## 6 Experimental Section and Analysis
### Comparison Experiments of Invulnerability Analysis
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & \(\delta=0\) & \(\delta=2\) & \(\delta=10\) \\ \hline \(\alpha=0.05\) & 0.92 & 0.904 & 0.816 \\ \(\alpha=0.1\) & 0.88 & 0.844 & 0.65 \\ \(\alpha=0.15\) & 0.82 & 0.776 & 0.43 \\ \(\alpha=0.2\) & 0.67 & 0.648 & 0.18 \\ \(\alpha=0.25\) & 0.61 & 0.51 & 0.1365 \\ \(\alpha=0.3\) & 0.53 & 0.438 & 0.1357 \\ \(\alpha=0.35\) & 0.5 & 0.354 & 0.1311 \\ \(\alpha=0.4\) & 0.44 & 0.282 & 0.1144 \\ \(\alpha=0.45\) & 0.37 & 0.234 & 0.1077 \\ \(\alpha=0.5\) & 0.28 & 0.21 & 0.1009 \\ \(\alpha=0.55\) & 0.22 & 0.186 & 0.0941 \\ \(\alpha=0.6\) & 0.18 & 0.168 & 0.0873 \\ \(\alpha=0.65\) & 0.15 & 0.148 & 0.0805 \\ \(\alpha=0.7\) & 0.12 & 0.116 & 0.0737 \\ \(\alpha=0.75\) & 0.1 & 0.091 & 0.0669 \\ \(\alpha=0.8\) & 0.08 & 0.076 & 0.06 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Statistical table of the traditional attack strategy data under different values of the attack accuracy. Figure 6: Invulnerability analysis of the traditional attack strategy under different values of the attack accuracy. subgraph may not be capable of performing related tasks. Therefore, our paper proposes an improved tree attack strategy to get add a further simulation comparison experiment. Both of the attacks are performed based on deliberate attacks in \(\delta=10\). With the breadth of the attacks increasing, the two attack strategies present different experimental results. As shown in Figure 7, the traditional attack strategy first has a faster deteriorating trend than the improved tree attack strategy. However, with the attack breadth increasing, the first cross point appears between the two curves. It shows that on the condition of a small attack breadth, the traditional attack strategy tends to attack the node with large characteristic parameters, and its attack situation is an \"ulcerative\" development. Meanwhile, in the improved tree attack strategy, the secondary attack would be performed on the branch node connected to the root node. Therefore, under the condition of a lower attack breadth, its invulnerability is higher than for the traditional attack strategy. As the breadth of the attacks increases, the second cross point appears between the two attack strategies. In the attack process between the first and second cross points, due to the organizational structure and the connecting relationship of SBIN studied in this paper, the invulnerability of the improved tree attack strategy is significantly reduced. This result proves that the degree of nodes connected to the root node or the root sibling node is low. When the root node or the root sibling node is attacked, the nodes with smaller degrees will be attacked, making the invulnerability of the whole network decline rapidly. This also proves the effectiveness of the improved tree attack strategy. Since the improved tree attack strategy implements a layering and an attack based on the node connection relationship, when the attack breadth \(\alpha>0.2\), the invulnerability metric based on the improved tree attack strategy is smoothed down, while the invulnerability metric of the traditional attack strategies drops significantly. This is because the attacking node in the improved tree attack strategy becomes the node with a large degree, while the traditional attack strategy keeps attacking the related nodes proportionally. Therefore, it brings more damages to the entire network than the improved tree attack strategy does. Finally, when the attack breadth reaches 0.75, the invulnerability of the whole network under the improved tree attack strategy reduces to 0. This indicates that there exist almost no interconnected nodes in the network, so it cannot complete any related SBIN tasks. This is more practical than the traditional attack strategy, which cannot achieve the task function even if there are interconnected edges. Figure 7 shows the invulnerability analysis of SBIN under different attack strategies, while the relevant data analysis is shown in Table 5.  
Figure 7: Invulnerability analysis under different attack strategies \(\delta=10\).