Optimization of a Virtual Sustainable Closed-Loop Supply Chain Based on the Internet of Things and Blockchain under Uncertainty

In today’s competitive environment, the utilization of emerging technologies such as the Internet of Things and blockchain can lead to cost reduction, increased transparency, and service improvement in supply chains. In this regard, a multi-period, multi-product virtual closed-loop supply chain optimization model is developed, in which the Internet of Things and blockchain are employed to enable the timely recall of defective products and reduce disposal costs. The model is formulated as a four-echelon forward and three-echelon reverse mixed-integer linear mathematical programming and manages demand uncertainty through a fuzzy approach. The problem is solved for small- and medium-scale cases using GAMS, and for large-scale instances, due to its NP-hard nature, using the Grey Wolf Optimizer algorithm. To examine the importance of utilizing Internet of Things and blockchain technologies in the supply chain, two comparative studies are presented: the first study demonstrates the importance of the simultaneous implementation of these two technologies, and the second study focuses on the importance of blockchain. The results of the comparative studies indicate that the integration of the Internet of Things and blockchain enhances the sustainability, transparency, and profitability of the supply chain.