## 3 Data Analysis
### Two-Factor ANOVA on Controller Situational Awareness Related Indicators
#### 3.2.2 Analysis of Heart Rate Variability Parameters in Air Traffic Controllers
We observed no significant interaction between tiredness state and controller qualifications (F = 0.318, \(p\) = 0.579). The condition of weariness significantly affected the HF parameter. Most people use the HF index, which indicates high-frequency sympathetic nervous system activity similar to LF, to assess brain function. As mental stress increases, this measure often declines. Figure 4d illustrates \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Norm** & **Condition** & **F** & \(p\) \\ \hline \multirow{4}{*}{SDNN} & Fatigue state & 0.624 & 0.43 \\  & Controller qualifications & 2.002 & 0.172 \\  & Both Interaction & 0.00 & 0.987 \\ \hline \multirow{4}{*}{NN50} & Fatigue state & 5.256 & 0.033 \\  & Controller qualifications & 0.661 & 0.426 \\  & Both Interaction & 0.100 & 0.755 \\ \hline \multirow{4}{*}{LF} & Fatigue state & 0.017 & 0.899 \\  & Controller qualifications & 0.014 & 0.908 \\  & Both Interaction & 0.106 & 0.749 \\ \hline \multirow{4}{*}{HF} & Fatigue state & 6.631 & 0.018 \\  & Controller qualifications & 0.613 & 0.443 \\  & Both Interaction & 0.318 & 0.579 \\ \hline \multirow{4}{*}{RMDSS} & Fatigue state & 0.862 & 0.364 \\  & Controller qualifications & 0.137 & 0.715 \\ \cline{1-1}  & Both Interaction & 2.630 & 0.121 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Two-factor ANOVA for HRV. that when the fatigue levels of remote tower controllers fluctuate, both seasoned and novice controllers exhibit an upward trend in HF, with novices displaying a little lesser rise compared to their experienced counterparts. The examination of heart rate variability metrics underscores the substantial influence of psychological stress on the physiological reactions of air traffic controllers. Comprehending the dynamics of HRV might facilitate the identification of possible stress-related problems that may result in human mistakes in air traffic control. Ongoing oversight and assistance in managing psychological stress may improve safety and performance in this high-pressure setting. Further research is required to explore therapies aimed at enhancing heart rate variability and mitigating the effects of psychological stress in controllers. We performed a two-way ANOVA on the RMDDS results and found that neither the level of tiredness (F = 0.862, \(p\) = 0.364) nor the qualifications of the controllers (F = 0.137, \(p\) = 0.715) had a big effect on the RMDDS parameter. Furthermore, we observed no significant interaction between the tiredness state and controller qualifications (F = 2.630, \(p\) = 0.121). The interaction between controller fatigue and qualifications significantly influenced the RMDDS parameter. As a sensitive way to measure parasympathetic nerve activity, the RMDDS index finds the root mean square of the differences between two or more normal R-R intervals. As mental stress increases, this measure often declines. Figure 3(e) illustrates that while the tiredness condition of remote tower controllers fluctuated,  
Figure 4: Comparison of two-factor ANOVA results for heart rate variability parameters. the RMDDS index for experienced controllers decreased, but the RMDDS index for trainee controllers had an upward trend.