## 4 Experiments and Results
### EEG-Conformer with Different Bandpass Filter Parameters  
In the second sub-project with EEG-Conformer, the baseline model is trained with different orders of the filter and the minimum attenuations required in the stop band of Chebyshev type 2, as described in Table 14.  
After training 45 experiments, a fixed result and a variable result are selected. With regard to the fixed result, the best Chebyshev type 2 parameters \(N=4,rs=20\) for all 9 subjects are selected based on the average accuracy. Regarding the variable result, the best Chebyshev type 2 parameters \(N,rs\) for each subject are selected. Table 15 summarises the variable result.  
Figure 11: The column chart shows the accuracy between the EEG-Conformer baseline model, fixed model, and variable.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Subject** & **Baseline** & **Fixed Model** & **Variable Model** \\ \hline
**S1** & 83.99 & 87.54 & **88.26** \\
**S2** & 57.95 & 60.42 & **61.48** \\
**S3** & 94.51 & 91.94 & **95.24** \\
**S4** & 78.07 & 75.88 & 78.51 \\
**S5** & 78.62 & 77.90 & **79.35** \\
**S6** & 63.72 & 64.19 & **65.58** \\
**S7** & 88.81 & 88.09 & **92.42** \\
**S8** & 88.56 & 88.56 & **89.30** \\
**S9** & 82.58 & 82.95 & **84.09** \\
**Average** & 79.64 & 79.72 & **81.58** \\ \hline \hline \end{tabular}
\end{table}
Table 13: Accuracies of the EEG-Conformer baseline model, fixed model, and variable models.  
\begin{table}
\begin{tabular}{c c} \hline \hline \(N\) & 4, 5, 6, 7, 8 \\ \hline \(rs\) & 20, 30, 40, 50, 60, 70, 80, 90, 100 \\ \hline \hline \end{tabular}
\end{table}
Table 14: Experiment EEG-Conformer with different parameters of Chebyshev type 2 filter.  
Table 16 compares and visualises the accuracies of baseline EEG-Conformer, EEG-Conformer with a fixed bandpass filter, and EEG-Conformer with a varied bandpass filter. Chebyshev type 2 contributes to improving the accuracy of subject 1, subject 2, subject 4, and subject 7. Other subjects are approximate to the baseline model. The variable result obtained an average accuracy of 84.61%. The detailed accuracy of 9 subjects is in Table A4.  
Figure 12 shows a comparison of accuracies between baseline EEG-Conformer, EEG-Conformer with the best bandpass filter parameters (fixed bandpass filter), and EEG-Conformer with the best bandpass filter parameters of each subject from different trainings. This experiment aims to research the impact of different bandpass filter parameters on EEG-Conformer. The improvement in accuracy shows that the bandpass filter contributes to the robustness of EEG-Conformer.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Subject** & **Baseline** & **Fixed Bandpass Filter** & **Variable Bandpass Filter** \\ \hline
**S1** & 83.99 & 90.04 & **91.81** \\
**S2** & 57.95 & **63.96** & **63.96** \\
**S3** & **94.51** & 92.67 & 94.14 \\
**S4** & 78.07 & 81.58 & **86.40** \\
**S5** & 78.62 & **79.71** & **79.71** \\
**S6** & 63.72 & 66.98 & **71.16** \\
**S7** & 88.81 & 94.95 & **96.39** \\
**S8** & 88.56 & 88.56 & **89.30** \\
**S9** & 82.58 & 88.26 & **88.64** \\
**Average** & 79.64 & 82.97 & **84.61** \\ \hline \hline \end{tabular}
\end{table}
Table 16: Accuracy of baseline EEG-Conformer, EEG-Conformer with a fixed bandpass filter, and EEG-Conformer with a variable bandpass filter (%).  
Figure 12: The column chart shows the accuracies of baseline EEG-Conformer, EEG-Conformer with a fixed bandpass filter, and EEG-Conformer with a variable bandpass filter.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & **S1** & **S2** & **S3** & **S4** & **S5** & **S6** & **S7** & **S8** & **S9** \\ \hline \(N\) & 5 & 4 & 5 & 5 & 4 & 5 & 6 & 6 & 5 \\ \(rs\) & 30 & 20 & 40 & 20 & 20 & 20 & 20 & 90 & 90 \\ \hline \hline \end{tabular}
\end{table}
Table 15: Variable bandpass filter of EEG-Conformer.