## 2 Related Work
### DaaC Modeling Idea  
Space data is accompanied throughout the cycle of SIN, and it includes entity data and network data. No matter how the composition structure of the SIN changes, one of its components is invariance, and the space data resources will not be reduced. Meanwhile, with the collection, storage, and management of space data, the amount of space data resources will also gradually increase. In the current period, with the vigorous development of the theories and technologies of big data, data resources have gradually become a valuable asset in various fields. This is no exception for SIN. Therefore, this leads us to explore whether we can build the SIN architecture by making full use of those space data resources. At the beginning of the architecture framework design, scholars proposed a concept of \"product\" to meet the basic needs of system architecture design and modeling. Its essence and core is to make the reusable and interoperable data into a \"product\". The most common products include graphics, documents, etc. [24]. Since the proposal of the concept of the product, it has been considered the best choice for the description and modeling method of system architecture. In addition, earlier versions of the DoDAF (U.S. Department of Defense Architecture Framework)--version 1.0 and version 1.5--relied on \"products\" to run through the entire process of architecture description and modeling [25]. With the continuous use of \"products\", its shortcomings are increasingly prominent. The method has artificial subjectivity, and its portability and versatility is relatively poor. As a new concept, the SIN is gradually evolving from the concepts of the space information system (SIS), space equipment system (SES), etc. Therefore, this inspires us to consider whether we can refer to the architecture modeling method formed by its predecessor as the object and realize the architecture modeling of the SIN. For the predecessors of the SIN, some typical architecture modeling methods have been formed, and can be summed up into three categories: the modeling method based on the unified modeling language (UML), the activity-based architecture modeling method, and the \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Basis of Division** & **Feature Categories** \\ \hline
1 & Scale Structure & Complex Feature \\
2 & Networking Structure & Heterogeneous Feature \\
3 & Scope of Business & Heterogeneous Feature \\
4 & Resource Distribution & Restricted Feature \\
5 & Space Distribution & Hierarchical Feature \\
6 & Space-Time Behavior & Dynamic Feature \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Typical Feature Classification of SIN (Space Information Network). service-oriented architecture modeling method [17; 26; 27; 28]. Through comparative analysis, it can be seen that the UML-based method is an object-oriented analysis method, which is highly reusable and easy to upgrade and maintain. The activity-based approach takes the activity as the starting point; it is based on the core entity object of the architecture, and it has the advantages of flexibility and cross-product association. The service-oriented approach itself involves distributed software architecture that can describe the system architecture as a whole, thus improving the flexibility and adaptability of the architecture design. However, there are some shortcomings in the above methods, such as the poor interoperability and dependence on experience in the design process. Combined with the concept and features of the SIN, it can be seen that its nodes and links are dynamic and diverse. Correspondingly, the increase of network scale and the enhancement of network operation dynamics will increase the complexity of updating and planning the SIN architecture. Therefore, graphics, documents, and other \"products\" cannot be copied to accurately achieve effective the architecture description and modeling of the SIN.