## 2 Background
### Driving Technologies of Industry 4.0  
To create or implement smart factories, the use of digital technologies is necessary, as they are considered drivers for the development of Industry 4.0 and essential for industrial operation [60]. Therefore, Table 2 aims to present the driving technologies of Industry 4.0, as well as the authors who have cited each of these technologies.  
\begin{table}
\begin{tabular}{p{142.3 pt} p{142.3 pt}} \hline \hline \multicolumn{1}{c}{**Definitions**} & **Reference** \\ \hline Industry 4.0 utilizes the integration of the manufacturing production system with the digital revolution, artificial intelligence, the Internet of Things, and all intelligent devices, aiming for greater efficiency. & [48] \\ \hline It indicates the use of digitization and integration of manufacturing and logistics processes, as well as the use of the Internet and smart devices. & [54] \\ \hline It relates to a variety of technologies that enable the development of the value chain, aiming to reduce manufacturing lead times and, consequently, improve the quality of products and processes, as well as organizational performance. & [55] \\ \hline It refers to a model of convergence of nanotechnology, biomedicine, information technology, and cognitive science, encompassing the fusion between the physical, real, and digital worlds. & [56] \\ \hline It corresponds to the integration of digital systems to monitor physical systems, integrating digital technologies throughout the production process. & [57] \\ \hline It corresponds to the digitization of production processes with sensors and information systems, aiming to make processes more efficient. & [12] \\ \hline It involves the use of the Internet to integrate machines, electronic devices, sensors, and people. & [58] \\ \hline It indicates the adoption of new technologies in all economic spheres, seeking a digital ecosystem through the integration of all production systems and components. & [59] \\ \hline \hline \end{tabular}
\end{table}
Table 1: Definitions of Industry 4.0.  
It is observed from Table 2 that 14 driving technologies of Industry 4.0 have been identified through a systematic literature review. Each of these technologies has particularities and importance for Industry 4.0, and their correct implementation can result in more agile processes, cost, and loss reduction, leading to automation of part of the production process, often controlled by intelligent real-time systems [86]. Before discussing the meaning of each of them, Figure 2 illustrates each of these 14 technologies.  
\begin{table}
\begin{tabular}{c c} \hline
**Driving Technologies** & **Reference** \\ \hline Big Data & [2,7,9,19,24,38,48,55,57,58,61,62,73] \\ \hline Blockchain & [2,62,69,71,72,74,75] \\ \hline Cloud Computing & [2,7,9,19,28,29,38,55,58,61,62,64,66,67,68,70,71,76,77,78,79,81] \\ \hline Cyber–Physical System (CPS) & [9,13,24,48,58,62,68,79,80,82,82,83,84,85,86,87,88,89,81,82,83,84,86,87,88,88] \\ \hline Cybersecurity & [2,19,38,55,57,61,64,66,67,68,68] \\ \hline Artificial Intelligence (AI) & [29,69,71,75,81] \\ \hline Internet of Things (IoT) & [2,3,7,9,12,19,28,38,48,55,57,58,61,62,64,66,75,77,79,81,83,88,89] \\ \hline Industrial Internet of Things (IIoT) & [7,12,19,59,65,70,88] \\ \hline Machine Learning & [64,90] \\ \hline Additive Manufacturing (3D Printing) & [2,9,19,38,55,57,61–64,66–68,72,73,79,81] \\ \hline Radio Frequency Identification (RFID) & [3,7,58,62,63,67,72,75,81] \\ \hline Augmented/Virtual Reality & [2,9,19,38,55,57,61,64,66–68] \\ \hline Autonomous Robots & [2,19,38,48,55,57,58,61,64,66–68,71,81,86,91] \\ \hline Simulation & [19,38,48,55,57,61,64,66–68] \\ \hline \end{tabular}
\end{table}
Table 2: Table of authors’ driving technologies of Industry 4.0.  
Figure 2: Driving technologies of Industry 4.0.