# Hybrid Early Warning System for Rock-Fall Risks Reduction
## 5 Results and Discussion
### Detection Model Results  
This section illustrates the experimental results of the proposed detection model. First, the eastern mountains of the Aqbat-Sha'ar were chosen as a test site to verify the model's ability to detect the falling rocks and to track rock movement. Then, the platform was installed at a distance of twenty meters away from the mountain. Next, the test was carried out during two time periods, morning and evening. A set of fifteen differently sized rocks were used as test materials to evaluate the proposed model performance. Figure 11 presents images of test rocks divided into five groups (A, B, C, D, E), each group containing three rocks of similar sizes and a unique code. Column four of Tables 3 and 4 contain the disappearance frequency N, the number of pixels in which the rock contour center disappeared from video frames until the fall reached the ground. Figure 11: Sample rocks for testing. Column four of Tables 3 and 5 contains the traceability values, assessing the model's ability to track objects. It depends on disappearance frequency, as described in Equation (13). \[\text{Traceability}=1-\frac{\text{Disappearance}\text{Frequncy}}{\text{Field of view height in pixels}} \tag{13}\] \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Rock Code**} & \multicolumn{2}{c}{**Rock Size**} & \multirow{2}{*}{**Detect Object**} & \multicolumn{2}{c}{**Disappearance**} & \multirow{2}{*}{**Traceability**} \\  & **cm\({}^{3}\)** & & & & \\ \hline A1 & 24.53 & 0 & – & 0.0000 \\ A2 & 37.06 & 0 & – & 0.0000 \\ A3 & 49.00 & 0 & – & 0.0000 \\ B1 & 160.93 & 1 & 22 & 0.9450 \\ B2 & 196.25 & 1 & 20 & 0.9500 \\ B3 & 184.00 & 1 & 20 & 0.9500 \\ C1 & 382.68 & 1 & 16 & 0.9600 \\ C2 & 508.32 & 1 & 14 & 0.9650 \\ C3 & 657.04 & 1 & 13 & 0.9675 \\ D1 & 1052.97 & 1 & 11 & 0.9725 \\ D2 & 1012.00 & 1 & 11 & 0.9725 \\ D3 & 1235.05 & 1 & 11 & 0.9725 \\ E1 & 1880.49 & 1 & 9 & 0.9775 \\ E2 & 2297.01 & 1 & 7 & 0.9825 \\ E3 & 3041.87 & 1 & 6 & 0.9850 \\ \hline \hline \end{tabular}  
* 1 = rock detected, 0 = rock undetected, = unknown values.  
\end{table} 
Table 4: System response in the evening (13:00 to 18:30). \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Rock Code**} & \multicolumn{2}{c}{**Rock Size**} & \multirow{2}{*}{**Detect Object**} & \multicolumn{2}{c}{**Disappearance**} & \multirow{2}{*}{**Traceability**} \\  & **cm\({}^{3}\)** & & & & \\ \hline A1 & 24.53 & 0 & 0 & 0.0000 \\ A2 & 37.06 & 1 & 21 & 0.9475 \\ A3 & 49.00 & 1 & 15 & 0.9625 \\ B1 & 160.93 & 1 & 14 & 0.9650 \\ B2 & 196.25 & 1 & 12 & 0.9700 \\ B3 & 184.00 & 1 & 12 & 0.9700 \\ C1 & 382.68 & 1 & 10 & 0.9750 \\ C2 & 508.32 & 1 & 7 & 0.9825 \\ C3 & 657.04 & 1 & 6 & 0.9850 \\ D1 & 1052.97 & 1 & 5 & 0.9875 \\ D2 & 1012.00 & 1 & 5 & 0.9875 \\ D3 & 1235.05 & 1 & 4 & 0.9900 \\ E1 & 1880.49 & 1 & 3 & 0.9925 \\ E2 & 2297.01 & 1 & 3 & 0.9925 \\ E3 & 3041.87 & 1 & 2 & 0.9950 \\ \hline \hline \end{tabular}  
* 1 = rock detected, 0 = rock undetected, = unknown values.  
\end{table} 
Table 3: System response in the morning (06:00 to 12:00). \begin{table}
\begin{tabular}{c c} \hline \hline \multicolumn{1}{c}{**Parameter**} & \multicolumn{1}{c}{**Value**} \\ \hline Driver reaction time & 0.4 to 2 s \\ Brake Engagement time & 2 s \\ Average acceleration & 10 m/s\({}^{2}\) \\ Average vehicle lengths & 5.4 m \\ Average number of vehicles driving on the road every day (NV) & 6245 vehicles \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Simulation setups. During the testing process, fifteen differently sized rocks were used. The rocks were dropped separately from a height of 22 m, and the results of the system's response are recorded in Table 5.  
The system's ability to detect objects was evaluated by two values, zero or one--zero in the case where no event occurs and one in the case of an event occurring in the field of view. Column three of Table 5 contains the results of the objects' detection. The result shows that the system was able to detect 93.3% of the objects in the morning and 80% in the evening.