Non-cooperative strategies for production and shipment lot sizing in one vendor-multi-buyer system

The supply chain structure examined in this paper consists of a single vendor (or manufacturer) with multiple heterogeneous buyers (or retailers). A continuous deterministic model is presented. To satisfy buyers demands, the vendor will deliver the product in JIT shipments to each buyer. The production rate is constant and sufficient to meet the buyers’ demands. The product is shipped in discrete batches from the vendor's stock to buyers’ stocks and all shipments are realized instantaneously. Special production-replenishment policies of the vendor and the buyers are analyzed. That is, the production batch is transferred to each buyer in several sub-batches in each production distribution cycle (PDC).This paper offers game model without prices, where agents minimize individual costs. It is a non-cooperative (1+N)-person game model with agents (a single vendor and N-buyers) choosing numbers and sizes of transferred batches. The model describes inventory patterns and cost structure of PDC. It is proved that there exist Nash equilibria in several types of sub-games of the considered game.     

Structuring and contracting in competing supply chains

This paper considers two competing supply chains, each with multiple upstream suppliers producing complementary products and selling to a single buyer (e.g., assembler or retailer), who then sells the finished assembled product to a market that involves both demand uncertainty and competition. Our main research questions focus on what supply chain structure (integration vs. decentralization) and which contracting strategy a business should choose. We find that supply chains that decentralize perform better under strong market competition (i.e., high degree of product substitution between supply chains). However, when a large number of suppliers exist, supply chains that integrate perform better. When decentralized structures are used for both supply chains, a consignment with revenue sharing contract generally outperforms a wholesale price contract from the downstream retailer's point of view. Interestingly, for a supplier, a wholesale price contract, which pushes all demand risks to the downstream retailer, might not be preferred. For the entire supply chain, one contract strategy can outperform another depending on the degree of competition, the cost share of the buyer, and the number of suppliers.     

An integrated production-distribution model for a deteriorating inventory item

We develop an integrated production-distribution model for a deteriorating item in a two-echelon supply chain. The supplier’s production batch size is restricted to an integer multiple of the discrete delivery lot quantity to the buyer. Exact cost functions for the supplier, the buyer and the entire supply chain are developed. These lead to the determination of individual optimal policies, as well as the optimal policy for the overall, integrated supply chain. We outline a procedure for determining the optimal supply chain decisions with the objective of minimizing the total system cost. Our approach is illustrated through a numerical example.     

Short-term financing in a cash-constrained supply chain

In this paper we consider a two-level supply chain with a single retailer and a manufacturer, where both the firms are facing financial constraints and can not produce/order their optimal quantity. Our work shows that a lender who finances the manufacturer has a motivation to finance the retailer as well. Motivated by this, we investigate lender's problem of financing both the firms by making a joint decision on the loan amount and comparing it with the case when lender makes independent decision on loan amount for both the firms. Our numerical study indicates that if one of the firms in the supply chain has sufficiently low cash, joint decision (we refer to it as supply chain financing) may be better not only for the lender but for the retailer and manufacturer as well.     

A co-ordination model combining incentive scheme and co-ordination policy for a single-vendor-multi-buyer supply chain

Incentive scheme and co-ordination policy are substantial components for the co-ordination of a decentralized supply chain system, but there is little work combining the two components as a single decision model (Li and Wang, 2007). This paper proposes a model which incorporates both incentive and co-ordination issues into a single co-ordination model for a single-vendor multi-buyer supply chain. In the proposed model, the co-ordination is achieved by synchronizing ordering and production cycles while price discount, which is based on the buyers’ order intervals, is used as the incentive to motivate buyers to participate in the co-ordination. While the vendor is benefited from the co-ordination by synchronized cycles, the proposed price discount scheme can guarantee that a buyer’s total relevant cost of co-ordination will be reduced when compared with independent optimization. More importantly, the proposed price discount scheme does not require any cost information from the buyers.     

Lead time reduction through ICT application in the footwear industry: A case study

This paper analyses some relevant supply chain management issues for Italian firms operating in the footwear industry. The analysis is carried out on representative firms, located in a specialized regional district with a high density of shoe manufacturing companies. Companies were experiencing substantial problems in the management of supplier relationships, as well as in the commercial/distributive channel. Specifically, synchronization issues in the logistics pipeline were weakening firms’ lead time performances.The case study presented strives to highlight the critical points in the set up of the supply chain management programme, as well as the main results obtained. The case study also shows that the adoption of tailored Information and Communication Technology (ICT) tools has the potential to save significant lead time in supplier/buyer relationships. From the case study, generalities can be drawn and transferred to the footwear industry.     

A JIT lot-splitting model for supply chain management: Enhancing buyer–supplier linkage

This study develops a buyer–supplier coordination model to facilitate frequent deliveries in small lot sizes in a manufacturing supply chain. The proposed model, based on the integrated total relevant costs of both buyer and supplier, determines optimal order quantity, the number of deliveries/setups, and shipping quantity over a finite planning horizon in a relatively simple JIT single buyer single supplier scenario. Under deterministic conditions for a single product, we show that the optimal delivery policy adopted by both buyer and supplier in a cooperative manner can be economically beneficial to both parties. It is shown that the optimal delivery size can be unique, regardless of the order quantity and the number of deliveries. Numerical results are also presented.     

How accurate is the integrated vendor–buyer continuous model?

The classic single-item, deterministic-demand, integrated vendor–buyer model is revisited. The decision problem may also be viewed as that of one centralized firm, dealing with a two-level EOQ-like supply chain with finite production rates. It is sought to optimize the production lot-size and the integral number of its shipments, in equal batches, from the vendor to the buyer. While the problem calls for discrete optimization techniques, we introduced a continuous model where one can take derivatives with respect to both variables. In this short paper, we establish a 98.5% lower bound on the accuracy of this continuous model.     

Applying activity-based costing in a supply chain environment

Traditional intra-firm cost accounting tools are not appropriate in the context of supply chain management, as there are no standards for the definition and composition of costs. This prohibits exchange and comparison of cost data among different supply chain members. Against this background, several activity-based costing models for inter-firm cost accounting have been proposed. Evaluating these models, a conceptual framework for activity-based costing in a supply chain has been developed. This also forms the basis for a single case study conducted at Europe's largest company for façade components. This demonstrates how significant inter-firm cost saving opportunities can be identified and offers a first step in assessing the suitability of the proposed model.     

Supply chain management in the luxury industry: A first classification of companies and their strategies

This paper aims at analysing the supply management strategies in the luxury industry in order to find out (1) whether different clusters of companies could be identified within the luxury industry, on the base of a set of contingent variables derived from previous research, and (2) which supply chain strategy is currently applied within each cluster. Case study methodology is used. A sample of 15 Italian luxury companies, belonging to different industrial sectors, was taken into account.On the basis of five classification variables (company size, selling volume, product complexity, product fashionableness and brand reputation) four clusters are identified; these clusters present differences in terms of Supply Chain strategy, as well as in terms of practices for managing manufacturing, sourcing and distribution processes.     

Inventory control in a two-level supply chain with risk pooling effect

We consider an inventory control problem in a supply chain consisting of a single supplier, with a central distribution center (CDC) and multiple regional warehouses, and multiple retailers. We focus on the problem of selecting warehouses to be used among a set of candidate warehouses, assigning each retailer to one of the selected warehouses and determining replenishment plans for the warehouses and the retailers. For the problem with the objective of minimizing the sum of warehouse operation costs, inventory holding costs at the warehouses and the retailers, and transportation costs from the CDC to warehouses as well as from warehouses to retailers, we present a non-linear mixed integer programming model and develop a heuristic algorithm based on Lagrangian relaxation and subgradient optimization methods. A series of computational experiments on randomly generated test problems shows that the heuristic algorithm gives relatively good solutions in a reasonable computation time.     

ORDER PROCESSING COST REDUCTION IN A JOINT VENDOR-BUYER INVENTORY SYSTEM VIA THE APPLICATION OF INFORMATION TECHNOLOGY

Modem information technologies have become important means for manufacturing and retailing firms to gain such competitive advantages as lower logistics costs and securer customers' loyalty. In this paper, we investigate a joint inventory system where the vendor produces a single item for its sole buyer and the buyer sells the item to consumers with backorders allowed. Each production lot is delivered to the buyer in a number of shipments and consecutive shipments will be increased by a fixed factor. Both vendor and buyer are willing to participate in order processing time reduction by applying information technologies in order to decrease their joint total cost. The order processing time can be reduced by certain expenditures and will affect the lot-size decisions. An analytical model is developed for determining the optimal expenditure in order processing time reduction and lot sizes for both vendor and buyer. The numerical experiment along with sensitivity analysis is also performed to obtain some insights of our model.     

Agents’ incentives under buy-back contracts in a two-stage supply chain

This paper investigates how the behavior of individual decision makers can affect the performance of a supply chain. We study a two-stage supplier–retailer system, using a buy-back contract. Each firm's actions are executed by an agent. The retailer's purchasing agent and the supplier's sales agent are compensated based on certain performance measures, and they act accordingly. We study the impacts of their behavior in both the supplier-as-leader and retailer-as-leader settings. We find that, unless their incentives are carefully constructed, the agents can strongly distort the system's behavior. Specifically, “channel stuffing” (packing the distribution channel with excess inventory) can occur in both settings. Only when the agents are compensated based on net profit do they act in accord with their firms’ objectives. These results may help explain some recent scandals.     

本土装备制造业市场空间障碍分析——基于下游行业全球价值链的视角

本文在全球价值链框架下,研究我国本土装备制造业市场空间障碍的产生机制以及实现有效产业升级的政策取向问题。本文发现,作为购买者驱动型全球价值链的主导者,国际大买家将从实现自身最优利润出发,设定从发展中国家消费品厂商采购的最优产品质量要求。为了获得质量更好的消费品,国际大买家愿意提高采购价格。国际大买家的纵向压价行为,与选择以发达国家为主要目标市场的策略,均有利于其方便设定最优产品质量要求。发展中国家消费品厂商被国际大买家俘获后,倾向于选择进口机器设备,这使本土装备制造业面临必然的市场空间障碍。构建国家价值链,提高价值链终端的竞争程度,有助于突破本土装备制造业的市场空间障碍。     

Conceptual modelling for supply chain inventory visibility

Visibility becomes increasingly important for companies that seek to globalise their supply chains due to the increasing complexity involved. This paper contributes to the research on Supply Chain Visibility (SCV) from an inventory perspective with a focus on inventory visibility, which is a critical part of SCV. The characteristics of Inventory Visibility (IV), which are inherited from SCV, are conceptually analysed. A theoretical model in terms of atom, single, and compound visibility, is developed based on the characteristics identified. A method for objectively measuring IV is presented together with a case example to demonstrate its convenience and usefulness.     

Setting operating policies for supply hubs

This paper deals with the joint management of operations at the supply hub for the customer and the upstream supplier. Different operating conditions are considered, namely, backordering, minimum and maximum specified inventory levels. Some analytical insights on better managing suppliers operating under a vendor managed inventory program are presented. Essentially, we show that the penalty cost imposed on over- and under-stocking, and the min–max policy for hub inventory reside in the power of the hub operator. The relationship between supply hub policy and performance measures is quite complex and non-linear in nature. We suggest a structured hierarchical approach which can help supply hub in achieving balance between various parties involved in chain. A numerical example and an algorithm are included to highlight this result.     

Development of a process mining system for supporting knowledge discovery in a supply chain network

In today's competitive environment, business organizations are forced to maintain their competitive advantage by their ability to cut costs, increase revenue and uncover hidden issues. In order to enhance the visibility and transparency of value added information in a supply chain network, a process mining system is proposed for discovering a set of fuzzy association rules based on the daily captured logistics operation data, within the network. The proposed methodology provides all levels of employees with the ability to enhance their knowledge and understanding of the current business environment. Once interesting association rules have been extracted, organizations can identify the root-causes of quality problems in a supply chain and improve performance by fine-tuning the configuration of process parameters in specified processes. The application of the proposed methodology in a case company has also been studied. The prototype system has been developed and evaluated after performing a spatial analysis. The results obtained indicate that the system is capable of extracting high-quality and actionable information in the case company.     

The analysis of bullwhip effect in a HMMS-type supply chain

The aim of the paper is to investigate the well-known bullwhip effect of supply chains. Control theoretic analysis of bullwhip effect is extensively analyzed in the literature with the Laplace transform. This paper tries to examine the effect for an extended Holt-Modigliani-Muth-Simon model. A two-stage supply chain (supplier-manufacturer) is studied with quadratic costs functional. It is assumed that both firms minimize the relevant costs. The order of the manufacturer is delayed with a known constant. Two cases are examined: supplier and manufacturer minimize the relevant costs decentralized, and a centralized decision rule. The question is answered, how to decrease the bullwhip effect.