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.     

Supply chain scheduling and coordination with dual delivery modes and inventory storage cost

We study a two-echelon supply chain scheduling problem in which a manufacturer acquires supplies from an upstream supplier and processes orders from the downstream retailers. The supply chain sells a single short-life product in a single season. We consider the scenario where the manufacturer can only accept some of the orders from the retailers due to its supplier's common production time window and its own two common production and delivery time windows. The upstream supplier processes materials and delivers the semi-finished products to the manufacturer within its time window. Then the manufacturer further processes these products to produce finished products and delivers them to the retailers within its two time windows, where one window is for production and normal delivery, and the other is for production and express delivery. Having to store the materials before processing them, the supplier incurs a storage cost, which depends on the order size and storage time. The manufacturer pays the transportation cost for delivering the finished products to the retailers. Due to double marginalization, the performance of the supply chain is sub-optimal. We model the supply chain problem as a flow shop scheduling problem with multiple common time windows. We derive some dominance properties and establish some theorems that help solve the sequencing problems for the orders and eliminate the idle time among the orders. Based on these results, we develop fast pseudo-polynomial dynamic algorithms to optimally solve the problem. We prove that the problem is NP-hard in the ordinary sense only. We develop two practically relevant and robust methods for the supply chain to achieve optimal profit-making performance through channel coordination.     

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.     

On supply chain coordination for false failure returns: A quantity discount contract approach

A large proportion of consumer returns fall into the category of false failure returns, which refer to returns without functional defects. In this paper, we consider profits resulting from exerting costly effort to reduce false failure returns in a reverse supply chain. The supply chain as a whole has a strong incentive to reduce such returns for cost saving. However, retailers typically enjoy a full credit provided by suppliers for returns, so they may not have sufficient incentives to exert enough effort for supply chain profit maximization. In some scenarios retailers may even have the motivation to encourage such returns. We suggest using a coordination contract to resolve this profit conflict. We introduce a quantity discount contract which specifies a payment to the retailer with an amount exponentially decreasing in the number of returns. We present explicit forms of such contracts given different assumptions about the distribution of the number of returns. We also prove that the contract is Pareto improving. Besides, it is shown that when the contract is applied in a closed-loop supply chain, it can deter retailer's potential incentive to encourage returns. Moreover, some modifications of the contract can lead to easy allocation of supply chain profit.     

Generalized single-vendor multi-buyer integrated inventory supply chain models with a better synchronization

Researchers have synchronized both the single-vendor single-buyer and the single-vendor multi-buyer integrated inventory supply chains by transferring the lot either only with equal-sized or only with unequal-sized sub-lot (batches). However, synchronization by transferring the lot with unequal and/or equal-sized batches (combination of unequal and equal sized batches along with the previous two cases), though available in the former case, the latter one lacks it. Accumulating the inventory in each of the vendor and the buyers, here we develop a generalized single-vendor multi-buyer supply chain model individually by extending the idea of such synchronization, and present logical development of their minimal cost solution techniques. Thereafter, we highlight theoretically the uniqueness of the present techniques by showing the best available methods as their special cases. Special cases are validated with the solutions of some numerical problems. Then their comparative studies with recently developed techniques on two numerical problems are carried out to show significant cost reductions.     

Optimization of a vendor managed inventory supply chain with guaranteed stability and robustness

In this work we address the steady state optimization of a supply chain model that belongs to the class of vendor managed inventory, automatic pipeline, inventory and order based production control systems (VMI-APIOBPCS). The supply chain is optimized with the so-called normal vector method, which has specifically been developed for the economic optimization of uncertain dynamical systems with constraints on dynamics. We demonstrate that the normal vector method provides robust optimal points of operation for a number of scenarios. Since the method strictly distinguishes economic optimality, which is treated as the optimization objective, from dynamical requirements, which are incorporate by appropriate constraints, it provides a measure for the cost of stability and robustness as a desired side-effect.     

Competitive pricing decisions in a two-echelon supply chain with horizontal and vertical competition

This study investigates the pricing decisions in a non-cooperative supply chain that consists of two retailers and one common supplier. The retailers order from the common supplier and compete in the same market. We analyze six power structures that characterize exclusively horizontal competition between the retailers and vertical competition between the supplier and the retailers, leading to different sequences of moves among the chain members. We derive the analytical forms of the equilibrium quantities under each power structure and explore the effect of retail substitutability on the equilibrium quantities among all power structures. We further investigate the performances of the game models as compared with the integrated model.     

A conceptual framework for evaluating the most cost-effective intervention along the supply chain to improve food safety

This paper develops a conceptual framework for choosing the most cost-effective intervention along the supply chain to improve food safety. This framework identifies both the initial level of on-farm infection and the potential for new infection post farm-gate as key parameters influencing the relative effectiveness of on-farm and abattoir interventions. In addition, the potential for cost economies of scale in implementing interventions at abattoir compared to on-farm is shown to be a further factor determining the relative cost-effectiveness of these interventions. Overall, it is suggested by the analysis in this paper that successful abattoir interventions will typically be more cost-effective than successful on-farm interventions. These findings are consistent with existing case study evidence.     

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.     

Internet-enabled coordination in the supply chain

The Internet fosters the integration of business processes across the supply chain by facilitating the information flows necessary for coordinating business activities. However, the Internet also supports the use of market mechanisms, such as auctions, that foster price competition. Using market mechanisms is less likely to generate a sustainable competitive advantage, but they might offer the opportunity to purchase some items at a lower price. Managers have the challenge of selecting the Internet-enabled coordination mechanism that best fits the needs of a variety of business situations in the supply chain. The authors present a framework to assist managers with this decision.     

An improved algorithm and solution on an integrated production-inventory model in a three-layer supply chain

Ben-Daya et al. (2010) established a joint economic lot-sizing problem (JELP) for a three-layer supply chain with one supplier, one manufacturer, and multiple retailers, and then proposed a heuristic algorithm to obtain the integral values of four discrete variables in the JELP. In this paper, we first complement some shortcomings in Ben-Daya et al. (2010), and then propose a simpler improved alternative algorithm to obtain the four integral decision variables. The proposed algorithm provides not only less CPU time but also less total cost to operate than the algorithm by Ben-Daya et al. (2010). Furthermore, our proposed algorithm can solve certain problems, which cannot be solved by theirs. Finally, the solution obtained by the proposed algorithm is indeed a global optimal solution in each of all instances tested.     

Modeling agility of supply chain

Agility is the fundamental characteristic of a supply chain needed for survival in turbulent and volatile markets, which are becoming norms as product life cycles shorten and environmental forces create additional uncertainty resulting in higher risk in the supply chain management. Agility further helps in providing the right product, at the right time to the consumer, which is the main objective of any supply chain. In the present paper, using interpretive structural modeling, interrelationships of the variables, influencing supply chain agility, have been derived. These variables have been categorized according to their driving power and dependence. This methodology provides a means by which order can be imposed on the complexity of such variables. The insight from model would help supply chain managers in strategic planning for improving supply chain agility.     

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.     

A centralized/decentralized design of a full return contract for a risk-free manufacturer and a risk-neutral retailer under partial information sharing

We consider the design of full return contract in a simple supply chain with a risk-free manufacturer and a risk-neutral retailer. In this problem, the ordering quantity and the rebate price for unsold products are determined by the retailer and the manufacturer, respectively. We propose an optimal solution procedure in centralized and decentralized decision making environments considering when the information sharing among the retailer and the manufacturer is partial. We provide numerical examples to explain the proposed solution procedures.     

Modeling defaults of companies in multi-stage supply chain networks

The interest in supply chain networks and their analysis as complex systems is rapidly growing. The physical approach to the topic draws on the concept of heterogenous interacting agents. The interaction among agents is considered as a repeated process of orders and production. The dynamics of production in the supply chain network which we observe is nonlinear due to the random failures in processes of orders and production. We introduce an agent-based model of a supply chain network which represents in more detail the real economic environment in which firms operate. We focus on the influence of local processes on the global economic behavior of the system and study how the proposed modifications change the general properties of the model. We observe collective bankruptcies of firms, which lead to self-emerging network structures. Our results give insight into the dynamics of default processes in supply chain networks, which have important implications both for risk managers and policy makers. Based on the simulations we show that agent-based modeling is a powerful tool for optimization of supply chain networks.     

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.     

Agility index in the supply chain

To achieve a competitive edge in the rapidly changing business environment, companies must align with suppliers and customers to streamline operations, as well as working together to achieve a level of agility beyond individual companies. Consequently, agile supply chains are the dominant competitive vehicles. Embracing agile supply chain requires asking some important questions, namely: what exactly is agility and how can it be measured? Moreover, how can agility be effectively achieved and enhanced? Due to the ambiguity of agility assessment, most measures are described subjectively using linguistic terms. Thus, this study develops a fuzzy agility index (FAI) based on agility providers using fuzzy logic. The FAI comprises attribute’ ratings and corresponding weights, and is aggregated by a fuzzy weighted average. To illustrate the efficacy of the method, this study also evaluates the supply chain agility of a Taiwanese company. This evaluation demonstrates that the method can provide analysts with more informative and reliable information for decision.     

Inventory control in a two-echelon dual-channel supply chain with setup of production and delivery

This paper considers a two-echelon dual-channel supply chain model with setup of production and delivery and develops a new inventory control policy for the supply chain. Previously, a two-echelon supply chain model without setup of production and delivery is considered and a one-for-one inventory control policy is applied to the supply chain. In the inventory control policy, production is stopped when the warehouse inventory reaches the upper limit and is started again immediately after the inventory drops below the limit. Moreover, delivery to the retailer is stopped when the store inventory reaches the upper limit and is started again immediately after the inventory drops below the limit. The total cost that consists of inventory holding costs and lost sales cost is considered, and setup costs are not considered in the total cost. Once setup costs are introduced, the one-for-one inventory control policy is no longer appropriate. Then, this paper develops a new control policy for the two-echelon dual-channel supply chain with setup of production and delivery. As performance measure, the total cost that consists of inventory holding costs, lost sales cost, and production and delivery setup costs is considered, and the total cost calculated on the basis of Markov analysis demonstrates the effectiveness of the proposed control policy.     

A vendor managed inventory supply chain with deteriorating raw materials and products

Fast deteriorating raw materials such as raw milk, fruit and vegetables are commonly used to produce slowly deteriorating finished products such as milk powders, cheeses, and pastas. This paper studies a Vendor Managed Inventory (VMI) type supply chain where the manufacturing vendor decides how to manage the system-wide inventories of its fast deteriorating raw material and its slowly deteriorating product. The decision variables are a common replenishment cycle of the product and the replenishment frequency of the raw material. We assume the deteriorating rates are known constants and every retailer's demand is deterministic. We develop an integrated model to calculate the total inventory and deterioration cost for such a system. We prove the convexity of the cost functions, and based on this a golden search algorithm is developed to find the optimal solution of the model. Our numerical results show that the deteriorating rate of the product may increase the total cost by more than 40% compared to the zero-deteriorating rate, while the deteriorating raw material has less impact on the total cost (commonly less than 5% in our numerical examples). This indicates that more attention should be paid to the product than the raw material. Further, an increase in the number of retailers can make the replenishment frequency of the raw material increase significantly but the common replenishment cycle of the product decreases a little. This indicates that adding a new retailer would not be felt strongly by the other retailers but would be felt by the supplier of the raw material.     

Linking product modularity and innovativeness to supply chain management in the Italian furniture industry

Much of the literature on modularity assumes that firms with modular products adopt modular organization. In the realm of supply chain management, no consensus has been reached on the effects of product modularity on supply chains (SC). This paper investigates whether SC choices depend on product modularity and innovativeness, and how SC choices can be aligned to these product features to maximize performance. A medium scale survey has been performed in the Italian furniture industry. By means of factor and cluster analyses, the SC of firms that introduced products with different levels of modularity and innovativeness have been compared. The results show that both product features must be considered when designing the SC.