[[alternative]]The Study of Supply Chain Inventory Model with Price-Sensitive Demand and Trade Credit

計畫編號：NSC96-2416-H032-007研究期間：200708~200807研究經費：460,000[[abstract]]在現今競爭性的市場環境，企業已經由獨立決策改變為協同合作來制定策略。為降 低成本及改善服務水準，有效的供應鏈策略必須考慮在供應鏈中不同層級之間的互動關 係。在複雜的供應鏈中，存貨的控制是相當困難的工作，而且對顧客的服務水準及整體 供應鏈系統的成本有顯著的影響。因此，在供應鏈管理（Supply Chain Management, SCM）模式下建立適當的整合存貨模型，如何決定同一供應鏈上合作夥伴的最適庫存/ 訂購策略，使得存貨相關總成本為最小或總利潤為最大，是本研究的主要內容。 本研究為二年期的研究計畫，將在考量商品的需求量隨價格變動(即需求率為銷售 價格的遞減函數)，且允許信用交易(供應商允許零售商延遲付款)下，分別建立適當的 整合存貨模型，以決定供應鏈中供應商與零售商的最適存貨策略。第一年在需求率固 定、且供應商允許零售商延遲付款的情況下，嘗試建立分別以供應商為領導者（零售商 為跟隨者）、零售商為領導者（供應商為跟隨者）及雙方合作的供應鏈存貨模型，並求 出Stackelberg 均衡解。。第二年在市場需求率為零售商銷售價格的遞減函數，且供應商 允許零售商延遲付款的情況下，考量非合作與合作賽局策略，建立並求解供應商與零售 商的最佳存貨決策模式。我們將嘗試利用數學證明最佳解存在的充分且必要條件，接著 建立一個演算法求出使得單位時間總利潤有最大值的最適解。最後，以數值範例說明求 解過程，並對重要的參數值進行敏感性分析。[[sponsorship]]行政院國家科學委員

Optimal economic order quantity for buyer–distributor–vendor supply chain with backlogging derived without derivatives

[[abstract]]In this article, we first complement an inappropriate mathematical error on the total cost in the previously published paper by Chung and Wee [2007, ‘Optimal the Economic Lot Size of a Three-stage Supply Chain With Backlogging Derived Without Derivatives’, European Journal of Operational Research, 183, 933–943] related to buyer–distributor–vendor three-stage supply chain with backlogging derived without derivatives. Then, an arithmetic–geometric inequality method is proposed not only to simplify the algebraic method of completing prefect squares, but also to complement their shortcomings. In addition, we provide a closed-form solution to integral number of deliveries for the distributor and the vendor without using complex derivatives. Furthermore, our method can solve many cases in which their method cannot, because they did not consider that a squared root of a negative number does not exist. Finally, we use some numerical examples to show that our proposed optimal solution is cheaper to operate than theirs.[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子

Modelling of Coordinating Production and Inventory Cycles in A Manufacturing Supply Chain Involving Reverse Logistics

In today’s global and competitive markets selling products at competitive prices, coordination of supply chain configuration, and environmental and ecological consciousness and responsibility become important issues for all companies around the world. The price of products is affected by costs, one of which is inventory cost. Inventory does not give any added value to products but must be kept in order to fulfill the customer demand in time. Therefore, this cost must be kept at the minimum level. In order to reduce the amount of inventory across a supply chain, coordination of decisions among all players in the chain is necessary. Coordination is needed not only for a two-level supply chain involving a manufacturer and its customers, but also for a complex supply chain of multiple tiers involving many players. With increasing attention being placed to environmental and ecological consciousness and responsibility, companies are keen to have a reverse supply chain where used products are collected and usable components remanufactured and reused in production to minimize negative impacts on the environment, adding further complexity to decision making across a supply chain. To deal with the above issues, this thesis proposes and develops the mathematical models and solution methods for coordinating the production inventory system in a complex manufacturing supply chain involving reverse logistics and multiple products. The supply chain consists of tier-2 suppliers for raw materials, tier-1 suppliers for parts, a manufacturer who manufactures and assembles parts into finished products, distributors, retailers and a third party who collects the used products and returns usable parts to the system. The models consider a limited contract period among all players, capacity constraints in transportation units and stochastic demand. The solution methods for solving the models are proposed based on decentralized, semi-centralized and centralized decision making processes. Numerical examples are used by adopting data from the literature to demonstrate, test, analyse and discuss the models. The results show that centralised decision making process is the best way to coordinate all players in the supply chain which minimise total cost of the supply chain as a whole. The results also show that the selection of the length of limited horizon/ contract period will be one of the main factors which will determine the type of coordination (decentralised, centralised or semi-centralised) among all players in the supply chain. We also found that the models developed can be viewed as generalised models for multi-level supply chain by examining the models using systems of different tiers from the literature. We conclude that the models are insensitive to changes of input parameters since percentage changes of the supply chain’s total cost are less than percentage changes of input parameters for the scenarios studied

Application of Optimization in Production, Logistics, Inventory, Supply Chain Management and Block Chain

The evolution of industrial development since the 18th century is now experiencing the fourth industrial revolution. The effect of the development has propagated into almost every sector of the industry. From inventory to the circular economy, the effectiveness of technology has been fruitful for industry. The recent trends in research, with new ideas and methodologies, are included in this book. Several new ideas and business strategies are developed in the area of the supply chain management, logistics, optimization, and forecasting for the improvement of the economy of the society and the environment. The proposed technologies and ideas are either novel or help modify several other new ideas. Different real life problems with different dimensions are discussed in the book so that readers may connect with the recent issues in society and industry. The collection of the articles provides a glimpse into the new research trends in technology, business, and the environment

Imperfect quality items in inventory and supply chain management

The assumption that all items are of good quality is technologically unattainable in most supply chain applications. Moreover, inventory theories are often built upon the assumption that the rates of demand, screening, deterioration and defectiveness are constant and known, even though this is rarely the case in practice. In addition, the classical formulation of a two-warehouse inventory model is often based on the Last-In-First-Out (LIFO) or First-In-First-Out (FIFO) dispatching policy. The LIFO policy relies upon inventory stored in a rented warehouse (RW), with an ample capacity, being consumed first, before depleting inventory of an owned warehouse (OW) that has a limited capacity. Consumption works the other way around for the FIFO policy. This PhD research aims to advance the current state of knowledge in the field of inventory mathematical modelling and management by means of providing theoretically valid and empirically viable generalised inventory frameworks to assist inventory managers towards the determination of optimum order/production quantities that minimise the total system cost. The aim is reflected on the following six objectives: 1) to explore the implications of the inspection process in inventory decision-making and link such process with the management of perishable inventories; 2) to derive a general, step-by-step solution procedure for continuous intra-cycle periodic review applications; 3) to demonstrate how the terms “deterioration”, “perishability” and “obsolescence” may collectively apply to an item; 4) to develop a new dispatching policy that is associated with simultaneous consumption fractions from an owned warehouse (OW) and a rented warehouse (RW). The policy developed is entitled “Allocation-In-Fraction-Out (AIFO)”; 5) to relax the inherent determinism related to the maximum fulfilment of the capacity of OW to maximising net revenue; and 6) to assess the impact of learning on the operational and financial performance of an inventory system with a two-level storage. Four general Economic Order Quantity (EOQ) models for items with imperfect quality are presented. The first model underlies an inventory system with a singlelevel storage (OW) and the other three models relate to an inventory system with a two-level storage (OW and RW). The three models with a two-level storage underlie, respectively, the LIFO, FIFO and AIFO dispatching policies. Unlike LIFO and FIFO, AIFO implies simultaneous consumption fractions associated with RW and OW. That said, the goods at both warehouses are depleted by the end of the same cycle. This necessitates the introduction of a key performance indicator to trade-off the costs associated with AIFO, LIFO and FIFO. Each lot that is delivered to the sorting facility undergoes a 100 per cent screening and the percentage of defective items per lot reduces according to a learning curve. The mathematical formulation reflects a diverse range of time-varying forms. The behaviour of time-varying demand, screening and deterioration rates, defectiveness, and value of information (VOI) are tested. Special cases that demonstrate application of the theoretical models in different settings lead to the generation of interesting managerial insights. For perishable products, we demonstrate that LIFO and FIFO may not be the right dispatching policies. Further, relaxing the inherent determinism of the maximum capacity associated with OW, not only produces better results and implies comprehensive learning,but may also suggest outsourcing the inventory holding through vendor managed inventory

Supply chain coordination and integration under yield loss

The primary objective of this dissertation is to develop analytical models for typical supply chain situations to help supply chain decision-makers under supply yield loss. We derive solution procedures for each model and present several managerial insights obtained from our models through numerical examples. Additionally, this research provides decision-makers insights on how to incorporate uncertainty in demand and supply and shortage information into a mathematical model. This study deals with three forms of integrated cost-profit models under different scenarios including coordination policy and supply yield loss in a two-stage supply chain involving a retailer and a supplier, dealing with a single product under deterministic condition. We compare the profits of the whole supply chain system under the coordinated policy with those of individual decision making approaches and demonstrate the efficiency of coordination. These models attempts to find the optimal solutions for the retailer’s order quantity, quality level, amount of emergency procurement, and the production and shipment decisions of the supplier, so that the resulting joint total profit for the entire supply chain is maximized. We illustrate our model and the potential benefits of outsourcing in a supply chain system through a numerical example. Extending the analyses obtained above, we then develop models for an integrated supplier–retailer supply chain under imperfect production and shortages, with the additional decision variable of market pricing on the part of the retailer. We assume that market demand is sensitive to the retailer’s selling price and study the combined operation and pricing decisions in the supply chain. We develop profit maximization models for the cases of independent and joint optimization. The results of obtained from our analyses demonstrate that the individual profit, as well as joint profit can be increased by our suggested model, under a non-linear price dependent demand function. In addition, the results with retailer-supplier coordination tend to be superior, which leads to illustrate that setting appropriately retailer’s selling price can increase market demand and the profits of both parties, as well as that of the supply chain. Finally, numerical examples are presented to illustrate these models, and the sensitivity analyses of a selected set of model parameters on the total profit is conducted. A major finding of this study is that coordination between the retailer and the supplier improves channel profit significantly. Furthermore, the possibility of external procurement tends to improve total system profitability as the price sensitivity of demand increases.Ph.D., Business Administration -- Drexel University, 201

Supply Chain

Traditionally supply chain management has meant factories, assembly lines, warehouses, transportation vehicles, and time sheets. Modern supply chain management is a highly complex, multidimensional problem set with virtually endless number of variables for optimization. An Internet enabled supply chain may have just-in-time delivery, precise inventory visibility, and up-to-the-minute distribution-tracking capabilities. Technology advances have enabled supply chains to become strategic weapons that can help avoid disasters, lower costs, and make money. From internal enterprise processes to external business transactions with suppliers, transporters, channels and end-users marks the wide range of challenges researchers have to handle. The aim of this book is at revealing and illustrating this diversity in terms of scientific and theoretical fundamentals, prevailing concepts as well as current practical applications