# Multi-Agent Simulation Approach for Modular Integrated Construction Supply Chain
## 3 Proposed Agent-Based Model
### From Physical Process to the Multi-Agent Model  
The physical process in Figure 2(a) begins with the suppliers who produce prefabricated components such as beams, exterior walls, and laminated boards. These components are manufactured in suppliers' plants, which are designed to handle large-scale production with high precision. Once produced, these components are transported by transporters (\(T_{1}\)) to the MiC factories. At these factories, the prefabricated components are assembled into integrated construction modules. This stage involves the assembly of various components into fully functional modules, including the integration of mechanical, electrical, and plumbing systems. The assembled modules are then transported by transporters (\(T_{2}\)) to the construction sites. Finally, at the construction site (\(CS\)), the integrated construction modules are assembled into the final structure. This on-site assembly is significantly faster than traditional construction methods, reducing overall project timelines and minimizing the impact of on-site activities. The intermediate layer between the physical process and the multi-agent simulation model in Figure 2(b) is crucial for capturing real-time information and ensuring the accuracy of the simulation model. Various technologies are employed to collect and manage data:  
* Inventory System: Tracks the availability and status of prefabricated components in stock at the supplier level. * Geographic Information System (GIS) such as Global Positioning System (GPS) and Open Street Map (OSM) [47]: Provides real-time tracking of transport vehicles, ensuring efficient route planning and the timely delivery of components and modules. \begin{table}
\begin{tabular}{c p{142.3 pt} p{142.3 pt}} \hline \hline
**Study** & **Focus** & **Limitations Addressed** \\ \hline
[38] & Inventory management in OSC & Single supply chain stage, does not address dynamic interactions or uncertainties \\
[39] & Vehicle routing for OSC logistics & Single supply chain stage, lacks integration with other stages and consideration of real-world uncertainties \\
[40] & Integrated truck planning for OSC between different supply chain stages & Single supply chain stage, does not incorporate dynamic interactions between different supply chain stages \\
[41] & Combining production with logistics in OSC & Integrated approach, but overlooks uncertainties and dynamic interactions critical for real-world applications \\
[42] & Integrating logistics with installation in OSC & Holistic approach, but lacks consideration of uncertainties and stakeholder dynamics \\
[43] & DES simulation for OSC logistics & Models complex processes over time but does not fully integrate all supply chain stages or stakeholder dynamics \\
[44; 45; 46] & Multi-method simulation with optimization for MiC & Robust framework addressing dynamic interactions, but further research needed for holistic integration of all supply chain stages \\ This Study & Multi-agent simulation for holistic MiC logistics & Comprehensive integration of all supply chain stages, addressing dynamic interactions, uncertainties, and real-time data integration \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison of related work. * Manufacturing Execution System (MES) [48]: Manages the production process at MiC factories, integrating physical processes with automation and control systems to ensure high-quality module fabrication. * Radio-Frequency Identification (RFID) [49]: Tracks the movement and status of components and modules throughout the supply chain. * Building Information Modeling (BIM) [50]: Provides detailed digital representations of the construction project, enabling the precise planning and execution of the assembly operations for integrated modules. The multi-agent simulation model in Figure 3c uses the data collected to simulate the interactions between different agents in the MiC supply chain. Each agent represents a key entity in the supply chain, including suppliers, transporters, factories, and construction sites.