# Toward a Practical Digital Twin Platform Tailored to the Requirements of Industrial Energy Systems
## 2 State of the Art
### Digital Twin Architectures
#### 2.5.3 Summary and Discussion  
In Table 4, a summary of the concepts, architectures and frameworks presented in the preceding paragraphs is given. The table was adapted and extended from our previous work [63]. It also gives a classification of the architectures based on their level of abstraction ranging from \"high\" (more general concept) to \"low\" (concrete framework, targeting implementation details).  
While abstract DT concepts are very useful for the initial development of the DT platform for a particular use case, they mostly do not indicate how to implement a DT. The propositions at a low level of abstraction that we found in our literature search either do not meet energy system specific requirements or lack the perspective of standardization.  
Aligning solutions with the architectural guidelines of the EDTA outlined above facilitates technology-independent implementations of DTs, thus ensuring reusability ultimately reducing development expenses. However, services are still considered in an abstract way in the EDTA, and appropriate implementation technologies have to be chosen. The prominent 5D-DT concept is being simple to understand in theory while keeping implementation details vague.  
We conclude that a more tangible DT platform, addressing the requirements for the domain of IES, can significantly facilitate DT implementation. Therefore, we propose a DT platform in Section 3 based on the previous work on the 5D-DT concept [80] and the EDTA [63]. The 5D-DT concept allows to conceptualize a specific DT based on five main dimensions, which are found in the majority of existing literature concepts. The EDTA, being also based on the 5D-DT concept, aims structuring its essential components and functionality and helps to classify, combine, and re-use already existing frameworks and technologies based on its alignment with RAMI 4.0.  
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Name** & **Target Domain** & **Structure** & **Main Parts** & **Level of Abstraction** \\ \hline
3D-DT [14] & Lifecycle management & component-based & 3 components & high \\
5D-DT [72] & Manufacturing & component-based & 5 components & high \\
5C Architecture [84] & CPSs in manufacturing & layer-based & 5 layers & high \\ Intelligent DT [85] & Production systems & component-based & 4 interfaces and 9 components & low \\ Ref. Framework for DT [21] & CPSs in general & component-based & 4 main components & low \\ “4S” architecture [31] & Battery management & layer-based & 4 layers & low \\ COCNITWIN [82] & Process industry & components and layers & 5 layers and 19 components & low \\ Conceptual DT model [92] & CPS in general & layer-based & 6 layers & medium \\ ASS [86, 87] & Manufacturing & only meta-model & ongoing work & - \\ The Twinning process [12] & DT characterization & only synchronization model & sequential processes & high \\ Data-driven reference architecture for DT [93] & Various industries & layer-based & 6 layers and several components & high \\ Digital Twin 8-dimension model [81] & Smart manufacturing & component based & 8 components & high \\ Application framework of DT [83] & Lifecycle management & modules and layers & 3 components and 1 layer & high \\ The Interactive Digital Twin [32] & Decision making in energy system design & only design model & sequential processes & low \\ GDTA [63] & Industrial Energy Systems & components, layers and services & 6 layers & medium \\ Robust DT for power plants [37] & Power plants & component-based & 5 components & medium \\ \hline \hline \end{tabular}
\end{table}
Table 4: Overview of concepts, architectures and frameworks for DTs. Adapted and extended from [PERSON] et al. [63].