## 6 Experimental Section and Analysis  
### Comparison Experiments of Invulnerability Analysis  
Based on the definition of the attack information metric index and strategy algorithm, we carry out the simulation analysis of SBIN. First, the maximum connected subgraph is selected as the metric index to measure the effect before and after the network attack. Second, under the traditional attack strategy and the improved tree attack strategy, we set different attack information breadth and accuracy parameters, and delete the selected node and the connected edge according to the unequal probability sampling rule. We analyze the invulnerability effect of different strategies on SBIN. Finally, the paper compares the advantages and disadvantages of the two attack modes under the condition that the parameters are the same but the strategies are different. In this paper, 20 experiments were carried out independently, and the mean value of the invulnerability measurement index was calculated last, verifying the universality of the simulation results. 1. Invulnerability analysis under different values of the attack accuracy of the traditional attack strategy  
In the process of analyzing the invulnerability under different values of the attack accuracy based on the traditional attack strategies, the attack breadth was first quantitatively controlled. With the increase of the attack breadth, more and more nodes had been attacked in SBIN. The number of its deleted nodes also increases gradually, which directly leads to a decrease of invulnerability and makes the whole simulation curve show a downward trend. Under the condition of a certain attack breadth, the attack accuracy of \(\delta=0\), \(\delta=2\) and \(\delta=10\) are studied respectively. When \(\delta=0\), the selected attack nodes are random. Therefore, the whole  
Figure 5: Analysis diagram of adding a shortcut. network is in a state of random failure under the traditional attack strategy, and the performance of the related nodes and connection edges tends to be flat with the increase of the attack breadth. When \(\delta=10\), the whole network presents a sharp downward trend at the very beginning. Because the attack accuracy increases, the selected network node was the node with the larger characteristic parameters in the whole network. When these nodes were attacked and deleted, the connected edges were deleted. This makes the whole network invulnerability reduce rapidly. In the research process of this paper, we found that when the attack accuracy increases to \(\delta=20\), the change scope is close to \(\delta=10\). Consequently, it can be considered that the node attack accuracy of \(\delta=10\) belongs to a deliberate attack, which directly leads to the decline of the invulnerability of the whole network. Figure 6 shows that the schematic diagram of the invulnerability of SBIN changes with the increase of the attack breadth in the traditional attack strategy, at the different values of the attack accuracy; the relevant data analysis is shown in Table 4.  
2. Invulnerability analysis of different attack strategies in \(\delta=10\)  
As the 'ulcerative' results appearing under the traditional attack strategy indicate, although the invulnerability declines to some extent, the attacked network composed of the largest connected