## 3 Results  
1. Sounds designed with local guidelines seem to be interpreted in a more suitable manner.  
We evaluated sound perception using semantic scales. We provided six pairs of descriptors, which were then rated from one to seven, as shown in Table 11.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Number** & **Semantic Scales** & **Scale** \\ \hline
1 & Frightening–Reassuring & \\
2 & Fast-Slow & \\
3 & Warm–Cold & \\
4 & Deep–High & \\
5 & Serious–Not Serious & \\
6 & Not Alerting–Alerting & \\ \hline \hline \end{tabular}
\end{table}
Table 11: Semantic scales.  
Figure 6: Pictograms added to a simulated head-up display.  
Figure 7: Procedures.  
We then evaluated the differences in rating between the corresponding sounds using the chi2 test. Out of the three pairs of sounds (A1/A2, B1/B2, and C1/C2), two showed significant differences. The A2 sound was evaluated with a significantly higher seriousness degree than the A1 sound, reaching a 4.4 mean, where A1 reached 3.5. Because the A sounds were supposed to provide a medium perceived value for the seriousness degree, the sound A1 following local guidelines seems more appropriate. While the B1/B2 pair showed no significant differences, both components failed to reach the expected levels for AL and SE. The C1/C2 pair did show significant differences. Four pairs of descriptors are significant: seriousness and alertness perceptions, deepness, and fear levels. The C sounds were designed as notification sounds, and C2 was evaluated with a very high level of alertness and fear. These levels not being suitable for notification purposes, the C1 sound, designed with local guidelines, seems more appropriate. Detailed tables for the simulator usability survey's chi2 test are shown in Tables 12 and 13.  
2. Local guidelines' sounds show a tendency towards quicker reactions.  
When comparing reaction time results from the two simulations, a significant tendency towards quicker reactions appears with the local guidelines' sounds, as shown in Tables 14 and 15.  
Workload shows a trend towards lower values with local guidelines, while overall self-rated performance seems higher with French guidelines.  
After completion of the NASA-TLX test, several scores were calculated for evaluation. A significant tendency towards lower mental and temporal demands appears with the local-designed sounds. On the other hand, a significant tendency towards better self-evaluated performance scores appears with the French guidelines, as shown in Table 16.  
A linear model can be created to predict reaction time from our dataset.  
A linear model is significant and relies mostly on the self-evaluated satisfaction variable and NASA-TLX evaluation of mental demand. After applying ANOVAs to the different categories (sound evaluation, the NASA-TLX, personal evaluation, etc.), we identified the most important parameters in regard to predicting reaction time. We then grouped these variables and searched for the most efficient linear model using the AIC. The outcome is a model using seven variables: satisfaction, easiness of understanding sounds' seriousness degree, mental demand, temporal demand, physical demand, performance, and effort. The model has an R\({}^{2}\) of 0.72 and an adjusted R\({}^{2}\) of 0.62 and can therefore be considered significant.  
This suggests that a rise in the evaluation of satisfaction, or mental and temporal demand, results in an increase in reaction time. It is difficult to really draw conclusions on such observations considering the small sample used. We could still suggest that satisfaction may be linked to a \"secure\" feeling regarding the system. Feeling more secure and being more confident leads to longer reaction times. Similarly, an increase in workload would decrease the capacity to react quickly. The fourth most significant parameter is effort. Here, when the effort increases, reaction time decreases. This trend seems to go against the previous observations. This concludes the observations made on our pre-test.