## 3 SEIRS-F Agent-Based Model
### Agents and Environmental Characteristics
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Type of Factors** & **Characteristics** & **Values** \\ \hline \hline \multirow{8}{*}{Sensors} & \multirow{2}{*}{Reliability state of sensor} & Normal state \\ \cline{3-3}  & & Failure state \\ \cline{3-3}  & & Low \\ \cline{3-3}  & & Reliability level & Medium \\ \cline{3-3}  & & High \\ \cline{3-3}  & & Low \\ \cline{3-3}  & Security level & Medium \\ \cline{3-3}  & & High \\ \cline{3-3}  & & True \\ \cline{3-3}  & Transmission capability & False \\ \cline{3-3}  & & Low \\ \cline{3-3}  & Battery power & Medium \\ \cline{3-3}  & & High \\ \hline \hline \multirow{8}{*}{Malware} & \multirow{2}{*}{Infection intensity} & Low \\ \cline{3-3}  & & Medium \\ \cline{3-3}  & & High \\ \cline{3-3}  & & \multicolumn{1}{c}{} \\ \cline{3-3}  & & \multicolumn{1}{c}{} \\ \cline{3-3}  & Target & Software function \\ \cline{3-3}  & & \multicolumn{1}{c}{} \\ \cline{3-3}  & & \multicolumn{1}{c}{} \\ \cline{3-3}  & & Battery power \\ \hline \hline \multirow{8}{*}{Network topology} & \multirow{2}{*}{Type of topologies} & Star topology \\ \cline{3-3}  & & Lattice-2d topology \\ \cline{3-3}  & & Random topology \\ \cline{3-3}  & & Low \\ \cline{3-3}  & & Risk of physical attack & Medium \\ \cline{3-3}  & & High \\ \cline{3-3}  & & Low \\ \cline{3-3}  & & \multicolumn{1}{c}{} \\ \cline{3-3}  & & \multicolumn{1}{c}{} \\ \cline{3-3}  & & \multicolumn{1}{c}{} \\ \cline{3-3}  & & \multicolumn{1}{c}{} \\ \cline{3-3}  & & \multicolumn{1}{c}{} \\ \cline{3-3}  & & \multicolumn{1}{c}{} \\ \hline \hline \multirow{8}{*}{Environment} & \multirow{2}{*}{Resource} & Medium \\ \cline{3-3}  & & High \\ \cline{3-3}  & & Repair \\ \cline{3-3} Maintenance & Maintenance behavior & Recharge \\ \cline{3-3}  & & Replacement \\ \cline{3-3}  & & Low \\ \cline{3-3}  & Maintenance cycle & Medium \\ \cline{3-3}  & & High \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Factors with their characteristics. Network topology: refers to the structure of the network. We will consider one characteristic of this agent:  
* Type of topologies: star topology, lattice-2d topology, and random topology. Environment: differs regarding the type and application of the WSN. In this work, we divided the environment by the risk of physical attack and the risk of malware attack, as follows:
* Risk of physical attack: sensors are deployed in hostile environments in a military surveillance application, which means high risk. Some attackers may attack the physical devices and information functions of the industrial infrastructure at the same time to achieve a higher success rate, which leads to medium risk. Sensors in other application scenarios are usually deployed in a friendly environment with close attention, and the risk of intentional physical attack is shallow, which is generally just accidental damage. * Risk of malware attack: Military environment corresponds to high risk, medium risk when the environment is industrial, and low risk when the environment is daily activities and Smart Home. Maintenance: this is related to the maintenance resources, behaviors, and cycle. The connectivity robustness of WSN is maintained by restoring the function of nodes after they suffer from physical or information shock. The two characteristics considered here are:
* Resource: The available maintenance resources, including materials and workforce, are not unlimited. The amount of resources is divided into a high level, medium level, and low level. * Maintenance behavior: in some environments, it is inconvenient or even impossible to recharge or repair the sensor nodes for WSN in hostile environments such as military surveillance applications. The failed nodes can only be replaced by re-dropping nodes regularly. In other scenarios, the node can be repaired or charged, but it also costs human resources. * Maintenance cycle: each can reset the remaining maintenance resources. There is an upper limit for one-time input of resources, and resources can be recovered over time.