A Multi-Faceted Building-Block Method for Transparent and Extensible Discrete Process Modeling & Simulation

Process modeling and simulation (M&S) is a well-established paradigm for analyzing and designing complex systems. While commercial tools like SimEvents and AnyLogic offer powerful, component-based modeling capabilities, their underlying mechanisms are often opaque, limiting deep extension and customization for advanced research. In our work, we address this critical gap by proposing a formal, three-part building-block methodology for constructing discrete process M&S components. Our approach, grounded in and extending the DEVS (discrete event system specification) formalism, decomposes component design into three distinct yet interconnected facets: the internal hierarchical structure (X-Facet) of individual components; the nesting and composition relationships (Y-Facet) between components; and a novel, formalized inter-component collaboration protocol (Z-Facet) termed the Entity Flow-Control Flow-Processing Logic (ECPR) strategy. This methodology is engineered explicitly for transparency and extensibility, bridging the gap between the usability of commercial tools and the flexibility of open formalisms. We present its implementation within the open X-Language/XLAB framework, and validate it through three comprehensive case studies: a vehicle CAN bus/ABS system, a computational graph executor, and a custom component extension. Results demonstrate not only functional equivalence with commercial tools (Simulink, AnyLogic), but also, through a comparative architectural analysis and a usability pilot study, showcase superior extensibility and a manageable learning curve. This work provides a reference architecture for open, component-based simulation, enabling both intuitive graphical modeling and researcher-accessible simulation kernel extension.