Monthly Archives: September 2014

Sea-Based Logistics Research Update

Pazour, ONR Fact Sheet September 2014PDF version: Pazour, ONR Fact Sheet September 2014

Above is an “at a glance” update on the research my team of students and myself are working on for the Office of Naval Research.

Seabasing is a United States Navy strategy that allows Joint Forces to be supported from the sea.  From a logistics perspective, seabasing will transform a set of vessels into floating distribution centers that are responsible for fulfilling supply orders from troops on shore.  Vital components of seabasing include selective offloading capabilities in high-space-utilization environments, ship-to-objective logistics via aerial delivery, and vessel-to-vessel cargo replenishment. In addition, sea-based logistics operate in a challenging and uncertain environment.  Thus, our research is interested in developing models to quantify and evaluate sea-based logistic system design in the face of imperfect visibility.  We focus on two important sea-based logistics decisions: selective offloading in dense storage environments and prestaging decisions in vessel-to-vessel cargo transfer.

Dense storage systems provide high-space utilization; however, because not all items are immediately accessible storage and retrieval operations often require shifting of other stored items in order to access the desired item. This shifting creates the propagation of uncertainty in item locations over time.    As a result of location uncertainty, before an item can be retrieved, the item needs to be identified, which requires searching.  We develop models that describe the propagation of uncertainty over time, as well as search plan optimization and expected search time models.

Underway Replenishment is a method for transferring cargo from one ship to another while the two ships are moving at sea.  To reduce the amount of idle time and improve the utilization of the transfer process, the concept of prestaging cargo on the flight deck is used. Prestaging involves retrieving and storing cargo on the flight deck of the supply ship in anticipation of requested demand.  The primary research question we are interested in is determining which items, and in what quantity, to prestage that balances the costs with the rewards of prestaging.  A secondary objective is to quantify the impact that uncertainty has on the logistics process of transferring cargo between ships.