## 2 Research Background  
Nowadays, the accelerated diffusion of digital technologies reveals the importance of studying their effects on SCs [15]. Moreover, SC integration can result in more competitiveness and higher performance. Better integration and monitoring of SC processes by exploiting the digital paradigm enable the reduction of waste and achieve continuous improvement as suggested by the Lean principles [16]. The results of a survey by [17] indicated the inclination of SC members to know about the mutual effects of applying both Lean and digital technologies in SC. Moreover, Lean principles can provide a proper condition to implement Industry 4.0 technologies to increase process efficiency [17; 18]. Furthermore, real-time data provided by Industry 4.0 can assist to use Lean principles in SCs [19]. As a result of the relationship that can be hypothesized between Industry 4.0 and Lean Manufacturing, previous research argued that the compatibility of the two notions should be investigated in more detail. In fact, understanding how and when Lean principles and digital technologies can be combined together is a strategic decision for the SC members [17; 20]. At the first step, identifying and determining the definition of different Industry 4.0 technologies can help to have a better perception of them. Therefore, Table 1 describes the definition of all digital technologies that were included in the Industry 4.0 concept. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Industry 4.0 Technology** & **Definition** & **Reference** \\ \hline \multirow{4}{*}{Augmented Reality (AR)} & AR is a potential technology to assist employees by enlarging the real world by providing additional information from different sources and types such as text, video, sound, and even smell. & [21; 22] \\ \cline{2-3}  & Storage, sharing, and easy access to the data remotely and on-demand based on the competitive costs and according to the customer requirements. & [22; 23] \\ \hline \multirow{4}{*}{Robotics (R)} & Applying automatic robots to complete tasks automatically or in collaboration with humans to provide more flexibility and safety in workplaces. & [24] \\ \hline \multirow{4}{*}{Sensor Technology (ST)} & Enabling checking, monitoring, and controlling different internal and external activities related to the products. Its capabilities are range from sensing the quality status to the other applications in the shop floor and life cycle assessment. & [21; 23] \\ \cline{2-3}  & Making a seamless experience for the final customer from shopping in different provided both online and offline channels. & [25] \\ \hline \multirow{4}{*}{Internet of Things (IoT)} & Making the link between objects and information systems to collect real-time data about the location and other features of the object by connecting to the internet systems. & [22; 26] \\ \cline{2-3}  & SDVs are capable to find their way without human intervention by self-navigation and sensing. & [21] \\ \hline \multirow{4}{*}{Unmanned Aerial Vehicles (UAV)} & A flying platform to use for different proposes without the need to pilot and controllable based on predetermined program or remote control. & [21; 27] \\ \cline{2-3}  & Producing customized or urgent needs products from 3D printing models by layer upon layer & \\ \cline{2-3}  & Manufacturing (AM) & procedure from using one source of materials. In this procedure, there is no need for the assembly of parts. & [22; 23] \\ \hline \multirow{4}{*}{Blockchain (BC)} & A secure and safe manner to share and access tamper-proof real-time data among different stakeholders. & [24] \\ \cline{2-3}  & Knowledge extraction by analyzing the huge amount of structured, semi-structured, or unstructured data to facilitate the decision-making process based on the obtained knowledge. & [21] \\ \hline \multirow{4}{*}{Artificial Intelligence (AI)} & Advanced analytical tool for providing better perception about future possible scenarios for different activities and operations in SC.