# Digital Twin Framework for Road Infrastructure Management
## 4 Digital Twin Framework for Road Infrastructure Management
### Deriving Layers for the Digital Twin Framework for Road Infrastructure Management  
In the previous section, we reviewed and analyzed DT layer structures and their key components across various domains, including road infrastructure, bridges, tunnels, and other civil infrastructures and urban DTs. Our analysis revealed that while DT layer structures are generally similar, the naming conventions differ across studies. To develop a DT framework for managing road infrastructure, it is necessary to define a standardized set of DT layers. To this end, we generalized the DT layers by comparing and analyzing their definitions and functions as presented in each study. Through this process, five layers were identified and organized as follows: the data acquisition and transmission layer; the data processing, integration, and storage layer; the data/digital modeling layer; the data analysis/analytics layer; and the service/application layer. Table 5 presents these generalized DT layers along with their corresponding names, synthesized based on shared or similar meanings. Duplicate layer names were excluded from the list to maintain uniqueness, although the associated references were retained. \begin{table}
\begin{tabular}{c c c} \hline \hline
**DT Layers** & **Identified Layer Names with Similar Meaning** & **References** \\ \hline \multirow{8}{*}{Data acquisition and transmission layer} & \(\bullet\) & Physical layer \\  & \(\bullet\) & Data acquisition and preprocessing layer \\  & \(\bullet\) & Structural monitoring \\  & \(\bullet\) & Data acquisition layer \\  & \(\bullet\) & Transmission layer \\  & \(\bullet\) & Monitoring and reality capture layer \\  & \(\bullet\) & Data and need acquisition \\  & \(\bullet\) & Sensor data transmission \\  & \(\bullet\) & Communication \\  & \(\bullet\) & Inspection \\  & \(\bullet\) & Data collection layer \\  & \(\bullet\) & Data transfer layer \\  & \(\bullet\) & Real tunnel scene \\  & \(\bullet\) & Observable asset model \\  & \(\bullet\) & Communication interface \\  & \(\bullet\) & Smart asset layer \\  & \(\bullet\) & Communication/transmission layer \\  & \(\bullet\) & Infrastructure layer \\  & \(\bullet\) & Sensor and tag layer \\ \hline \multirow{8}{*}{Data processing, integration, and storage layer} & \(\bullet\) & Database layer \\  & \(\bullet\) & Data structuring and integration layer \\  & \(\bullet\) & Data acquisition and storage \\  & \(\bullet\) & Storage layer \\  & \(\bullet\) & Data processing layer \\  & \(\bullet\) & Data management layer \\ \cline{1-1}  & \(\bullet\) & Data integration layer \\ \cline{1-1}  & \(\bullet\) & Data preprocessing and storage layer \\ \cline{1-1} layer & \(\bullet\) & Data preprocessing, data transfer, and storage \\ \cline{1-1}  & \(\bullet\) & Twin data fusion layer \\  & \(\bullet\) & Twin data layer \\  & \(\bullet\) & Semantic web layer \\ \cline{1-1}  & \(\bullet\) & Data/model integration layer \\ \cline{1-1}  & \(\bullet\) & Smart asset integration layer \\ \cline{1-1}  & \(\bullet\) & Data management \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Derived DT layers for the proposed DT framework.