# UCLAONT: Ontology-Based UML Class Models Verification Tool updates
## 5 Experimental Results  
We implemented our approach as a Java prototype tool which has been already discussed in the previous section. For the subject of our study, we consider 11 different UML class models in which six models are used for association verification, 5 are used for XOR constraints. The Bellman-Ford algorithm [57] has been used to compare the proposed method because Bellman-ford is also a graph-based technique for detecting negative weight critical cycles. Many current verification techniques have employed the same with a little bit of adjustment for verification of satisfiability of association constraint. Furthermore, we also compared the proposed tool with UMLtoCSP and Alloy because they are widely used. To be justified, the proposed approach should provide an advantage over OCL based  
Figure 7: Verification Result Generated from UCLAONT.  
approach that does not support direct verification of XOR constraint. We thus compared the performance of the proposed approach with UMLtoCSP and UML2 Alloy, which support verification of the UML class model with OCL.  
For the performance verification of the proposed tool, the experimental setup was made to run on a Core i7 machine with 4 GB of RAM. However, UMLtoCSP tool does not execute on 64-bit architecture due to this experimental setup was made to run on Core2 Duo 1.34 GHz computer with two Gigabytes of RAM.  
The implemented approach in UCLAONT is very prompt and can check the correctness of large and complex model within a few milliseconds, as shown in Table 1 and Figure 8. For example, a class model containing 100 classes and 100 associations can be verified in 0.68 s in Alloy [44] and 0.89 s in UMLtoCSP [15; 43]. On the other side, UCLAONT takes only 0.003963 s. The presented tool offers two major advantages compared to other similar tools. First, it supports verification of large class model in a reasonable time, such as a class model containing 1000 classes and 1000 associations it takes only 0.090366 s. Secondly, it provides unbounded verification of XOR constraints and dependency relationships.  
Table 2 presents the execution time to verify the XOR models. For the first model, that is, Project-Tasks, the proposed tool takes on average 0.035 s with three classes and 1 XOR association. In Order Management, which has XOR constraints of type 2 (XOR on multiple associations), the proposed tool takes on average 0.103 s with eight classes and three XOR association constraints. In the Restaurant model, which has XOR constraints of type 1 (XOR on single association), the proposed tool takes on average 0.100 s with eight classes and three XOR associations. the Meta-model of value properties attributes model, which has both types of XOR constraints takes on average 0.080 s. Finally, for checking the proposed tool's performance on a large model, an experiment is performed on Programmed 4, which  
\begin{table}
\begin{tabular}{l c c c c} \hline \hline
**Model** & **Classes** & **Associations** & **UMLTOCSP** & **Alloy** & **UMLtoONTO** \\ \hline Employee Department & 3 & 5 & 0.032 s & 0.032 s & 0.00099 s \\ \hline Travel Agency & 12 & 12 & 0.51 s & 0.51 s & 0.00210 s \\ \hline Pet Store & 18 & 19 & 0.65 s & 0.631 s & 0.00328 s \\ \hline Programmed 1 & 100 & 100 & 0.89 s & 0.686 s & 0.003963 s \\ \hline Programmed 2 & 500 & 500 & Timeout & 3.890 s & 0.04534 s \\ \hline Programmed 3 & 1000 & 1000 & Timeout & 7.28 s & 0.090366 s \\ \hline \hline \end{tabular}
\end{table}
Table 1: Experimental Results.  
Figure 8: Verification Time of UML Class Models with UMLtoCSP, Alloy, and UCLAONT.  
has 100 classes, 200 associations, 100 XOR constraints, and the proposed tool takes on average 0.570 s.