Inventory models with forecast updates: Multiple delivery modes and service constraints.

摘要

Cost efficiency and customer satisfaction have always been two major objectives of inventory management. This study examines different aspects of inventory planning approaches under these objectives. We provide below a brief description of the results obtained for the specific problems considered in this study.; In the first problem discussed in chapter 2, we present a periodic-review inventory model with multiple delivery modes. While base-stock policies are optimal for one or two consecutive delivery modes, they are not so otherwise. For multiple consecutive delivery modes, we show that only the fastest two modes have optimal base stocks, and provide a simple counterexample to show that the remaining ones do not. We investigate why the base-stock policy is or is not optimal in different situations.; In the second problem, we consider a two-stage newsvendor model. The newsvendor orders an initial amount and has the possibility to adjust the initial order after he observes an updated demand signal. He also commits to a target service level before any forecast update is available. The resulting problem does not permit a dynamic programming formulation. We use the infinite-dimensional Kuhn-Tucker theory to solve the problem, and we derive analytical expressions for the optimal ordering decisions. In chapter 3, we study long-term type I service targets (probability of satisfying the demand). In chapter 4, we analyze long-term type II service targets (proportion of demand satisfied). We discuss how to evaluate these service measures and compare ordering policies under different planning approaches. Various properties of the optimal policy are discussed, and numerical results are presented to provide further managerial insights into the newsvendor's behavior.; In chapter 5, we extend the two-stage newsvendor problem by allowing for order cancellation at the second stage. Optimal ordering decisions are derived and are compared with those without the cancellation option. We further consider the supplier's production planning problem. A two-stage buy-back contract is proposed to coordinate the channel decisions. We also discuss how the channel profit is split between the vendor and the supplier.