# Analysis of Research Hotspots and Trends in Confined-Space Work Safety Based on CiteSpace
## 3 Results
### Research Hotspots  
#### 3.6.1 Keyword Co-Occurrence Analysis  
In a keyword co-occurrence map, keywords frequently appearing in a research field can indicate the development trends within that field over a specific period [45]. The keywords from both the Chinese and English-language literature were analyzed, as shown in Figures 6 and 7. In these maps, the size of a node represents the frequency of the keyword's appearance in the literature, the links between nodes indicate connections between the keywords, and the thickness of the lines reflects the strength of these associations. The color variation of the nodes corresponds to the appearance time of the keywords, with purple indicating the earliest appearances and yellow indicating the latest. In the Chinese literature analysis map, there are 297 nodes and 757 connecting lines, with a density of 0.0172. In contrast, the English literature analysis map contains 339 nodes and 1224 connecting lines, with a density of 0.0214. The relatively low network density in the Chinese literature suggests weaker correlations between keywords.  
Figure 6: Keyword co-occurrence in the Chinese literature.  
The high-frequency keywords in the Chinese and English literature were analyzed. In addition to \"limited space\", \"confined space\", and \"enclosed space\", the top ten keywords with the highest frequency were listed, and their centrality was calculated. A node centrality greater than 0.1 indicates that the keyword is a central node, highlighting its importance or influence within the literature network, often due to high connectivity or frequent citations by other nodes. As shown in Table 4, the keyword with the highest frequency in the Chinese literature is \"safety management\", appearing 51 times, with a centrality of 0.17, signifying that it is the focus of research in the field of confined-space work safety in China. In the English literature, the most frequent keyword is \"safety\", which appears eight times but has a centrality of only 0.09. Keywords with high centrality in the English literature include \"occupational safety\", \"management\", and \"design\". This indicates that the focus of foreign research aligns with China's emphasis on occupational safety and management. However, \"design\" appears more frequently in the foreign literature, suggesting that foreign researchers are enhancing work safety through the design of knowledge-based confined-space solutions [44; 45; 46].  
\begin{table}
\begin{tabular}{c c c c c c} \hline
**No.** & \multicolumn{2}{c}{**Chinese Keyword Analysis**} & \multicolumn{2}{c}{**English Keyword Analysis**} \\ \hline  & Keywords & Frequency & Centrality & Keywords & Frequency & Centrality \\ \hline
1 & Safety management & 51 & 0.17 & Safety & 8 & 0.09 \\ \hline
2 & Safety & 19 & 0.05 & Occupational safety & 5 & 0.39 \\ \hline
3 & Accident & 16 & 0.04 & Management & 5 & 0.18 \\ \hline
4 & Work & 15 & 0.04 & Design & 5 & 0.18 \\ \hline
5 & Emergency rescue & 12 & 0.05 & Risk assessment & 4 & 0.02 \\ \hline
6 & Poisoning & 10 & 0.04 &
\begin{tabular}{c} Occupational health \\ and safety \\ \end{tabular} & 3 & 0.03 \\ \hline
7 & Work safety & 9 & 0.02 & Model & 3 & 0.07 \\ \hline
8 & Safety measure & 9 & 0.04 & Risk analysis & 3 & 0.04 \\ \hline
9 & Test & 9 & 0.01 & Fatality & 3 & 0.02 \\ \hline \end{tabular}
\end{table}
Table 4: Analysis of the top ten keywords appearing in the Chinese and English literature.  
Figure 7: Keyword co-occurrence in the English-language literature.