# Location Optimization of Emergency Bell Based on Coverage Analysis for Crime Prevention
## 4 Results and Discussion
### Result of K-Means Cluster Analysis  
After reducing the number of variables using PCA, the K-means clustering method was employed to analyze the data. A group of administrative dongs with high values for both the number of bells and crime was derived as a high-level cluster from K-means clustering, as shown in Figure 5.  
According to Table 5, Suwan-dong was found to have the highest number of emergency bells and CCTV cameras installed. While there was a high demand for CCTV cameras in \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**District**} & \multirow{2}{*}{**Population**} & \multirow{2}{*}{**Area (km\({}^{2}\))**} & **Population** & **Number of** & **Number of** & **Number of** \\  & & & **Density per** & **Emergency** & **Emergency Bells per** & **Emergency Bells** \\  & & & **1 km\({}^{2}\) * & **Bells** & **10,000 People ** & **per 1 km\({}^{2}\) *** \\ \hline East & 105,077 & 49.31 & 2130.95 & 272 & 25.89 & 5.52 \\ West & 292,837 & 47.76 & 6131.43 & 492 & 16.80 & 10.30 \\ South & 217,032 & 60.99 & 3558.48 & 355 & 16.36 & 5.82 \\ North & 431,587 & 120.27 & 3588.48 & 600 & 13.90 & 4.99 \\ Gwangsan & 416,012 & 222.79 & 1867.28 & 598 & 14.37 & 2.68 \\ Total & 1,462,545 & 501.12 & 2918.55 & 2317 & 15.84 & 4.62 \\ \hline \hline \end{tabular}  
* Population density per 1 km\({}^{2}\) (people): population/area; ** Number of emergency bells per 10,000 people (number): (number of emergency bells/population) \(\times\) 10,000; ** Number of emergency bells per 1 km\({}^{2}\): (number of emergency bells/area).  
\end{table} 
Table 4: Spatial characteristics of emergency bell installation by district. the area, further examination revealed that Suwan-dong had a high volume of transient population during the daytime (07:00-17:00) and was also one of the districts with a high crime rate. Meanwhile, Hanam-dong, which had the highest volume of transient population during the daytime, was found to be the district with the second-highest number of emergency bells and CCTV cameras, as the transient population during the daytime had a high correlation with the number of emergency bells and CCTV cameras. Furthermore, Chipyung-dong was identified as an area where crime occurred most frequently among the high-level cluster. Despite having a relatively high number of emergency bells and CCTV cameras in the cluster, the surveillance area received a rating of 0.29, which was relatively low considering the number of crimes committed in the area. Although the number of installation requests for CCTV cameras is the lowest among administrative dongs in the upper cluster, it is still important to consider additional installations of emergency bells and CCTV cameras. Yongbong-dong was the district with the third highest crime occurrence, following Chipyung-dong and Suwan-dong. Despite the high crime rate of Yongbong-dong, it had the lowest number of emergency bells and CCTV cameras installed among high-ranking clusters. This suggests a potential need to consider installing additional emergency bells or CCTV cameras. In summary, the analysis of the high-level cluster revealed variations in the installation of emergency bells and CCTV cameras among different administrative dongs. Some districts had a need for these systems more urgently due to their higher crime rates and larger transient populations. However, other factors, such as age demographics, may have also played a role in the implementation of these security measures. Additional research could offer valuable insights into the efficacy of security systems and help pinpoint areas where supplementary installations could bolster public safety. Employing a clustering technique based on K-means, determining the optimal locations for the top clusters corresponding to administrative districts was considerable. However, restricting the optimal location solely to administrative districts would result in too limited of a scope. Therefore, this study conducted an analysis encompassing the entire city of Gwangju to identify the optimal placement of emergency bells.