## 4 Linking the Two Approaches
### Graph-Based Design Languages Implemented with UML and DC43  
In the IFM Framework described in Section 3.1, functionality is represented using the entities process, operand, state, effect and actor. In the engineering framework described in Section 3.2, functionality is mainly represented with the entities object and process, and is additionally expressed with the associations between objects and attributes and the operations of objects. The most important entities of both approaches and their counterparts are shown in Table 2.  
It is important to note that this table reflects the state prior to the linking activities described subsequently. The entities described in the IFM Framework focus on the aim to represent all aspects of the functionality of the technical systems, whereas a prominent focus of the entities represented in the engineering framework based on UML, GBDL and DC43 is a representation that allows the compilation of geometrical models. In this framework, certain aspects of the product logic were also represented; these are related to the functionality of the technical system. For linking both approaches, entities were first identified that were the same or similar in both frameworks. The next scientific activities aimed to explicitly represent entities of the IFM Framework in the engineering framework, which were only implicitly expressed until then. For instance, the representation of the states of a technical system, which before was \"hidden\" in attributes, was realized as explicit classes in the UML class diagram and the associations were reworked accordingly. One example is that the states of the operand \"energy\" are part of the simulation of the overall trust when checking the functionality \"able to lift off\" (see [49]); still, these states and the operand are not explicitly represented in the class diagram. Finally, the entities, which were not represented originally, were newly created and integrated into the class \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt}} \hline \hline
**Entities in the IFM Framework** &
\begin{tabular}{c} **Entities in the Engineering Framework Based on** \\ **UML, GBDL and DC43** \\ \end{tabular} \\ \hline State (of operands) & Implicitly represented in attributes and operations \\ \hline Operand & Implicitly represented in attributes and operations \\ \hline Effect & Not yet represented \\ \hline States (of actors) & Implicitly represented in attributes and operations \\ \hline Actors (inheritance and hierarchy not expressed) & Object \\ \hline Process & Process \\ \hline Use case & UseCase \\ \hline Not yet expressed & Requirement \\ \hline System under consideration & TechnicalSystem \\ \hline Transformation and interaction processes & Not yet represented \\ \hline Stakeholders & Not yet represented \\ \hline Environment & Implicitly represented in attributes and operations \\ \hline Technical (Sub-)System & Module \\ \hline Not yet represented & Aggregation \\ \hline Not yet represented & Element \\ \hline Not yet represented & Imported classes (e.g., from geometry diagram) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Entities in both approaches and their counterparts (state prior to linking activities). diagram of the engineering framework and sensible associations were defined. To represent the linking of both concerned approaches, the initial class diagram illustrated in Figure 5 was remodeled in UML for enabling its use in the engineering framework based on UML, GBDLs and DC43. The respective class diagram is shown in Figure 12.  
In Figure 12, the entities, which were already represented and modeled in the IFM Framework, are integrated with the classes and instantiations represented and modeled in the engineering framework based on GBDLs. Following the proposed logic of the implementation endeavor, the next gaps/differences between the two approaches need to be addressed.