Supply Chain Inventory Management Research
 

 

Value of Demand Observability for Inventory Control with Markovian Demand and Lost Sales
submitted, 2006.
(w/ O. Ortiz and C.C. White, III)

This paper considers a periodic-review, single-product inventory system serving serially-correlated customer demands, where demad is modeled using an exogenous Markov chain, such that the (discrete) demand distribution is dependent on the level of demand in the prior period. As in many real-world systems, unmet demand is lost and not directly observed; sales provide a screened observation of demand. The paper provides: (1) the development of a partially-observed Markov decision process (POMDP) model for determining optimal inventory replenishment policies for systems where demand is partially-observed via sales data; (2) the development of a parametric family of heuristic algorithms for determining near-optimal replenishment policies for large-scale problems; and (3) the development of an approach for bounding the maximum value of improving demand observability in such settings.
 

An Inventory Control Model with Possible Border Disruptions
submitted, 2005.
(w/ B.M. Lewis and C.C. White, III)

This paper develops a quantitative framework for analyzing the impact of single-bottleneck disruptions on simple one-to-one supply chains, focusing on the problem of determining optimal inventory control policies. Disruptions at the bottleneck lead to freight queues, which require multiple periods to dissipate. A methodology is developed to determine an appropriate distribution for the stochastic lead time induced by such systems, and then to determine optimal average cost inventory control policies and their costs.