## 4 Numerical Analysis
### Sensitivity Analysis
#### 4.2.2 Sensitivity Analysis of Maritime Transportation Cost to Port Equilibrium Profit  
Figure 7 shows the change in the maritime transportation cost difference on port equilibrium profit. It can be seen that when \(C_{B}^{sea}-C_{A}^{sea}=-3052.72\) RMB/TEU, Dalian Port has the lowest profit. When \(C_{B}^{sea}-C_{A}^{sea}>-3052.72\) RMB/TEU, the profit of Dalian Port increases with the increase in \(C_{B}^{sea}-C_{A}^{sea}\), while when \(C_{B}^{sea}-C_{A}^{sea}<-3052.72\) RMB/TEU, Dalian Port's profit decreases with the increase in \(C_{B}^{sea}-C_{A}^{sea}\). Meanwhile, when \(C_{B}^{sea}-C_{A}^{sea}=2993.32\) RMB/TEU, Vladivostok Port has the lowest profit. When \(C_{B}^{sea}-C_{A}^{sea}>2993.32\) RMB/TEU, the profit of Vladivostok Port increases with the increase in \(C_{B}^{sea}-C_{A}^{sea}\), while when \(C_{B}^{sea}-C_{A}^{sea}<2993.32\) RMB/TEU, the profit of Vladivostok Port decreases with the increase in \(C_{B}^{sea}-C_{A}^{sea}\). Figure 6: The change in port equilibrium cargo demand with the maritime transportation cost difference. In addition, when \(C_{B}^{sea}-C_{A}^{sea}<-29.7\) RMB/TEU, the profit of Vladivostok Port will exceed that of Dalian Port, and when \(C_{B}^{sea}-C_{A}^{sea}>-29.7\) RMB/TEU, the profit of Dalian Port will exceed that of Vladivostok Port. This means that only if the maritime transportation cost of Vladivostok Port can save \(-29.7\) RMB/TEU compared with Dalian Port, its profit can exceed Dalian Port. 2.3 Sensitivity Analysis of Cross-Border Land transportation Cost and Maritime Transportation Cost to Port Equilibrium Profit  
Figure 8 shows the port equilibrium profit as the cross-border transportation cost and maritime transportation cost difference. It can be seen that on the whole, with the simultaneous increase in \(C_{bB}^{land}\) and \(C_{B}^{sea}-C_{A}^{sea}\), the profits of Dalian Port and Vladivostok Port also increase, and the profit of Dalian Port increases faster than that of Vladivostok Port. However, when \(C_{bB}^{land}\) and \(C_{B}^{sea}-C_{A}^{sea}\) decline at the same time, the profit of Dalian Port declines faster than that of Vladivostok Port. When \(C_{bB}^{land}\) and \(C_{B}^{sea}-C_{A}^{sea}\) decline to a certain extent at the same time, the profit of Dalian Port will be less than that of Vladivostok Port to a certain extent. When the cost of cross-border transportation to Vladivostok Port is higher, and the maritime transportation cost of Vladivostok Port is higher than that of Dalian Port, the cost for shippers to choose Vladivostok Port for cargo transportation will increase. The substitution between Vladivostok Port and Dalian Port will decrease, and the monopoly ability of the two ports to nearby shippers will be enhanced, so the profits of the two ports also increase. Figure 9a illustrates the cross-sectional view of profit change for Dalian Port in Figure 8, considering various \(C_{B}^{sea}-C_{A}^{sea}\): \(-2000\) RMB/TEU, \(-1000\) RMB/TEU, \(0\) RMB/TEU, \(1000\) RMB/TEU, and \(2000\) RMB/TEU. It can be seen that the profit of Dalian Port increases with the increase in \(C_{bB}^{land}\), and the larger the value of \(C_{B}^{sea}-C_{A}^{sea}\), the greater the profit growth of Dalian Port. Figure 9b illustrates the cross-sectional view of profit change for Vladivostok Port in Figure 8, considering various \(C_{B}^{sea}-C_{A}^{sea}\): \(-2000\) RMB/TEU, \(-1000\) RMB/TEU, \(0\) RMB/TEU, \(1000\) RMB/TEU, and \(2000\) RMB/TEU. It can be seen that when \(C_{B}^{sea}-C_{A}^{sea}\) is negative (\(C_{B}^{sea}-C_{A}^{sea}\)=\(-2000\) RMB/TEU, \(-1000\) RMB/TEU), the profit of Vladivostok Port decreases first and then increases with the increase in \(C_{bB}^{land}\). When \(C_{B}^{sea}-C_{A}^{sea}\geq 0\) (\(C_{B}^{sea}-C_{A}^{sea}\)=0 RMB/TEU, \(2000\) RMB/TEU, \(1000\) RMB/TEU), the profit of Vladivostok Port increases with the increase in \(C_{bB}^{land}\).