# Airport Field Path Optimization Method Based on Conflict Hotspot Avoidance Mechanism
## 4 Example Analysis
\begin{table}
\begin{tabular}{c c} \hline \hline
**Flight Number** & **Taxing Path** & **Moment of Aircraft Crossing Point** \\ \hline CES2558 & [10, 9, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 40, 107, 106, 61, 76, 75, 74, 73, 72, 64, 135, 118, 136, 169] & [2474-2483-2497-2513-2527-2543-2553-25563-2577-2602-2609-2616-2623-2648-2671-2696-2703-2710-2717-2731-2739-2749-2753-2758-2763-2767] \\ CES5348 & [171, 133, 120, 130, 130, 66, 65, 64, 63, 62, 109, 284, 41, 42, 43, 44, 45, 46, 47, 48, 49, 11, 10] & [2698-2703-2711-2721-2726-2737-2764-2788-2795-2820-2843-2868-2875-2900-2927-2937-2953-2967-2983-2991-2998-3013] \\ CSN6310 & [167, 137, 117, 118, 135, 64, 63, 62, 109, 108, 41, 42, 43, 44, 45, 46, 47, 48, 49, 11, 10] & [2765-2768-2771-2780-2777-2791-2816-2823-2848-2871-2896-2903-2928-2955-2965-2981-2995-3011-3019-3026-3041] \\ CSN3210 & [10, 9, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 38, 150, 158] & [3516-3525-3539-3555-3569-3585-3595-3605-3619-3644-3651-3658-3666-3676-3683-3691-3695] \\ CCA4314 & [10, 9, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 37, 151, 157] & [3516-3545-3559-3575-3589-3605-3615-3625-3639-3664-3671-3678-3686-3696-3709-3721-3728-3736-3740] \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Partial aircraft taxi paths and crossing moments. Figure 8: Plot of change in fitness value during algorithm evolution. Aiming at the above-mentioned aircrafts that may have conflicts in the hotspot area, the hotspot area avoidance mechanism is used to judge the priority between the aircraft and calculate the waiting time cost of the two solution strategies of decelerating and waiting, and choosing the suboptimal taxiing path, to select the solution strategy for the aircraft and optimize the taxiing path. Some of the optimized paths and crossing point moments for aircraft are shown in Table 3.  
According to the data in the table, it can be found that:  
(1) Aircraft CES2558, CES5348, and CSN6310 occupy the critical hotspot area HS64 successively, the taxiing time of inbound aircraft CES2558 is 293 s, the taxiing time of departing aircraft CES348 is 315 s, and the taxiing time of departing aircraft CSN6310 is 276 s. Therefore, the aircraft CES5348 has the longest taxiing time, so the aircraft is given the priority to pass the hotspot area; the inbound aircraft CES2558 occupies the hotspot area first, and the cost of its deceleration and waiting strategy is much larger than that of the alternative path, so the aircraft CES2558 needs to choose the suboptimal alternative path to avoid the hotspot area HS64. (2) Aircraft CES5348 and aircraft CSN6310 will occupy the critical conflict hotspot area HS64 one after another, since both aircraft are departing aircraft and will occupy the same sequence of same-direction path nodes in the future; therefore, the time cost of selecting the suboptimal alternative path will be much larger than the deceleration waiting time, so aircraft CSN6310 chooses the conflict resolution strategy of deceleration waiting, with a waiting time of 13 s. The waiting time is 13. (3) Aircraft CSN3210 and aircraft CCA4314 are both inbound aircraft with taxi times of 179 s and 204 s, respectively, so aircraft CCA4314 is prioritized to pass through hotspot area HS23. Since aircraft CSN3210 occupies the hotspot area first, its deceleration waiting time cost is the 60 s, and the time cost of rerouting the second-best alternative path is 43 s; therefore, the solution strategy of rerouting the suboptimal alternative path is chosen to ensure that all conflicts are avoided with the shortest possible total taxiing time of the aircraft.