Modeling of Inventory Routing Problem with Intermediate Locations in Emergency Logistics Considering Uncertainty of Road Conditions

In recent years, natural disasters have occurred worldwide, causing tremendous damage. It is difficult to predict the scale of damage caused by natural disasters before they occur; and even after the scale of damage is understood, it is difficult to make accurate recovery plans and decisions based on limited information. Therefore, it is necessary to construct a system that supports decision-makers. Emergency logistics is a new field of logistics that plays an important role in disaster relief and recovery. The inventory routing problem (IRP) in emergency logistics has been attracting attention to reduce damage caused by disasters. Unlike usual logistics, emergency logistics considers two uncertainties: the uncertainty of the demand scale and the uncertainty of the distribution network, such as roads. Oshima et al. (2020) proposed an IRP model that focuses on inventory management in secondary storage warehouses where processing operations are possible, in addition to demand points, assuming the delivery plans for materials such as lumber are planned in a situation where available distribution networks are known or have been restored. On the other hand, no model has been proposed that considers damage to distribution networks, such as roads, in the recovery phase. In this study, we propose an IRP model that considers the uncertainty of the road network and utilizes existing facilities as processing bases. In addition, numerical experiments were used to verify the effects of using processing bases in emergency logistics for machinable building components.