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Articles 1 - 13 of 13
Full-Text Articles in Operations and Supply Chain Management
Trends In Manufacturing Inventory Efficiency: 1980-2013, Ahren Johnston
Trends In Manufacturing Inventory Efficiency: 1980-2013, Ahren Johnston
Atlantic Marketing Journal
This study was motivated by Cooke’s 2013 article questioning the inclusion on inventory carrying costs in CSCMP’s Annual State of Logistics Report since it is based on interest rates. This paper explores that question more fully and goes on to look at trends in inventory efficiency based on inventory turnover for U.S. manufacturing firms. Results of the study reveal that there has been a level trend between 1980 and 2013 after firm size is controlled for. Since these results are contradictory to those obtained by looking at inventory carrying costs as a percent of GDP, they suggest the need for …
Inventory Management Based On Target-Oriented Robust Optimization, Yun Fong Lim, Chen Wang
Inventory Management Based On Target-Oriented Robust Optimization, Yun Fong Lim, Chen Wang
Research Collection Lee Kong Chian School Of Business
We propose a target-oriented robust optimization approach to solve a multi-product, multi-period inventory management problem subject to ordering capacity constraints. We assume the demand for each product in each period is characterized by an uncertainty set, which depends only on a reference value and the bounds of the demand. Our goal is to find an ordering policy that maximizes the sizes of all the uncertainty sets such that all demand realizations from the sets will result in a total cost lower than a pre-specified cost target. We prove that a static decision rule is optimal for an approximate formulation of …
Optimizing (S, S) Policies For Multi-Period Inventory Models With Demand Distribution Uncertainty: Robust Dynamic Programming Approaches, Ruozhen Qiu, Minghe Sun, Yun Fong Lim
Optimizing (S, S) Policies For Multi-Period Inventory Models With Demand Distribution Uncertainty: Robust Dynamic Programming Approaches, Ruozhen Qiu, Minghe Sun, Yun Fong Lim
Research Collection Lee Kong Chian School Of Business
We consider a finite-horizon single-product periodic-review inventory managementproblem with demand distribution uncertainty. We formulate the problemas a dynamic program and prove the existence of an optimal (s, S) policy. Thecorresponding dynamic robust counterpart models are then developed for thebox and the ellipsoid uncertainty sets. These counterpart models are transformedinto tractable linear and second-order cone programs, respectively. Weillustrate the effectiveness and practicality of the proposed robust optimizationapproaches through a numerical study.
A Supply Chain Coordination Mechanism For Common Items Subject To Failure In The Electronics, Defense, And Medical Industries, Mikhail M. Sher, Seung-Lae Kim, Avijit Banerjee, Michael Paz
A Supply Chain Coordination Mechanism For Common Items Subject To Failure In The Electronics, Defense, And Medical Industries, Mikhail M. Sher, Seung-Lae Kim, Avijit Banerjee, Michael Paz
Michael Paz
Improved production processes, particularly miniaturization, have led to the development and use of non-reworkable items subject to failure in modern production environments. Coordinating supply chains for these items requires cooperation between suppliers and buyers in order to balance ordering/setup and holding costs among system partners. In this paper, we first determine optimal inventory policies for both the supplier and buyer. We then apply the bisection method to develop a mechanism which uses a common replenishment time to coordinate a supply chain consisting of a single supplier and n buyers. By utilizing this optimization framework, we minimize total system-wide costs and …
Electricity Trading And Negative Prices: Storage Vs. Disposal, Yangfang (Helen) Zhou, Alan Scheller-Wolf, Nicola Secomandi, Stephen Smith
Electricity Trading And Negative Prices: Storage Vs. Disposal, Yangfang (Helen) Zhou, Alan Scheller-Wolf, Nicola Secomandi, Stephen Smith
Research Collection Lee Kong Chian School Of Business
Electricity cannot yet be stored on a large scale, but technological advances leading to cheaper and more efficient industrial batteries make grid-level storage of electricity surpluses a natural choice. Because electricity prices can be negative, it is unclear how the presence of negative prices might affect the storage policy structure known to be optimal when prices are only non-negative, or even how important it is to consider negative prices when managing an industrial battery. For fast storage (a storage facility that can both be fully emptied and filled up in one decision period), we show analytically that negative prices can …
Humanitarian Logistics Network Design For An Effective Disaster Response, Soumia Ichoua
Humanitarian Logistics Network Design For An Effective Disaster Response, Soumia Ichoua
Soumia Ichoua
In this paper we address the problem of pre-positioning emergency supplies prior to a disaster onset. The goal is to ensure a fast and effective response when the disaster strikes. Pre-positioning of emergency supplies is a strategic decision aimed at determining the number and location of local distribution centers as well as their inventory levels for emergency supplies. These decisions must be made in a highly disruption-prone environment where a timely response is vital and resources are scarce. We present and discuss a scenario-based model that integrates location, inventory and routing decisions.
Stability And Endogenous Formation Of Inventory Transshipment Networks, Xin Fang, Soo-Haeng Cho
Stability And Endogenous Formation Of Inventory Transshipment Networks, Xin Fang, Soo-Haeng Cho
Research Collection Lee Kong Chian School Of Business
This paper studies a cooperative game of inventory transshipment among multiple firms. In this game, firms first make their inventory decisions independently and then decide collectively how to transship excess inventories to satisfy unmet demands. In modeling transshipment, we use networks of firms as the primitive, which offer a richer representation of relationships among firms by taking the coalitions used in all previous studies as special cases. For any given cooperative network, we construct a dual price allocation under which the network is stable for any residual demands and supplies in the sense that no firms find it more profitable …
Decision Support For Lead Time And Demand Variability Reduction, Xin Fang, Cheng Zhang, David J. Robb, Joseph D. Blackburn
Decision Support For Lead Time And Demand Variability Reduction, Xin Fang, Cheng Zhang, David J. Robb, Joseph D. Blackburn
Research Collection Lee Kong Chian School Of Business
Companies undertaking operations improvement in supply chains face many alternatives. This work seeks to assist practitioners to prioritize improvement actions by developing analytical expressions for the marginal values of three parameters – (i) lead time mean, (ii) lead time variance, and (iii) demand variance – which measure the marginal cost of an incremental change in a parameter. The relative effectiveness of reducing lead time mean versus lead time variance is captured by the ratio of the marginal value of lead time mean to that of lead time variance. We find that this ratio strongly depends on whether the lead time …
Robust Storage Assignment In Unit-Load Warehouses, Marcus Ang, Yun Fong Lim, Melvyn Sim
Robust Storage Assignment In Unit-Load Warehouses, Marcus Ang, Yun Fong Lim, Melvyn Sim
Research Collection Lee Kong Chian School Of Business
Assigning products to and retrieving them from proper storage locations are crucial in minimizing the operating cost of a unit-load warehouse. The problem becomes intractable when the warehouse faces variable supply and uncertain demand in a multi-period setting. We assume a factor-based demand model in which demand for each product in each period is affinely dependent on some uncertain factors. The distributions of these factors are only partially characterized. We introduce a robust optimization model that minimizes the worst-case expected total travel in the warehouse with distributional ambiguity of demand. Under a linear decision rule, we obtain a storage and …
Empirical And Analytical Essays On The Relationship Between Inventory And Transportation, Rodger David Swanson
Empirical And Analytical Essays On The Relationship Between Inventory And Transportation, Rodger David Swanson
Graduate Theses and Dissertations
This dissertation examines the relationship between inventory cost (IC) and transportation cost (TC). The association of the two has been recognized for over a hundred years; accordingly, managers and academics have believed that these costs have offsetting properties such that combinations of inventory and transportation expenditures can be altered to fit different strategic objectives. However, the behavior of this relationship in practice has not been tested. The essays of this dissertation examine this relationship through multiple theoretical lenses and with multiple data sets. Essay 1 examines aggregate IC and TC in the United States from 1960-2009. This period coincides with …
The Newsvendor's Optimal Incentive Contracts For Multiple Advertisers, Zhengping Wu, Pascale Crama, Wanshan Zhu
The Newsvendor's Optimal Incentive Contracts For Multiple Advertisers, Zhengping Wu, Pascale Crama, Wanshan Zhu
Research Collection Lee Kong Chian School Of Business
We consider a newsvendor who earns a revenue from the sales of her product to end users as well as from multiple advertisers paying to obtain access to those end users. We study the optimal decisions of a price-taking and a price-setting newsvendor when the advertisers have private information about their willingness to pay. We focus on the impact of the number of advertisers on the newsvendor’s optimal decisions. We find that regardless of the number of advertisers, the newsvendor may exclude advertisers with a low willingness to pay and distort the price and inventory from their system-efficient levels to …
Distribution Planning Considering Warehousing Decisions, Pratik J. Parikh, Xinhui Zhang, Bhanuteja Sainathuni
Distribution Planning Considering Warehousing Decisions, Pratik J. Parikh, Xinhui Zhang, Bhanuteja Sainathuni
11th IMHRC Proceedings (Milwaukee, Wisconsin. USA – 2010)
Modern supply chains heavily depend on warehouses for rapidly fulfilling customer demands through retail, web-based, and catalogue channels. The traditional approach that considers warehouses as cost-centers has affected the profitability of numerous supply chains. A lack of synchronization between procurement and allocation decisions causes warehouses to scramble for resources during peak times and be faced with under-utilized resources during drought times. Warehouses, however, have emerged as service-centers and it is imperative that warehousing decisions be an integral part of supply chain decisions. In this paper we propose a mixed-integer programming model to integrate warehousing decisions with those of inventory and …
The Empirical Determinants Of Inventory Levels In High-Volume Manufacturing, Marvin B. Lieberman, Susan Helper, Lieven Demeester
The Empirical Determinants Of Inventory Levels In High-Volume Manufacturing, Marvin B. Lieberman, Susan Helper, Lieven Demeester
Research Collection Lee Kong Chian School Of Business
This study uses survey data on several hundred automotive suppliers in North America to evaluate the determinants of inventory levels in high-volume discrete parts manufacturing. We assess the magnitude of raw materials, work-in-process, and finished goods inventories held at automotive supply plants. Inventories are shown to be jointly determined by technological and managerial factors in a manner roughly consistent with classical inventory theory. Several categories of managerial practices are found to be important. Low inventories are linked to employee problem solving and frequent communication with customers. More unexpectedly, we find the absence of inventory differences between U.S.-owned and Japanese-owned plants …