## 4 Requirement Validation and Compatibility Analysis
### Case-Based Requirement Analysis  
The DT process plays a significant role in the automotive industry, especially in the development of complex lighting systems. Validation of this process happens across several levels, each with a specific purpose. Initially, theoretical requirements are established through sketches, preliminary calculations, and risk analyses at the conceptual stage. This helps define general specifications and identify potential issues before starting development. Software algorithms are tested in a virtual environment, eliminating the need for physical components, verifying logic and performance, thereby reducing the requirement for early physical prototypes (SiL). Hardware components, such as ECUs or sensors, are tested by connecting them to a real-time simulator to validate system behavior under conditions close \begin{table}
\begin{tabular}{c c} \hline \hline
**Aspect** & **Details** \\ \hline Standard Overview & Leading architecture, global cooperation, separation of software and hardware, layered design \\ Digital Twin & Service-oriented architecture, modular design, \\ Integration & configuration, and automation \\ Testing and & Dependability assessment, automated testing tools, \\ Validation & model-based testing, virtual testing, and interface checks \\ \hline \hline \end{tabular}
\end{table} 
Table 2: AUTOSAR-compliant digital twin framework for automotive validation. to reality (HiL). Finally, a complete virtual replica of the system is created, which is used for complex simulations and predictive analyses (DT). This allows real-time monitoring, performance optimization, and problem detection before physical implementation. This process strengthens development and reduces associated risks. Table 3 summarizes different validation requirements (REQs). Requirement 1 is validated primarily at the SiL and DT stages, reflecting the focus on software logic testing and advanced virtual simulation. Requirement 2 is covered at all stages--conceptual, SiL, HiL, and DT--indicating it is a fundamental aspect addressed throughout the entire development process, from early theoretical definition to real-time monitoring. Requirement 3 appears only at the HiL and DT stages, highlighting the need for physical hardware testing and comprehensive virtual replication to validate system behavior under realistic conditions. Table 4, analyzing the conceptual, SiL, HiL, and DT perspectives on each requirement, highlights the progressive validation approach embedded in the development process. At the conceptual stage, the focus is on theoretical validation. Beam adjustment sketches or redundancy block diagrams are used to define functional expectations early on, enabling risk identification before any implementation begins. In the SiL phase, simulated environments and software models validate control logic under virtual conditions, such as testing response times or handling signal loss, without requiring physical hardware. This allows fast iterations and early detection of logic or integration issues. Moving into HiL, real components are integrated to test how the system responds to physical signals and disturbances, such as real camera inputs or fault injections. This stage brings virtual validation closer to reality by introducing tangible behaviors and interactions. Finally, the DT level provides a comprehensive, real-time simulation of the entire system within realistic scenarios--weather, traffic, and cascading faults--capturing complex interdependencies and verifying the system-wide impact. This layer closes the loop by enabling predictive analysis and performance optimization before physical deployment. It is important to note that Tables 3 and 4 present illustrative validation scenarios designed to demonstrate the structure and logic of the proposed framework. Although the data itself is fictional, the validation sequences and requirements reflect realistic engineering