A column generation approach for an inventory routing problem with fuzzy time windows

This paper proposes a novel approach towards inventory routing problems with fuzzy time windows considering customer satisfaction for arrival intervals. In the presented model, a multi-priority structure for visiting the customers is proposed. In this study, customers are divided into three categories according to their features. These features have different degrees of importance from the distributer’s perspective. The satisfaction level of customers plays an important role in the decision of the supplier to fulfill their demand in each period. Since the proposed model is characterized as a highly complex problem, a decomposition-based heuristic approach is developed to obtain a high-quality solution in reasonable computational time. Moreover, to properly calibrate the parameters of the developed algorithm and decrease the number of experiments, Taguchi experimental design technique is utilized to measure the efficiency of the parameter. Comparing the obtained results with previous studies indicates that the presented procedure outperforms similar heuristic-based solution techniques proposed in the relevant literature. Finally, the practical application of the proposed model is discussed by studying a real-world case study of a blood distribution system in Tehran.