# Geo-Spatial Context Provision for Digital Twin Generation
## 3 A Digital Twin Architecture Linking CPS Behavior and Produced Operational Data
### Integrating the Introduced Concepts
Finally, the models need to be validated through the stakeholders holding the relevant knowledge. Like the modeling itself, this step can be supported by tools that allow for static checking and interactive enactment of the models to ensure syntactic and semantic correctness. Any of the activities associated with this step may be repeated to refine the models until they are deemed appropriate, given the outputs of the previous step. The final result of this step should be one SID and a set of SBDs for each chosen process. Ideally, the models should be in a format that allows for standardized data exchange (e.g., the semantic exchange standard proposed in [35]). However, existing modeling and run-time environments from the commercial sector often make use of their own formats. * Following model creation, the next step will be to set up a run-time environment for the subject-oriented process models and deploy them to it. If the previous steps already made use of such tools, then they can simply be re-used. A key requirement for the run-time environment is the ability to keep the running model instances synchronized with the state of the twinned process. This can be accomplished through a dedicated feature of the run-time environment itself, or through it offering the freedom of executing arbitrary code as part of a SBD state, allowing the implementation of features to request or receive status information of the twinned system to control instance execution (as sketched in Figure 9). * The next step concerns establishing the infrastructure for receiving and storing the required information from the twinned process and the physical behavior carriers. The data also needs to be provided to future consumers (visualization). Based on the identified goals of the DT, the explored use cases, and the gathered requirements, the data from the system that is needed is determined. Once the required data is known, a decision needs to be made with regard to how it should be stored. The gen eral format for the event log was outlined in the previous sub-section and an example is shown as part of Figure 9, but, e.g., the type of database(s) to be used should consider the expected types of data and their other characteristics (e.g.,: volume, velocity). Access to the database(s) can be encapsulated through various services built on top of it. * Next, the cyber-physical components that enact the modeled behavior need to provide the needed data to the storage infrastructure that was set up. This means that the components that need to provide data require some form of network connectivity. Furthermore, adaptions and extensions to their existing behavior will be necessary. Here, the impact that the additional communication would have on the performance of the components needs to be carefully considered. It might be likely that not all the data that was initially identified as potentially interesting for the twin can actually be provided without impacting the system in a significant manner. This is the reason, why these considerations were already mention at the beginning steps of the proposed methodology. Furthermore, the technologies used for realizing communication need to consider Quality-of-Service requirements that might exist. To summarize, one of the most important technical considerations during implementation relates to getting the relevant data from each component. * Once the infrastructure for getting the required data is in place, a user interface needs to be constructed that makes use of this data to provide various visualization features to DT users. Alongside event data, the created models can provide process context information, as shown in Figure 9.
* Before the system can be put into active operation, it needs to be evaluated with regard to the various requirements that were established. This step requires incorporating the DT's intended users and other involved stakeholders to ensure that it supports them as envisioned.