Preface — Special Issue: Simulation in the AI Era — Advancing Complex Problem Solving

The increasing complexity and uncertainty in engineering, manufacturing, supply chain, and digital systems call for advanced simulation and artificial intelligence (AI) methodologies to support robust decision-making. This special issue presents 10 studies that demonstrate innovative approaches for addressing stochasticity, high-dimensional interdependencies, and dynamic environments. The featured works showcase advances in AI-enhanced simulation, data-driven optimization, multi-agent coordination, and risk-aware decision frameworks. Collectively, they emphasize computational efficiency and practical applicability, while pointing toward emerging research directions such as interpretable AI, scalable distributed systems, and real-time digital twins.