# Towards Future BIM Technology Innovations: A Bibliometric Analysis of the Literature
## 4 Bibliometric Analysis
### Co-Occurrence Analysis  
The co-occurrence analysis is utilised to provide the main keywords of the collected articles and is based on three units of analysis. However, in this study, the \"all keywords\" unit of analysis is considered. The following settings have been applied in VOSViewer(r) tool: The minimum number of occurrences of a keyword was set to 12. The results indicated that 51 out of 2911 keywords met this threshold. Moreover, a manual normalisation was used to eliminate spelling errors and word repetition to ensure the consistency of the analysis. The final number of keywords was 38, as illustrated in Table 1 and Figure 2. Table 1 reviews the quantitative dimensions of the revealed keywords, which consist of the average publication year, the average citations, and the average normalised citation. The co-occurrence network of keywords generated from the final number of keywords is illustrated in Figure 2. The larger the number of abstracts and titles that have the same two terms in common, the closer these terms to appear in the map [31]. The tool divided the keywords into five clusters, as illustrated in Table 2, of which four out of five will be discussed later in this article (Section 4.2). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Keywords** & **Occurrences** & **Percentage (\%)** & \ \begin{tabular}{c} **Total Link** \\ **Strength** \\ \end{tabular}  & **Avg. Pub. Year** & **Avg. Citation** & \begin{tabular}{c} **Avg. Norm** \\ **Citation** \\ \end{tabular}  \\ \hline BIM & 137 & 11.77 & 120 & 2016 & 8 & 1.09 \\ ontology & 106 & 9.11 & 89 & 2015 & 9 & 0.92 \\ management & 65 & 5.58 & 62 & 2016 & 12 & 1.69 \\ model & 57 & 4.90 & 48 & 2016 & 14 & 1. The average publication year has been examined to detect the recentness of a keyword. For instance, keywords focusing on LS, CC, and AI were published around 2014, which suggests that was when the research community discovered the value and necessity of these technologies to boost the construction industry. Keywords related to interoperability, infrastructure, knowledge management, design, construction, and ontology with a significant appearance of keywords related to LS such as recognition, photogrammetry, and point clouds were circulated in 2015. In 2016, several themes emerged, such as management, performance, safety, reconstruction, prediction, semantic web, knowledge, and optimisa \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Keywords** & **Occurrences** & **Percentage (\%)** & **Total Link Strength** & **Avg. Pub. Year** & **Avg. Citation** & **Avg. Norm Citation** \\ \hline point clouds & 22 & 1.89 & 22 & 2015 & 12 & 1.34 \\ cloud computing & 36 & 3.09 & 16 & 2014 & 11 & 1.14 \\ classification & 23 & 1.97 & 18 & 2016 & 10 & 1.02 \\ simulation & 27 & 2.32 & 24 & 2016 & 10 & 1.58 \\ integration & 15 & 1.28 & 14 & 2016 & 10 & 1.42 \\ semantic web & 21 & 1.81 & 20 & 2016 & 9.5 & 1.35 \\ knowledge & 21 & 1.81 & 19 & 2016 & 9 & 1.04 \\ linked data & 12 & 1.03 & 12 & 2016 & 8 & 1.38 \\ algorithm & 12 & 1.03 & 9 & 2015 & 7.6 & 0.92 \\ machine learning & 36 & 3.09 & 25 & 2017 & 8 & 1.34 \\ information & 36 & 3.09 & 32 & 2016 & 7 & 1.45 \\ technology & 18 & 1.55 & 16 & 2016 & 7 & 1.18 \\ optimization & 17 & 1.46 & 16 & 2016 & 5 & 0.76 \\ architecture & 13 & 1.12 & 10 & 2015 & 5 & 0.62 \\ internet of things & 20 & 1.72 & 15 & 2017 & 4 & 1.12 \\ artificial intelligence & 16 & 1.37 & 7 & 2014 & 3 & 0.20 \\ internet & 12 & 1.03 & 11 & 2017 & 3 & 1.50 \\ big data & 17 & 1.46 & 12 & 2017 & 2 & 1.12 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: \(Cont.\)  
Figure 2: Network visualisation of keywords’ co-occurrence. tion. Moreover, in more recent years, themes such as big data, IoTs, and ML have caught researchers' attention. The average publication year gives an idea of the expansion of mindsets in the research community. For instance, the research field has expanded from focusing on new buildings to focusing on new technologies to create BIM models for existing buildings and topics related to various infrastructures.