Аңдатпа
This paper analyzes the joint coordination of green investment and inventory decisions in a two-echelon supply chain operating under demand uncertainty. The supply chain consists of a manufacturer with imperfect production and a retailer exposed to stockout risk. The manufacturer invests in Industry 4.0 technologies to enhance product greenness, which drives market demand and generates cost spillovers for the retailer. Using an EOQ-based framework, we analyze centralized and decentralized decision-making under deterministic demand and then extend the model to a stochastic setting by incorporating probabilistic lead-time demand. The results show that decentralized decision-making leads to systematic underinvestment in green technologies and lower supply chain profitability compared to the centralized benchmark. These inefficiencies are amplified under demand uncertainty. To address this coordination failure, the paper proposes a cost-sharing contract that align incentives across supply chain members. Numerical analysis shows that the proposed contract increases green investment and improves service performance. Under varying backorder rates, total supply chain profit increases by an average of 10.72%, achieving Pareto efficiency. This study contributes to the EOQ and stochastic inventory literature by integrating green investment decisions, imperfect production, and digital spillover effects into a unified coordination framework, offering actionable insights for sustainable supply chain management in the context of Industry 4.0.