Stochastic Port Selection Under Correlated Arc Disruptions: Improving Defence Supply Lines in the Nordics

Abstract

The expansion of NATO in the Nordic region is changing the requirements of the military distribution networks and may alter the optimal selection of seaports of debarkation (SPODs). This study offers a method for comparing and optimizing the selection of SPOD locations for inbound supplies and equipment, while accounting for regional attributes such as road network and weather conditions. To give strategic decision-makers insight into the trade-offs involved, we formulate a stochastic mixed integer linear program that models a multi-depot location-routing problem with arc disruptions within a broader military theatre distribution problem. Arc disruptions, referring to road closures, are drawn from historical data, and the model selects SPODs and allocates vehicles in advance, with daily vehicle routing depending on road conditions. By preserving the correlations observed in past road closures across time and space, the model shows that these correlations significantly influence optimal SPOD selection and resource allocation. Results also reveal that optimal SPOD selection changes depending on season and by the ratio of demand to distribution capacity. Hence, the methodology can support decision-makers in improving readiness and efficiency of military distribution operations in the Nordics.