## 2 Literature Review
### Benefits and Challenges of Digital Twins  
#### 2.2.1 Benefits of Digital Twins  
Regarding the potential benefits of DTs in various contexts, the growing application of DTs across multiple fields can be attributed to their significant practical advantages. For example, in 2019, Oracle reported eight key benefits of implementing DTs, which are categorized as follows: better efficiency and safety, scenario evaluation and risk assessment, predictive maintenance and scheduling, improved decision-making systems, real-time remote monitoring and control, the personalization of services and products, strengthened intra- and inter-team collaboration, and better communication and documentation [4]. All of these might contribute to reducing project times and costs during the project life cycle [16].  
In terms of DTs' benefits in the construction industry, [PERSON] [36] identified several key features of DTs technology that are particularly relevant to design and the built environment. These features include BIM, 2D and 3D models, schedules, contracts, construction documents (e.g., submittals, change orders, RFIs), operational data gathered from embedded sensors, and information derived from AI and machine learning technologies. It is essential to note that the relevant studies indicated that the degree of synchronization among these features, whether within a single system or across multiple systems, primarily depends on the effectiveness of the IoT [30]. This synchronization enables operators to access and control various systems, detect faults, and support decision-making processes across different workspaces and their components within the asset.  
Along with the factors mentioned above, it could be concluded that the common DT benefits reported in the construction industry include automated progress monitoring, updated as-built drawings and models, resource planning and logistics, safety monitoring, quality assessments, the optimization of equipment usage, worker monitoring and tracking, facility monitoring, facilities management and operations, enhanced decision-making, and the promotion of sustainable development, as shown in Table 1. An example of DTadoption in the construction industry is General Electric's (GE) implementation of DTs in their wind farms to optimize wind energy production. This initiative led to a notable 20% increase in energy output, generating an additional profit of around USD 100 million [37]. Moreover, research conducted by the McKinsey Global Institute indicates that digital transformation in the construction industry can lead to productivity increases of 14 to 15 percent and cost savings of 4 to 6 percent [38]. Here, it can be inferred that, as Industry 4.0 continues to evolve, further advancements in this domain may result in additional cost savings. Additionally, integrating DTs technology with mobile devices and wearables on construction sites allows for the real-time comparison of a project's as-built and as-designed conditions. This approach improves the accuracy of project representations and significantly reduces errors and reworkings by enabling the timely transmission of up-to-date information to the field [32].