## 6 Thematic Taxonomy of UWSNs
### Applications
#### Defense and Disaster Prevention Application  
Military and defense applications use a combination of underwater sensors to identify potential enemies earlier by conducting ports and harbor monitoring and control [112], sea mine detection [113], border protection from illegal battleships or submarines, and distributed tactical surveillance [114]. Furthermore, UWSN advanced technologies such as the mobile underwater sensor network are also used to provide early warnings of natural catastrophes such as seismic activities on the seafloor [112]. [PERSON] and [PERSON] [115] designed a model for real-time tsunami prediction and used data collected from the occurrence of the tsunami that hit the Indian Ocean in 2004 for evaluation.  
Table 7 shows the implementation of recent studies in various networks and settings. Overall, communication between nodes is achieved using acoustic waves or a combination of both radio frequency waves and acoustics. The network settings are constructed based on the type of application, region, network size, water depth, communication type and frequency, distance between nodes, type of sensor and the total of nodes.  
\begin{table}
\begin{tabular}{l l l l l l l l l l} \hline \hline \multirow{2}{*}{**Reference**} & \multirow{2}{*}{**Application**} & \multicolumn{4}{c}{**Network Deployment**} & \multicolumn{4}{c}{**Communication**} & \multicolumn{2}{c}{**Sensor Node**} \\ \cline{3-10}  & & **Salinity Level** & **Network size** & **Operable Depth** & **Channel Frequency** & **Type** & **Type** & **Distance** & **Number** \\ \hline
[116] & Fish farm & Ocean & Up to 2.4 km & 30 m & 26.8 kHz & RF, Acoustic & Static & 6 m & 5 \\ \hline
[117] & River Monitoring & River & 5000 m \(\times\) 200 m & 50 m & 35 kHz & Acoustic & Mobile & 300 m & 2 \\ \hline
[118] & Ocean Monitoring & Shallow Water & 90 \(\times\) 38 \(\times\) 45 cm & Up to 3 m & 433 MHz & RF, Acoustic & Static & 15 cm & 2 \\ \hline
[119] & Environmental Monitoring & Sea & Up to 2 km & 2 m & 28 kHz & RF, Acoustic & Static & 100 m & 3 \\ \hline
[120] & Water Quality & Sea & 4500 to 5500 m\({}^{3}\) & 45 m & 250 to 400 kHz & RF, Acoustic & Static & 110 m & 3 \\ \hline
[121] & Surveillance & Sea & 23 km \(\times\) 30 km \(\times\) 300 m & 50 m & 1 kHz to 4 kHz & Acoustic & Mobile & 75 m & 2 \\ \hline
[122] & Target Tracking & Sea & Up to 1 km & 32 m & 2 kHz & Acoustic & Mobile & 300 m & 2 \\ \hline
[123] & Exploration & Sea & 14.5 m \(\times\) 12 m & 2 m & 2 kHz & Acoustic & Mobile & 10 m & 3 \\ \hline
[124] & Survey Planning & Sea & 600 m \(\times\) 600 m & 20 m & 1 kHz to 4 kHz & Acoustic & Mobile & 10 m & 2 \\ \hline
[125] & Target Tracking & Sea & 30 m \(\times\) 30 m \(\times\) 25 m & 25 m & 2 kHz & Acoustic & Mobile & 4 m & 6 \\ \hline
[126] & Surveillance & Sea & 400 m \(\times\) 400 m \(\times\) 400 m & 20 m & 3 kHz & RF, Acoustic & Static & 20 m & 4 \\ \hline
[127] & Surveillance & Ocean & Up to 3 km & 90 m to 98 m & 25.6 kHz & RF, Acoustic & Static, Mobile & No Info & 7 \\ \hline
[128] & Exploration & Sea & 600 m \(\times\) 900 m & Up to 80 m & 3 kHz & Acoustic & Mobile & 75 m & 2 \\ \hline
[129] & Ocean Sampling & Ocean & 500 m \(\times\) 500 m & 10 m & 2 kHz & Acoustic & Mobile & 10 m & 2 \\ \hline \hline \end{tabular}
\end{table}
Table 7: Comparison of Various Underwater Wireless Sensor Networks.