## 3 Experiment and Results Analysis
### Simulation Experiment  
The Sentinel2 acquisition task was used to realize the simulation algorithm experiment of dynamic task scheduling. The task set was taken from one of the four resource nodes, and detailed information about task length and task execution nodes is shown in Table 1. The download power is the average download speed of the node performing this type of task over a period of time. The energy consumption per unit time represents the total power of the node when performing tasks, and the unit task cost represents the node's cost for this type of task. In order to compare the task performance under different algorithms, FCFS-PSO, SJF-PSO, MAX-MAX-PSO, and PSO were each implemented. The maximum iteration number of each algorithm is 500, the number of particles is 20, the number of tasks is 50, \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Node Number**} & \multirow{2}{*}{**Download Power (kB/s)**} & **Energy Consumption** & **Unit Task Cost** \\  & & **per Unit Time (wh)** & **(CNY)** \\ \hline
1 & 2914.7 & 300 & 2 \\
2 & 5049.45 & 330 & 4 \\
3 & 4028.56 & 320 & 3 \\
4 & 1531.6 & 285 & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: List of node resources. 100, and 150, and the number of task nodes is 4. The node network transmission capacity prediction module adopts the BP neural network algorithm, and the update frequency of the prediction algorithm and the task scheduling algorithm is set as 3 min. Table 2 lists the total working hours of each node and the number of tasks assigned to each node for different algorithm scheduling results. In Table 3, the scheduling results of different algorithms are compared on the basis of the five indexes of the average task execution time, best fitness value, total task execution time, total task energy consumption, and total task cost under different scheduling algorithms. As shown in Figure 2, Node 4, with the weakest download force, had the least number of tasks assigned but the longest working time. Node 2 and Node 3, with similar differences in download power, basically maintained the same working time during the execution of tasks. Nodes with similar download power had little difference in the number of tasks assigned. Therefore, the download power of nodes is positively correlated with the working time for executing tasks and the number of tasks assigned. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{
\begin{tabular}{c} **The** \\ **Number** \\ **of Tasks** \\ \end{tabular} } & \multirow{2}{*}{**Algorithm**} & \multicolumn{2}{c}{**Node 1**} & \multicolumn{2}{c}{**Node 2**} & \multicolumn{2}{c}{**Node 3**} & \multicolumn{2}{c}{**Node 4**} \\ \cline{3-10}  & & \multicolumn{1}{c}{**Time**} & \multicolumn{1}{c}{**The**} & \multicolumn{1}{c}{**Time**} & \multicolumn{1}{c}{**Time**} & \multicolumn{1}{c}{**Time**} & \multicolumn{1}{c}{**Time**} & \multicolumn{1}{c}{**Time**} & \multicolumn{1}{c}{**Time**} & \multicolumn{1}{c}{**Time**} & \multicolumn{1}{c}{**Time**} \\  & **Time** & **Number** & **of Tasks** & **(min)** & **Number** & **of Tasks** & **(min)** & **Number** & **of Tasks** & **(min)** & **Number** \\ \hline \multirow{9}{*}{100} & FCFSPSO & 3544 & 14 & 2254 & 18 & 1861 & 14 & 5246 & 4 \\  & SJFPSO & 3027 & 14 & 1874 & 17 & 2426 & 14 & 5998 & 5 \\  & MAX\_MAX\_PSO & 3152 & 14 & 1935 & 16 & 2349 & 14 & 5761 & 6 \\  & PSO & 3543 & 13 & 2253 & 13 & 1861 & 12 & 5246 & 12 \\  & FCFSPSO & 5675 & 33 & 3858 & 31 & 3663 & 23 & 9776 & 13 \\  & SJF\_PSO & 5691 & 28 & 3166 & 34 & 4041 & 26 & 11,032 & 12 \\  & MAX\_MAX\_PSO & 5586 & 30 & 3346 & 33 & 4117 & 22 & 10,439 & 15 \\  & PSO & 5676 & 24 & 3858 & 32 & 3663 & 29 & 9776 & 15 \\  & FCFSPSO & 8951 & 45 & 6065 & 54 & 5805 & 33 & 14,807 & 18 \\  & SJF\_PSO & 8651 & 44 & 5128 & 47 & 6485 & 36 & 16,678 & 23 \\  & MAX\_MAX\_PSO & 8764 & 37 & 5174 & 50 & 6427 & 42 & 16,464 & 21 \\  & PSO & 8951 & 43 & 6065 & 50 & 5805 & 33 & 14,807 & 24 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Task execution results of different algorithms.