# Sound Localization Framework for Construction Site Monitoring
## 7 Results and Discussion  
To verify the CSLF, we determined the ratio of the error values over the course of the test repetitions (Figure 13). The average recall rate in these tests was 83.2% (Table 5). \"Recall\" refers to the proportion of the received experimental values in the entire test results. The main cause for not receiving the result values was the excess load owing to Pi power supply problems and reduced data transmission speeds caused by the wired connections. Figure 12: Geometry of the exterior construction site validation test. Figure 13: Results of the interior construction site validation test 1. The validity verification test 1 results showed that the average differences along the x-, y-, and z-axes were the average differences between the estimated location coordinates and the actual sound-source locations (Table 5). The x-, y-, and z-axes differences were 0.09-0.35, 0.11-0.44, and 0.32-0.41 m with averages of 0.26, 0.27, and 0.36, respectively. The average difference along all axes was less than 0.50 m. Considering the task ranges of construction site workers and the size of the space, this can be considered as an allowable error since it is within the range of an arm of a human being, and hence, people can easily locate the sound source. Additionally, we analyzed the level of distribution of the estimated coordinates from the actual location of the sound source to examine the precision of the test results. A reference distance was used, and the distribution levels for 10% and 5% of the reference distance were calculated (Figure 14). Within 5% and 10% of the reference distance, the distribution was 41.67-59.68% and 69.05-87.95%, with an average of 45.24% and 69.05, respectively (Table 5). In validation test 2, the result recall rate dropped as one moved farther away from the circle, and the error was greater along the y-axis than on the x-axis. When the tests were conducted from points 1 to 3, the recall rate was low, and the sound-source locations could not be estimated accurately (Table 6). However, the estimated coordinate values formed a detection boundary at (7.00, \(-\)4.50, 1.35), as shown in Figure 15. The distance from the array center to the detection boundary was 8.17 m, 1.38 times the radius (5.88 m) of the monitoring circle created by the microphone array. This test was intended to verify the monitoring range, with the experimental radius set to 5.88 m for indoor  
Figure 14: Point-cloud sparsity reference. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Sound-Source**} & \multirow{2}{*}{**Test**} & \multirow{2}{*}{**Recall**} & \multirow{2}{*}{**X Error**} & \multirow{2}{*}{**Y Error**} & \multirow{2}{*}{**Z Error**} & \multicolumn{2}{c}{**Point-Cloud Distribution Rate**} \\  & & & & & & & **Less than 10\%** & **Less than 5\%** \\
**Point** & & **(\%)** & & & & & **(\%)** & **(\%)** \\ \hline
1 & 84 & 88 & 0.24 & 0.42 & 0.32 & 69.05 & 45.24 \\
2 & 79 & 94 & 0.09 & 0.40 & 0.35 & 75.95 & 44.30 \\
3 & 72 & 86 & 0.09 & 0.44 & 0.33 & 70.83 & 41.67 \\
4 & 109 & 89 & 0.13 & 0.43 & 0.39 & 77.06 & 47.71 \\
5 & 64 & 78 & 0.19 & 0.41 & 0.40 & 71.88 & 46.88 \\
6 & 80 & 92 & 0.35 & 0.11 & 0.31 & 83.33 & 50.00 \\
7 & 76 & 63 & 0.32 & 0.14 & 0.35 & 83.78 & 48.65 \\
8 & 72 & 68 & 0.35 & 0.18 & 0.33 & 76.39 & 43.06 \\
9 & 85 & 70 & 0.30 & 0.22 & 0.41 & 87.95 & 51.81 \\
10 & 60 & 85 & 0.23 & 0.27 & 0.38 & 78.33 & 58.33 \\
11 & 73 & 84 & 0.35 & 0.16 & 0.33 & 82.19 & 50.68 \\
12 & 79 & 85 & 0.34 & 0.11 & 0.38 & 82.28 & 46.84 \\
13 & 67 & 95 & 0.35 & 0.19 & 0.35 & 79.10 & 47.76 \\
14 & 79 & 90 & 0.34 & 0.25 & 0.34 & 82.28 & 46.84 \\
15 & 62 & 81 & 0.23 & 0.28 & 0.36 & 80.65 & 59.68 \\ Average for 1141 repetitions & 83.20 & 0.26 & 0.27 & 0.36 & 69.05 & 45.24 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Results of the interior construction site validation test 1.  
space sizes and a stable driving system.