## 2 Architectural Design of IoT  
To initiate an IoT application, a certain data architecture design has to be predetermined. In the data architecture, a flow process that transforms raw data into useful data can be obviously seen. The architecture also enables us to understand what kind of software and hardware are necessary to build the IoT application. The following is a brief review of some proposed IoT architecture.  
A recent survey on the IoT in the industry mentioned that the International Telecommunication Union recommends that the IoT architecture should consist of five different layers, i.e., the sensing, accessing, networking, middleware, and application layers [6]. In addition, the authors in Reference [6] proposed a service-oriented architecture for industrial applications from the perspective of the functionalities of the four layers, namely, the sensing layer, the networking layer, the service layer, and the interface layer. In another review paper [7], the authors presented a three-layered architectural model for the IoT, which consisted of the application layer, the network layer, and the sensing layer. In one example in healthcare applications, the author proposed three major layers, i.e., the perception layer, the networking layer, and the service layer (or application layer) [3]. In a more relevant article to manufacturing processes that involved a lot of sensors, [PERSON] [8] proposed four layers comprising the physical layer, the transport layer, the middleware layer, and the application layer for sensory environments. According to the abovementioned reviews, a potential IIoT architecture for the manufacturing process is proposed as illustrated in Figure 2.  
In an industrial setting, the standard IoT architecture will serve as a rigid option and a more requirement-specific adaptation of the architecture becomes necessary. We consider the lowest layer as 'data', however, the data generated from the shop floor (as can be seen in Figure 1) will not exclusively be from physical sensors. The data will consist of sensor data, asset particulars, and images and information pertaining to the operator. Hence, generalising the lowest layer as a sensing layer is inadequate. The data acquired from various sources have to be classified with the metadata, while a preliminary assessment to derive the conclusions/predictions must be performed. A Human-Machine-Interface (HMI) and an application of the programming interface must be developed to fulfil this requirement. This can be classified under the 'application' layer. Another important consideration in such a scenario is safety. As the security of data generated within the industry and the shop floor is very crucial, adequate measures to ensure the safety of the data should be accounted for in the architecture itself. This brings us to the third proposed layer:'security'. In sequence, following data acquisition, process monitoring, and adequate encryption, the architecture can be packaged into a'service' in such a way as for the coherent information from the data to be easily understood by other personnel associated with supervisory and monitoring duties relating to the manufacturing process. This would improve productivity as any abnormal process behaviours can be predicted and, therefore, mitigated, hence, reducing equipment downtime [9].