# An Ontology-Based Expert System for Rice Disease Identification and Control Recommendation
## 5 RiceMan: Ontology and System Evaluation
### Ontology Evaluation
#### 5.1.2 Ontology Usage  
This evaluation was conducted to verify that our ontologies are valuable and can effectively facilitate our users with respect to the three important criteria: completeness, accuracy, and usefulness. Two groups of senior agronomists: two plant pathologists and two entomologists, from DRRD (The Division of Rice Research and Development under the Rice Department, Ministry of Agriculture and Cooperatives, Thailand), with 8-year experience on average, were involved. 1. **Evaluating the completeness of diseases and paddy insects:** we evaluated the completeness in terms of the number of diseases and insects provided in RiceDO (cf. Table 6). Two levels of completeness checking were executed. Firstly, we compared the modeled knowledge with the Rice Knowledge Bank maintained by the Rice Department of Thailand (Thai-KKB) [41]. Secondly, we verified the completeness based on domain experts' knowledge to ensure that it was applicable in practice. RiceDO covers most of the rice diseases in Thailand; however, it covers relatively fewer insects. \begin{table}
\begin{tabular}{l c c} \hline \hline \multicolumn{1}{c}{**Questions**} & \multicolumn{1}{c}{\begin{tabular}{c} **Average** \\ **(\%)** \\ \end{tabular} } \\ \hline \hline \multicolumn{1}{c}{**RiceDO**} & \multicolumn{1}{c}{\begin{tabular}{c} **RiceDO** \\ \end{tabular} } \\ \(1\) & The _class hierarchy_ in RiceDO is well defined and accurate. & 96 \\ \(2\) & The _object property hierarchy_ in RiceDO is well defined and accurate. & 92 \\ \(3\) & The _abnormalityGroup_ is appropriate to explain a group of abnormal characteristics. & 92 \\ \(4\) & The _axiom_ that represents each _disease’s characteristics_ is well defined and accurate by using the abnormalityGroup. & 100 \\ \(5\) & The _SymptembCharacteristic_ and _GrowthStageCharacteristic_, which are used to shorten axioms, are well defined and correct. & 96 \\ \hline \multicolumn{1}{c}{**Overall appropriate score of RiceDO**} & \multicolumn{1}{c}{\begin{tabular}{c} **95.2\%** \\ \end{tabular} } \\ \hline \hline \multicolumn{1}{c}{**TreadO**} & \multicolumn{1}{c}{\
\begin{tabular}{c} **TreadO** \\ \end{tabular} } \\ \(6\) & The _class hierarchy_ in TreatO is well defined and accurate. & 92 \\ \(7\) & The _object property hierarchy_ in TreatO is well defined and accurate. & 88 \\ \(8\) & The _axiom_ representing diseases that can be treated by each _biological control_ and _chemical control_ is well defined and accurate. & 88 \\ \hline \multicolumn{1}{c}{**Overall appropriate score of TreatO**} & \multicolumn{1}{c}{
\begin{tabular}{c} **(89.4\%)** \\ \end{tabular} } \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Verifying the appropriateness of RiceDO and TreatO ontologies \begin{table}
\begin{tabular}{l l c c} \hline \hline \multicolumn{1}{c}{\#} & \multicolumn{1}{c}{**Tasks**} & \multicolumn{1}{c}{\
\begin{tabular}{c} **Query Is** \\ **Written** \\ **Correctly** \\ \end{tabular} } & \multicolumn{1}{c}{
\begin{tabular}{c} **Average of** \\ **Query** \\ **Efficiency** \\ (\%) \\ \end{tabular} } \\ \hline \hline \(1\) & Infer rice disease from the following observations (single abnormality). & CQ 1 & Yes & 100 \\ \(2\) & Infer rice disease from the following observations (multiple abnormalities). & CQ 2 & Yes & 100 \\ \(3\) & Infer biological controls for each following disease. & CQ 4 & Yes & 100 \\ \(4\) & Infer chemical controls for each following disease. & CQ 5 & Yes & 92 \\ \(5\) & Use of a shortened axiom (compared to Task 1). & - & Yes & 100 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Query validation Though the number of insects' coverage seems insufficient, two of them frequently occur in rice fields, and three of them are carriers for some rice diseases (such as gall dwarf disease and rice tungro disease). 2. **Evaluating the accuracy of modeled knowledge:** two aspects were considered: (1) the correctness of the modeled axioms; and (2) the appropriateness of our vocabulary. Precisely, the participants were asked to consider if the modeled axioms were correct or not.