## 6 Discussion  
In our case study, we applied structured features to integrate functional requirements and hardware system model elements into the CSA design. To achieve this, we utilized SFCAD, analyzing outputs such as the functional requirement list, hardware system model, structured feature list, traceability matrix, and CSA, which are all related to the functional requirement REQ_SW_01-01.  
The findings from our case study demonstrate that structured features can effectively bridge the gap between requirements analysis and design artifacts. The attributes of the structured features, which are derived from data and events involving both requirements and hardware system elements, directly influence the CSA design process through SFCAD. These attributes are reflected in key design stages, including component identification and interface operation allocation. Additionally, by positioning the SF.ID column between the ReqID and Component/Interface columns in the traceability matrix, the relationships between the two artifacts are clearly visualized, resulting in enhanced traceability.  
Figure 13: Association between artifacts in SFCAD.  
Despite the increasing complexity of the system, SFCAD applies a sensor-actuator pattern that addresses common challenges in the software design process. This pattern allows for a flexible and efficient embedded software design and can be extended to other software systems. Although the traceability process in SFCAD is manual, it provides a practical methodology for initiating design and integrating traceability into the development workflow.  
However, this study also has some limitations. First, the software architecture can vary depending on the designer's perspective, meaning that the designer's intent and viewpoint significantly impact the final design. SFCAD currently focuses only on the functional aspects related to data flow in CSA. While structured features include both data- and event-related attributes, SFCAD does not yet fully utilize event attributes. Incorporating event attributes to account for component execution timing could further enhance the tool's ability to model and track the dynamic characteristics of embedded software.  
Second, although SFCAD promotes requirement traceability in parallel with the design process, the manual creation and management of the traceability matrix imposes an additional burden on designers. This manual effort contributes to the tendency to conduct requirement traceability retrospectively or ignore it altogether, despite its critical importance. Automating or partially automating this process would require the development of tools that support design based on the mathematical models presented in Section 4.  
Third, although SFCAD primarily supports traceability between requirements and design during the component development process, requirements must be traceable throughout the entire software lifecycle, from analysis and design to implementation and maintenance. Currently, SFCAD specializes in the early stages of design traceability. Thus, extending its scope to support lifecycle-wide traceability, such as converting design outputs into code traceability, is necessary. Without establishing early traceability between the requirements and design, the burden on designers and developers may increase in later stages, making early traceability a critical challenge.  
Future research should address these limitations by exploring the applicability of structured features and SFCAD across diverse system environments, and should also analyze their impact on the overall development process. In addition, optimizing the application of structured features and developing automated tools represent ways of further enhancing traceability and efficiency.  
In conclusion, this study has demonstrated that structured features effectively narrow the gap between requirements analysis and design, leading a more efficient CSA design process in its early stages. These findings suggest that structured features can play an active role in future CSA designs.