentionally designed structure.
4. Misuse of labels and annotations This warning occurs when there is a misuse of a label/annotation property for human reading. We believe that a warning is being generated for a label definition defined for symmetry with the definitions of other elements. However, it has not yet been determined whether it should be corrected.  
As described in Section 3.3.1, the **Context** class is used as a standard interface for semantic information described in external ontologies. It is up to the user to determine what external ontology to use, and the SDM Ontology definition does not include them. Moreover, recursion is noted as an important pitfall, but this is an intentionally designed structure. Both cases suggest limitations in evaluation methods that refer only to the ontology definition. In order to use the SDM Ontology to create a valid dataset according to the design intent, it is necessary to embed a judgment function in the application that creates the RDF data.