## 3 The Significance of Developing Industry 4 Facilities in Academia
### Types of Industry 4 Facilities  
There are two main types of Industry 4 facilities in academia: learning factories and Testlabs. However, it can be seen through the statistics in this literature review that the development of Industry 4 Learning Factories is shown in significantly greater numbers than the Testlab concept implementation.  
Most of the development of learning factories considered the integration of the Industry 4 philosophy as soon as the concept of Industry 4 was proposed in Germany [16]. The framework of learning factories can perfectly fit into the Industry 4 philosophy to build a pilot-scale smart factory. They are used for learning and research purposes, as well as for industrial practices, which gives learning factories great potential to demonstrate the processes of integrating the digital transformation [52; 53]. That is the main reason why Industry 4 learning factories, also known as smart learning factories [54], have become the main type of Industry 4 facility in academia and in industry.  
The Industry 4 learning factories are targeted at facilitating education, research, and relevant vocational training with the aim of demonstrating, developing, and integrating the digital transformation [55; 56]. In particular, Industry 4 learning factories can contribute to academia with a physical environment for undergraduates to conduct interactive workshops, a testbed for higher degree research students to work out novel concepts for their  
Figure 1: PRISMA-style flow diagram of the screening process. The number of articles was screened from 663 down to 145 for the research.  
research and theses, an incubator for industrial participants to conduct collaborative and pilot projects, and a platform for local communities to hold technical events and demonstrations [52; 57; 58; 59]. In addition, some challenges in the traditional teaching paradigm of learning factories, such as unaffordable maintenance costs and rigid teaching strategies, can be mitigated by implementing Industry 4 principles [15].  
In contrast, publications reporting on the development of Industry 4 Testlabs in academia are significantly fewer than learning factories. Nevertheless, it is true that the development of Industry 4 Testlabs has the same goals of pushing Industry 4 transformation in both academia and industries, but with a slightly different focus. [PERSON] et al. [60] developed an Industry 4 Testlab for developing smart robotic assembly strategies. Similarly, [PERSON] et al. [61; 62] demonstrated their preliminary works in developing an Industry 4 laboratory to enable robotic flexible assembly strategies by employing collaborative robots and a digital twin system.  
Both Industry 4 learning factories and Industry 4 Testlabs can offer participants project-based activities for teaching, research, and training purposes. However, Industry 4 learning factories emphasise more on integrating the whole infrastructure of Industry 4 ecosystems to facilitate educational and research activities. In contrast, Industry 4 Testlabs focus more on showcasing the concept and individual technologies at this stage.