# PDCA 4.0: A New Conceptual Approach for Continuous Improvement in the Industry 4.0 Paradigm
## Appendix A Description of the I4.0 Technological Concepts Considered in This Study  
Internet of Things [IoT]--The technological concept \"IoT\" refers to a network characterized by physical devices capable of connecting to the wireless internet. The base components are made up of built-in electronics, such as sensors and transmission hardware. It allows for the rapid generation of data, leveraging the information flow within an organization through physical devices capable of interacting with each other and with control systems, through a network infrastructure [42; 43; 93]. Cyber-physical Systems [CPS]--According to several authors [36; 94; 95] \"IoT and CPS\" should be divided into two different concepts, differing from the categorisationpresented by [PERSON] et al. [44]. The technological concept \"CPS\" refers to systems capable of combining computational modelling, statistical data and physical data in real-time. The physical devices (machines or production lines) and the physical processes are digitized, creating a digital system identical to the physical system [43]. Big Data [BigData]--Some authors, such as [PERSON] et al. [43], separate Big Data from data analytics. However, both concepts are interdependent, and that is why many authors [40; 41; 44] choose not to separate them. The technological concept \"Big Data\" refers to this large data volume [41] and to the technologies of its collection, processing, provisioning, and analysis [44]. This concept is necessary in order to generate factory digital twins [43]. Data analysis refers to data mining, machine learning [43], statistical analysis, and predictive analysis, among others [40]. Regarding cybersecurity, some authors consider it as a separate category [12]. However, there are approaches who do not find it reasonable to approach this concept in an elementary way [40; 44]. Following this last choice, and since cybersecurity technologies are associated with data and information, they are now included in the technological concept of Big Data. Cloud [Cloud]--The technological concept \"Cloud\" is unanimously adopted by other authors, such as [40], with similar descriptions and associated technologies. This concept refers to any IT services provisioned and accessible from a cloud computing provider [41]. It consists of three IT combinations: internet services, web-based applications, and information management [44]. Sensors and Actuators [Sens&Act]--The logic behind this clustering follows the work by [PERSON] et al. [41], which is entitled \"Sensors and Actuators\" instead of simply \"Sensors\". Additionally, [PERSON] et al. [44] do not address actuators in their article, while other authors [41; 43] argue that it is an important topic to be included. This technological concept \"Sens&Act\" includes basic technologies for the digitalization of objects and physical parameters [43]. It includes all devices that respond to a physical stimulus and transmit a resulting impulse [41]. This concept is also associated with RFID (radio frequency identification) [41]. Autonomous Robotics [AutRob]--This technological concept includes autonomous, collaborative, and intelligent robots and equipment, with embedded sensors, dexterity, artificial intelligence, and machine learning [44]. As there is no common line in the literature about the place of artificial intelligence and machine learning, the present classification follows the same choice of [PERSON] et al. [44] of having just one technological concept (AutRob) where all of these associated technologies are included. Simulation and Virtualization [[PERSON]&[PERSON]]--This technological concept includes virtual tools that provide support to the decision-making process. In this scope, assisted reality (AsR), augmented reality (AR), and virtual reality (VR) are emerging technologies that create partial and complete virtual environments, capable of enhancing tasks and speeding up training [43]. [PERSON] et al.