## 3 Experiments
### Independent Operation of the Microwave Oven  
Upon acquiring operational electrical signals from the Midea microwave oven, the collected signals were segmented into electrical behavior events. As indicated by the arrows in Figure 9 below, segments between points A and B, C and D, and E and F represent sub-events in the microwave's operation.  
After event identification, an analysis of the current signals was conducted to determine central clusters for the 1 st, 3 rd, 5 th, and 7 th harmonics, as detailed in the figure in Appendix A, Figures A4-A6; each cluster position is summarized in Table 3.  
The Euclidean distances from the data center of each current signal to the predetermined centers are listed in Table 4.  
Utilizing the previously mentioned formula, the probability values for each power setting of the microwave oven were calculated as shown in Table 5.  
The resulting usage probability values exceeded the predefined threshold \(\varepsilon\), indicating successful identification of the microwave oven's operational status in all three experiments.  
\begin{table}
\begin{tabular}{c c c c} \hline  & **1 st Harmonic** & **3 rd Harmonic** & **5 th Harmonic** & **7 th Harmonic** \\ \hline \multirow{3}{*}{Low mode} & 0.029 & 0.000785 & 0.002973 & 0.001964 \\  & 0.598 & 0.570786 & 0.306913 & 0.0491 \\  & 1.788343 & 0.418779 & 0.422167 & 0.400084 \\ \hline \multirow{3}{*}{Medium mode} & 0.03312 & 0.00125 & 0.003243 & 0.002446 \\  & 0.919454 & 0.742069 & 0.27549 & 0.100012 \\  & 0.203 & 0.189 & 0.225 & 0.0752 \\ \hline \multirow{3}{*}{High mode} & 0.000759 & 0.001805 & 0.001805 & 0.001088 \\  & 0.619129 & 0.601373 & 0.2207 & 0.413577 \\ \cline{1-1}  & 0.175 & 0.18 & 0.2103 & 0.777497 \\ \hline \end{tabular}
\end{table}
Table 4: The Euclidean distances of each current signal to the predetermined center of Midea microwave oven.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline  & **1 st Harmonic** & \multicolumn{2}{c}{**3 rd Harmonic**} & \multicolumn{2}{c}{**5 th Harmonic**} & \multicolumn{2}{c}{**7 th Harmonic**} \\ \hline  & **I/A** & **U/V** & **I/A** & **U/V** & **I/A** & **U/V** & **I/A** & **U/V** \\ \hline \multirow{3}{*}{Low mode} & 0.1328 & 220.2 & 0.005 & 220.2 & 0.004118 & 220.2 & 0.005118 & 220.2 \\  & 2.92 & 220 & 1.449 & 219.9 & 0.6052 & 220 & 0.061 & 219.8 \\  & 3.183 & 219.9 & 1.613 & 220 & 0.5981 & 219.8 & 0.1381 & 219.9 \\ \hline \multirow{3}{*}{Medium mode} & 0.1089 & 220.2 & 0.004432 & 220.2 & 0.003669 & 220.2 & 0.002872 & 220.2 \\  & 2.918 & 220 & 1.612 & 220 & 0.6187 & 220 & 0.07556 & 220 \\  & 5.165 & 219.5 & 1.916 & 219.5 & 0.7022 & 219.5 & 0.2081 & 219.5 \\ \hline \multirow{3}{*}{High mode} & 0.006241 & 220.2 & 0.001805 & 220.2 & 0.001805 & 220.2 & 0.001736 & 220.2 \\  & 2.974 & 220 & 1.518 & 220 & 0.6227 & 220 & 0.7333 & 220 \\ \cline{1-1}  & 5.062 & 219.5 & 1.803 & 219.5 & 0.6747 & 219.5 & 0.2141 & 219.5 \\ \hline \end{tabular}
\end{table}
Table 3: Central cluster positions of harmonics of Midea microwave oven.  
\begin{table}
\begin{tabular}{c c c c} \hline  & **Low Mode** & **Medium Mode** & **High Mode** \\ \hline \multirow{2}{*}{Probability} & 89.1\% & 94.4\% & 92.0\% \\ \hline \end{tabular}
\end{table}
Table 5: Results of calculated probabilities.  
Figure 9: Three operation power modes of Midea microwave oven of independent operation.