# Integrated Digital-Twin-Based Decision Support System for
## 2 Literature Review
### Digital Twin Applications for Modular Construction  
Despite these benefits of RMBs, their relocatability and multi-use lifecycle introduce operational challenges that demand advanced management solutions. Effective logistics management is crucial for ensuring timely delivery, particularly when onsite storage is limited [10]. The need to track, maintain, and reconfigure modules across multiple relocations emphasizes the necessity for advanced management systems capable of addressing these challenges [35]. A DT-based framework offers a promising solution by combining real-time data with virtual models to enable precise monitoring and management throughout the lifecycle of RMBs.  
Recent research on DT applications in MC has primarily focused on facility management, fault detection, and emissions monitoring. [PERSON], [PERSON] [36] explored DT applications in the prefabrication supply chain, demonstrating effective methods for advancing intelligent building processes while monitoring emissions. Similarly, [PERSON], [PERSON] [37] proposed an IoT-enabled BIM platform for the real-time supervision of prefabricated housing construction and cost information analysis. From RFID and GPS, location data can be connected with BIM to activate tracking functions with VR technologies. The proposed platform provides efficiency and decision support in the daily operation of the prefabricated assembly process [37]. [PERSON] and [PERSON] [10] developed a DT system dedicated to monitoring logistics operations related to prefabricated module transportation. This system integrates BIM, IoT sensors, and GISs to simulate logistical operations, predict risks, and calculate accurate estimated times of arrival (ETAs) for modules. By employing tools such as the Unity game engine and Bing Maps, the framework optimizes route scheduling and mitigates potential logistics risks, significantly improving the overall project performance.  
Moreover, DT-based systems have been successfully applied in predictive maintenance and geometric quality assessments in MC. [PERSON], [PERSON] [38] utilized DT technology to assess prefabricated facade quality, comparing as-built lidar scans with as-designed BIM models to evaluate accuracy and completeness. In addition, [PERSON], [PERSON] [39] introduced an integrated DT with BIM, IoT, and GPS for post-occupancy evaluations, ensuring the continuous monitoring of building performance through 4D visualization tools.  
These studies showcase the versatility and potential of DT-based frameworks in enhancing decision making and logistics efficiency in MC. However, existing DT applications predominantly focus on permanent modular structures or single-location projects. In addition, they typically emphasize the static aspects of MC and do not fully address the crucial factor of relocatability inherent to the sector. There is a notable research gap in  
Figure 1: Construction processes of general MC projects and RMBs.  
dedicated solutions for the unique relocatability logistics required for RMBs, including tracking, reconfiguration, and redeployment across multiple sites. To address these gaps, this research proposes to develop and utilize a DT platform specifically designed to support the relocatability logistics of modular buildings. This will involve creating a sophisticated management system that enables the effective real-time monitoring and management of prefabricated module units throughout their lifecycle. This research is expected to advance the field by providing a practical solution to improve RMB resource allocation, enhance lifecycle efficiency, and support sustainable construction practices.