## 3 Results
### Sensitivity Analysis  
Results of a sensitivity analysis show the impact of different conditions on ranking alternatives (hamlets). Nine scenarios were conducted in connection with 10 selected criteria and 5 decision makers (DMs). Scenarios S\({}_{1-3}\) deal with different groups of decision criteria based on their characteristics (the land-induced criteria (C\({}_{1}\): slope; C\({}_{2}\): terrain elevation; C\({}_{3}\): creek-bottom terrain; C\({}_{4}\): soil type), the water-induced criteria (C\({}_{5}\): stream density; C\({}_{6}\): drainage channel density; C\({}_{7}\): distance to water body), and the anthropogenic-induced criteria (C\({}_{8}\): high tide-induced flooding area; C\({}_{9}\): land use land cover; C\({}_{10}\): water storage by transportation corridors)) corresponding to all five decision makers. Scenarios S\({}_{4-8}\) deal with all 10 criteria corresponding to all five decision makers. Table 6 and Figure 6 shows that fuzzy TOPSIS is more sensitive to the changes of land-induced criteria and the committee of decision makers in different scenarios. The second scenario using slope, \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Goals** & **Criteria** & **Weight** & **Rank** \\ \hline \multicolumn{3}{c}{C\({}_{1}\): Slope} & 0.088 & 9 \\ \hline C\({}_{2}\): Terrain Elevation & 0.123 & 1 \\ \hline C\({}_{3}\): Creek-bottom Terrain & 0.118 & 2 \\ \hline C\({}_{4}\): Soil Type & 0.090 & 8 \\ \hline C\({}_{5}\): Stream Density & 0.098 & 5 \\ \hline C\({}_{6}\): Drainage Channel Density & 0.097 & 6 \\ \hline C\({}_{7}\): Distance to Water Body & 0.103 & 4 \\ \hline C\({}_{8}\): High Tide-Induced Flooding Area & 0.106 & 3 \\ \hline C\({}_{9}\): Land Use Land Cover & 0.085 & 10 \\ \hline C\({}_{10}\): Water Storage by Transportation corridors & 0.092 & 7 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Results of the weight of criteria conducted by fuzzy AHP. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Alternatives** & **Separation from Positive** & **Separation from Negative** & **Closeness** & **Rank** \\ \multicolumn{3}{c}{**(Hamlets)**} & **Ideal Solution (\(d^{+}\))** & **Ideal Solution (\(d^{-}\))** & **Coefficient (CC\({}_{i}\))** & **Coefficient (CC\({}_{i}\))** \\ \hline A\({}_{1}\) (Khuong Binh) & 9.5076 & 0.5273 & 0.0525 & 6 \\ \hline A\({}_{2}\) (Pho Dong) & 9.4685 & 0.5641 & 0.0562 & 4 \\ \hline A\({}_{3}\) (Duong Thanh) & 9.5356 & 0.5014 & 0.0500 & 8 \\ \hline A\({}_{4}\) (Luong Binh) & 9.4449 & 0.5854 & 0.0584 & 3 \\ \hline A\({}_{5}\) (Tu Cung) & 9.4794 & 0.5531 & 0.0551 & 5 \\ \hline A\({}_{6}\) (An Loi) & 9.3614 & 0.6680 & 0.0666 & 1 \\ \hline A\({}_{7}\) (Lac Dien) & 9.4319 & 0.5994 & 0.0597 & 2 \\ \hline A\({}_{8}\) (Thanh Quang) & 9.5159 & 0.5196 & 0.0518 & 7 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The distance values and the final rankings. terrain elevation, creek-bottom terrain, and soil type reflects a small variation between alternatives A\({}_{4}\) (the Luong Binh hamlet) and A\({}_{7}\) (the Lac Dien hamlet) compared to the current case. On the contrary, the differences in the ranking alternatives are very much when using the remaining criteria (water-induced and anthropogenic-induced criteria, C\({}_{5-10}\)) or not using the assessments of all the decision makers. The alternative A6 ranks first in all scenarios which indicates that the An Loi hamlet is consistent with the variation of selected decision criteria and decision makers. Alternatives A\({}_{2}\) (Pho Dong), A\({}_{4}\) (Luong Binh), and A\({}_{7}\) (Lac Dien) change ranking positions, but are always in the group assessed as having the most hazardous flood risk in all scenarios.