## 5 Results  
The general objective of this study was to create an overview of the evolution and current status of the Digital Twin (DT) concept. This encompassed identifying definitions from specialized literature, examining the applicability of DTs in fields such as manufacturing, medicine, smart cities, and education, and presenting some of the available architectures that offer flexibility and adaptability in implementation. Another objective was to identify the advantages, limitations, and challenges resulting from the use of DTs in these fields. The research was conducted in four stages. The first stage focused on understanding the Digital Twin concept. A Google Scholar search for \"Digital Twin definition\" yielded 39,500 results. Starting from the definition given by [PERSON] (2016) [2], five more definitions were selected to provide a clear, complete, and precise understanding of the concept, highlighting aspects applicable in different industries. The selected definitions emphasized the three components of a Digital Twin: the physical product, the virtual product, and the connection between them. The second stage involved identifying sources to classify Digital Twin architectures. A Google Scholar search for \"Digital Twin classification\" yielded 27,100 results. [PERSON] et al. [13] classified Digital Twins according to several parameters, including creation time, integration level, role within the application, focused application parameters, hierarchical structure, and maturity level. This classification helped in understanding the technologies facilitating the development and effective implementation of Digital Twins, as well as their similarities and particularities. \begin{table}
\begin{tabular}{l l} \hline \hline
**Applications of Digital Twins—Fields** & **References** \\ \hline A. Manufacturing & [27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49] \\ \hline B. Medicine & [63; 87; 88; 89; 85; 86; 87; 88; 89] \\ \hline C. Various fields—Smart cities, Energy production, Oil industry, Education & [90; 10; 11; 12; 13] \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The fields of application for DTs. The third stage involved a comprehensive assessment of the advantages, limitations, and challenges associated with the use of Digital Twins. By examining both the benefits and drawbacks, the study provided a balanced perspective on the potential and challenges of adopting Digital Twin technology. The structured approach taken in this study provided a thorough examination of the Digital Twin concept, from definitions and classifications to practical applications and challenges. The insights gained are valuable for academics and practitioners aiming to implement Digital Twin technology effectively across different industries. The systematic analysis and detailed classification offer a robust foundation for future research and development in this dynamic field. Regarding the classification of Digital Twins, six sources were cited to highlight their adaptability to various scenarios built on specific requirements, ensuring effective implementation in a variety of fields and industries. One of the future objectives is the proposal of an architectural framework for the Digital Twin. A Google Scholar search for \"Digital Twin architecture\" yielded 31,100 results. Given the large number of publications, several criteria were established based on which the sources detailed in this work were selected. The criteria focused on how Digital Twins can be structured and managed to ensure interoperability, adaptability, scalability, and security of the systems. Several reference architectures [18; 19; 23] were selected, emphasizing service delivery and adaptability in various domains such as the medical field. For example, the architecture proposed by [PERSON] et al. [23], Digital Twin as a Service (DTaaS), serves as a starting point for real-time patient monitoring and personalized treatment prediction.