IIC Journal of Innovation 16th Edition | Page 10

Web-Based Digital Twin
not suitable for use in the digital twin due to frequent incompatibility with simulations from other domains and , on the other hand , due to the required licenses and expertise . The problem of compatibility is addressed in corresponding standardization organizations [ 14 ] and scientific publications [ 15 , 16 ]. Vendor and domain independence can be achieved through open crossdomain modeling languages such as Modelica [ 17 ] and exchange formats like the Functional Mock-Up Interface ( FMI ). FMI is an open standard that defines a container and interface for exchanging dynamic models [ 18 ] and is particularly relevant in the presented context , since simulations can be supplied in the digital twin and integrated into a web-based environment . The goal is to provide a uniform interface to simplify the creation , storage , exchange , and reuse of simulations from different simulation environments . FMI can be divided into two process models : FMI for model exchange and FMI for co-simulation .
The dynamic models are packaged in a Functional Mock-Up Unit ( FMU ). An Extensible Markup Language ( XML ) file configures the FMU and C-code files describe the function . An FMU for model exchange only contains the model of the simulation . Accordingly , the tool for using an FMU must have its own solver for equation-solving . In an FMU for co-simulation , the model is compiled and exported with its own solver . This allows the tool to run the FMU independently with the solver provided and operate it without knowledge and ownership of solvers [ 18 ].
With the application of sensor data-based simulation models , the need for a dedicated Simulation Data Management for Digital Twins ( SDM-DT ) also arises . Derived from classical simulation data management systems from product development , the SDM-DT provides , manages and archives sensor-based simulation data [ 19 ]. Consequently , sensor-based simulation data can be managed in the digital twin to describe predictive and prescriptive scenarios . The performed simulations are virtually backed up and decision traceability is ensured [ 20 ].
Web Technologies
Both FMI and OPC UA already utilize web technologies such as various transfer protocols or offer corresponding interfaces . The multitude of protocols involved in the network connection between two end points can be divided into groups , which are represented , for example , in the OSI ( Open Systems Interconnection ) layer model [ 21 ]. Within individual groups , the protocols are interchangeable , resulting in many possible combinations . Widely used protocols include the Hypertext Transfer Protocol ( HTTP ), the Transmission Control Protocol ( TCP ) and the Internet Protocol ( IP ). Internet technologies are being further developed especially for industrial applications . Under the collective term Industrial Internet of Things ( IIoT ), the IIC offers concepts and architectures that make Internet technologies ready for industry and corresponds with activities within the Plattform Industrie 4.0 [ 22 ].
A variety of technologies exists not only for communication via the Internet , but also for the development of web resources . These can be classified into the three basic areas of frontend , backend and database . While the frontend is close to the user and is processed on his computer , the backend and database is executed on the server . For the development of web applications ,
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