# From Cyber-Physical Convergence to Digital Twins: A Review on Edge Computing Use Case Designs
## 6 The Digital Twin Technology
### The Digital Transformation  
Due to the personalized techniques for capturing the dynamics of the physical assets, DT is well known as the major enabler of the digital transformation. In general terms, digital transformation can be defined as the adoption of digital technology and integrating into the business processes of an organization in order to fundamentally improve the operation of the organization [96]. There are different kinds of DTs, all differing from one another on the levels of integration. The process of digital transformation is shown in Figure 3 below. Figure 2: Digital twin components with respect to the technical contributions of the 4 IR. Figure 3a above gives a general overview of digital transformation with specific focus towards digital twinning, while Figure 3b shows a comparative representation of a DT and a DT-predictive. * Digital Clone: This is an emerging technology involving deep learning (DL) algorithms that are used in manipulation of currently existing hyper-realistic media, i.e., audios, photos, and videos. With various establishments making digital cloning technology available to the public, functionalities such as audio-visual, memory, personality, as well as consumer behavior cloning can be realized [97]. A consumer behavior clone, a DT version of user behavior, can be a user profile or a cluster of customers based on their demographics. It must be noted, as can be seen in Figure 3a above, that innovation is realized when DTs and digital cloning are integrated. * Digital Thread: Since its aim is to signify the digitization and traceability of an asset throughout its lifespan, it can be defined as the foundation behind digital transformation [98]. This is made possible through linking all the DT capabilities, such as (i) its design, (ii) the performance data, (iii) the product data, (iv) the supply chain data, as well as (v) the software used in the creation of the product. Therefore, a digital thread, together with other DTs, can be used to meet certain design requirements, records, as well as all the data to be used. * Digital Replica: As shown in Figure 3b, a DT is referred to as a digital replica of a physical asset that has a two-way dynamic mapping between the physical asset and its DT. This is to say that the replica consists of a structure of connected elements and meta-information. * Digital Shadow: The definition of the digital shadow can be based on its purpose and existing relationship with the corresponding DT [99]. When the design objective is to serve a specific purpose, the digital shadow operates in isolation from the DT. In this way, the digital shadow provides a blueprint of the required data, its sources, the relationships between the various pieces of the data needed, as well as any data manipulations that need to be performed. The data are either forwarded directly from the digital shadow to the DT or the digital shadow performs some pre-processing and/or simulations itself. Therefore, based on the data that are delivered by the shadow, the DT integrates them into a complete digital reality for detailed processing, simulation, and analysis. * Digital Twin-Predictive: With reference to Figure 3b, the ultimate goal of a predictive twin is beyond the DT, as it aims to achieve further analysis for the purpose of predictions and individualization through the use of big data and ML in cyberspace. Therefore, a DT-predictive is a digital replica that uses two-dimensional real-time data communication over cyberspace. The above analyses show why a DT has several levels of integration, relating to the digital model and the digital shadow. These terms are most often used synonymously when in actual fact they are different in terms of data integration towards the physical, digital, and cyber layers [100]. With its current operational framework being the CIoT, which is  
Figure 3: (**a**) Process of digital transformation and (**b**) difference between a digital twin and a digital twin-predictive.