Optimality and Nonoptimality of the Base-Stock Policy in Inventory Problems with Multiple Delivery Modes


Book Description

We present a periodic review inventory model with multiple delivery modes. We generalize the notion of the base-stock policy for inventory systems with multiple delivery modes. While base-stock policies are optimal for one or two consecutive delivery modes, it is not so otherwise. For multiple consecutive delivery modes, we show that only the fastest two modes have optimal base stocks, and provide simple counterexamples to show that the remaining ones do not in general. We investigate why the base-stock policy is not optimal through detailed analyses of two numerical examples.




Are Base-Stock Policies Optimal in Inventory Problems with Multiple Delivery Modes?


Book Description

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. This note is an abridged version of Q. Feng, S. P. Sethi, H. Yan and H. Zhang, Optimality and nonoptimality of the base-stock policy in inventory problems with multiple delivery modes, Journal of Industrial and Management Optimization, Vol. 2, No. 1, 2006, pp. 19-42.




Inventory and Supply Chain Management with Forecast Updates


Book Description

Real problems are formulated into tractable mathematical models, which allow for an analysis of various approaches. Attention is focused on solutions. Provides a unified treatment of the models discussed , presents a critique of the existing results, and points out potential research directions.




Periodic Review Inventory Systems


Book Description

The focus of the work is twofold. First, it provides an introduction into fundamental structural and behavioral aspects of periodic review inventory systems. Second, it includes a comprehensive study on analytical and optimization aspects of a specific class of those systems. For the latter purpose, general solution methods for problems of inventory management in discrete time are described and developed along with highly specialized methods to solve very specific problems related to the model variants examined. The work is thus addressed to students and practitioners who seek a deeper understanding of managing inventories in discrete time as well as to software developers who require implementation aids on specific problems of inventory management.




Dual Sourcing


Book Description

Companies with high-performing supply chains enjoy essential competitive ad- vantages. However, supply chain management faces an environment of rising risk that endangers these competitive advantages. One of the reasons is to outsource parts of their business. This bears the risk of significantly increased lead times and lead time variability. It is the impact of lead time variability on inventory management that is the central aspect of this book. It describes a mathematical model for dual sourcing with two reorder points, shows the deviation between stochastic and deterministic calculations in a sensitivity analysis, and investigates different relaxations of a traditional dual-sourcing policy.




Optimality of Base-Stock and (s, S) Policies for Inventory Problems with Information Delays


Book Description

Information delays exist when the most recent inventory information available to the inventory manager (IM) is dated; namely, the IM observes only the inventory level of an earlier period. We introduce information delays into the standard multiperiod stochastic inventory problem with backorders. We consider two types of information delays: (i) a constant delay and (ii) a random delay. We define an appropriate reference inventory position, which is a sufficient statistics for finding the optimal order quantity. We show that the optimal ordering policy is of base-stock type with respect to the reference inventory position and is of (s, S) type if there is also a fixed cost of ordering.




Innovative Quick Response Programs in Logistics and Supply Chain Management


Book Description

Quick Response (QR) policy is a market-driven business strategy in which supply chain members work together to react quickly to volatile market demand. Nowadays, with advances in information technologies (such as RFID and ERP systems), new challenges and opportunities arise for the application of QR. This handbook explores QR extensively with a view to discovering innovative QR measures that can help tackle the observed and emerging challenges. The book is organized into four parts, which include chapters on analytical modeling and analyses, information technologies, cases, reviews, and applications. This handbook provides new analytical and empirical results with valuable insights, which will not only help supply chain agents to better understand the latest applications of QR in business, but also help practitioners and researchers to know how to improve the effectiveness of QR using innovative methods.




Stochastic Processes, Optimization, and Control Theory: Applications in Financial Engineering, Queueing Networks, and Manufacturing Systems


Book Description

This edited volume contains 16 research articles. It presents recent and pressing issues in stochastic processes, control theory, differential games, optimization, and their applications in finance, manufacturing, queueing networks, and climate control. One of the salient features is that the book is highly multi-disciplinary. The book is dedicated to Professor Suresh Sethi on the occasion of his 60th birthday, in view of his distinguished career.




Optimal Policy in a Dynamic, Single Product, Nonstationary Inventory Model with Several Demand Classes


Book Description

A multiperiod single product nonstationary inventory problem is studied in which the system is reviewed at the beginning of each of a sequence of periods of equal length. The model has the following features. There are several classes of demand for the product in each period. The demands in different periods are independent but not necessarily identically distributed. The cost structure is nonstationary with the ordering cost being proportional to the amount ordered. Conditions are given that ensure that the base stock ordering policy is optimal and that the base stock levels in each period are easy to calculate. The results are based on earlier work of the author and on properties of stochastically ordered distributions that are developed in the paper. The case of a linear holding cost and a linear storage cost is studied in detail. (Author).




Some Cases of Optimality of the (s, S) Policy in Inventory Theory


Book Description

Loss functions are given for which there exist optimal two-level ordering policies (s,S) in one-stage inventory problems with an arbitrarily specified distribution of demand.