Efficient location of industrial activity cells in a global supply chain

Inefficient locations for production, distribution and reverse logistics plants will result in excess costs no matter how well material requirements planning (MRP), inventory control, distribution and information sharing decisions are optimized. In this paper we study ways in which aspect of activity cell location decisions can be analyzed within an extended MRP model. This model has previously been extended by including distribution and reverse logistics components in a compact form, presented in Grubbström et al. (2007). Our aim is to demonstrate the basic differences between an approach to location problems with MRP “under the same roof” as the global supply chain, in which transportation time delays and direct transportation costs have substantial influence. We discuss possibilities of how to present location aspects in the supply chain model obtained from combining input–output analysis and Laplace transforms in four sub-systems, namely manufacturing, distribution, consumption and reverse logistics, and show how the transportation costs and lead time influenced by the location of all these activities affect the resulting net present value (NPV). Our aim is to build a model supporting decisions concerning the structure of a supply chain as an alternative to a mixed integer programming formulation. The model developed is based on the use of continuous functions describing spatial distributions of cost and customer demand. Continuous functions are embedded in the MRP extension previously introduced in Grubbström et al. (2007).Location decisions influence (i) production costs, because timing influences the cost of activities involved in creating a product, cf. (Grubbström and Bogataj, submitted for publication), and (ii) logistics costs, which refer to the procurement and physical transmission of materials through the supply chain. In this current paper we wish to combine both of these aspects into a comprehensive model, where we show the interaction between the “space of flows” and the “space of places” as Giovanni Arrighi distinguishes one from the other in his book The Long Twentieth Century.     

A weighted max-min model for fuzzy multi-objective supplier selection in a supply chain

Supplier selection is one of the most important activities of purchasing departments. This importance is increased even more by new strategies in a supply chain. Supplier selection is a multi-criteria decision making problem in which criteria have different relative importance. In practice, for supplier selection problems, many input information are not known precisely. The fuzzy set theories can be employed due to the presence of vagueness and imprecision of information. A weighted max-min fuzzy model is developed to handle effectively the vagueness of input data and different weights of criteria in this problem. Due to this model, the achievement level of objective functions matches the relative importance of the objective functions. In this paper, an analytic hierarchy process (AHP) is used to determine the weights of criteria. The proposed model can help the decision maker (DM) to find out the appropriate order to each supplier, and allows the purchasing manager(s) to manage supply chain performance on cost, quality and service. The model is explained by an illustrative example.     

Dynamic supply chain modeling using a new fuzzy hybrid negotiation mechanism

The key part of dynamic supply chain management is negotiating with suppliers and with buyers. Coordination is essential for successful supply chain management. In order to model coordination among suppliers and buyers in a dynamic supply chain, this paper takes a step further and proposes a new fuzzy- logic-based hybrid negotiation mechanism. In most real-world negotiation situations, agents have a common interest to cooperate, but have conflicting interests over exactly how to cooperate. These situations involve restrictions and preferences that may be vaguely and partly defined. Therefore, this study takes the advantage of fuzzy logic and develops a hybrid negotiation-based mechanism, that combines both cooperative and competitive negotiations. Achieving effective coordination in a multi-agent system is non-trivial as no agent possesses the global view of the problem space. Moreover, the different strategies adopted by agents may produce conflicts. While agents coordinate with each other in the operations, they will negotiate about their strategies to reduce conflicts. The proposed fuzzy hybrid negotiation mechanism allows negotiation agents more flexibility and robustness in an automated negotiation system. The proposed mechanism not only helps sellers and buyers to explore various new choices and opportunities that the e-markets offer but also allows them to identify and analyze their resource constraints in a given schedule, and helps them to explore and exploit many alternatives for a better solution. The efficacy of the proposed approach is demonstrated through an illustrative example.     

Managing channel coordination in a multi-channel manufacturer-retailer supply chain

With the rapid development of e-commerce and the adoption of dual channels, increasingly manufacturers and retailers are implementing differentiated branding and profit sharing strategies in order to improve channel coordination and supply chain performance. In this study, we focus on the strategic roles played by differentiated branding and profit sharing in a multi-channel manufacturer-retailer supply chain. We use an analytical model to investigate this issue. Our results show that although differentiated branding effectively alleviates channel competition and conflict, it is general not sufficient to achieve full channel coordination, and an additional coordination mechanism is necessary. The additional coordination mechanism we consider is profit sharing, using the Nash bargaining model. Based on our results, we derive optimal market strategies and identify probable paths for future research.     

Supplier selection-order allocation: A two-stage multiple criteria dynamic programming approach

This paper proposes a two-stage multiple criteria dynamic programming approach for two of the most critical tasks in supply chain management, namely, supplier selection and order allocation. In the first stage, to address multiple decision criteria in supplier ranking, the analytic hierarchy process (AHP) is employed. In the second stage, supplier ranks are fed into an order allocation model that aims at maximizing a utility function for the firm as well as minimizing the total supply chain costs, subject to constraints on demand, capacity, and inventory levels. A dynamic programming approach is crafted to solve the proposed bi-objective model.     

A two-stage fuzzy-AHP model for risk assessment of implementing green initiatives in the fashion supply chain

Green or environmental concerns are drawing more and more attention both in academia and industry. Careful deployment of green initiatives or policies could not only fulfil the requirements of environmental legislation but also lead to a competitive advantage for firms. Nevertheless, making optimal decisions in this regard is not easy. This is principally due to two reasons: (1) the qualitative nature of, and (2) the uncertainty associated with, the parameters involved in the decision-making process. Analytic hierarchy process could be a useful tool to tackle the first challenge because of its ability to handle both qualitative and quantitative variables (decision criteria). Unfortunately, this approach is inadequate at addressing the uncertainties common in real-life applications. This challenge is particularly noticeable in the fashion industry since demand is very volatile, and there are many uncertain variables associated with the whole supply chain. As a result, this paper blends fuzzy logic, which is a popular method of incorporating uncertain parameters into the decision-making process, with analytic hierarchy process to form a selection (decision-making) model for different green initiatives in the fashion industry. The rationale behind the model is to analyse the associated risk of different alternatives, subject to different factors, be they deterministic or not. A numerical example is included in this paper to demonstrate how the proposed model works.     

Games with incomplete information: A simplified exposition with inventory management applications

In most existing literature in supply chain management it is assumed that the players possess complete information about the game, i.e., the players' payoff (objective) functions are assumed to be common knowledge. For static and dynamic games with complete information, the Nash equilibrium and subgame perfect equilibrium are the standard solution concepts, respectively. For static and dynamic games with incomplete information, the Bayesian Nash equilibrium and perfect Bayesian equilibrium, respectively, are used as solution concepts. After presenting a brief review of the static and dynamic games under complete information, the application of these two games in inventory management is illustrated by using a single-period stochastic inventory problem with two competing newsvendors. Next, we illustrate the Bayesian Nash and perfect Bayesian equilibrium solution concepts for the static and dynamic games under incomplete information with two competing newsvendors. The expository nature of our paper may help researchers in inventory/supply chain management gain easy access to the complicated notions related to the games played under incomplete information.     

Market design in Chinese market places

The market design (MD) approach to institutional analysis provides the analytical tools to evaluate endogenous institution building in local market places irrespective of the institutional setting of the national economy. Implicit in this analysis of endogenous institution building at the market place level is the recognition of institutional diversity, which none of the conventional forms of institutional analysis can provide. We extend the MD approach from its original game theory perspective to examine three market places in China: township and village enterprises, equity joint ventures, and public utilities. We conclude that the MD approach (1) provides the analytical tools and criteria to evaluate whether or not market places are robust and sustainable, (2) links market behavior at the market place level, which is characterized by size, coordination, and trust problems, with general level considerations based on transaction costs, and (3) suggests that functioning market places are achievable, even if the formal institutions of the general economy are weak or partially missing. Our research has policy implications and opens new avenues for research into the emergence of markets.     

Decision models in global supply chain management

Integrative decision making is key to effective supply chain management (SCM). This article examines five illustrative supply chain decision models that demonstrate the importance of integrating the decisions across the supply chain. The models that are discussed illustrate the diversity of analytical approaches and their usefulness in managing global supply chain issues. The paper identifies potential areas of additional research where analytical modeling can generate useful insights. The paper also presents a short categorization of decision models from literature.     

A holistic network model for supply chain analysis

Supply chain researchers are experiencing a conceptual and analytical paradox. They are asked to move beyond dyadic analyses and investigate larger network effects with only a limited analytical toolkit. This research proposes the use of bilinear mixed-modeling to holistically analyze supply chain phenomena. Through this approach, researchers are able to account for multiple supply chain relationships, higher-order dependencies among member firms, and simultaneously evaluate covariates from buyer and seller perspectives. The model is validated through the lens of a pervasive supply chain problem commonly referred to as the bullwhip effect. A sample of firms from the US apparel industry in 2004 is analyzed and then the findings are confirmed using data from 2005. In addition to validating the model through the presence of the bullwhip effect, the bilinear model illuminates variables such as advertising, price deals, inventory turnover, and inventory backlogs that exacerbate or diminish inventory differences between firms in a supply chain. The results extend research on supply networks and supply efficiency to a more holistic level and show that higher-order dependencies are important drivers of supply chain phenomena.     

Game theoretical perspectives on dual-channel supply chain competition with price discounts and pricing schemes

This paper evaluates the impact of price discount contracts and pricing schemes on the dual-channel supply chain competition. Channel conflict occurs when the supplier enters the online direct channel. Traditional contracts normally require tedious administrational participation, full information of the cost structures, and other factors. The introduction of simple price discount contracts aims at providing easy implementation and effective coordination results. From supplier Stackelberg, retailer Stackelberg, and Nash game theoretic perspectives, we show that the scenarios with price discount contracts can outperform the non-contract scenarios. In addition, we show consistent pricing scheme can reduce the channel conflict by inducing more profit to the retailer. The leader in the games might, but is not guaranteed to, have advantages.     

A review of the extensions of a modified EOQ model for imperfect quality items

Imperfect items in the raw material and production stages of a supply chain directly impact the coordination of the product flow within a supply chain. In response to this concern, production and inventory lot sizing models, which incorporate imperfect items into their formulation have become an important and growing area of research. The contribution of Salameh and Jaber (2000) is one of the fundamental models on lot sizing when procured items are of imperfect quality. Over the past decade, there has been a noticeable amount of interest in the EOQ model for imperfect items that was set forth in Salameh and Jaber (2000). Several researchers have published adaptations and extensions of this original model that address supply chain coordination, quality improvement and yield management, and the impact of human error on production and inventory systems. In this paper, we summarize the current body of research that has extended the Salameh and Jaber (2000) EOQ model for imperfect items. Some possible future research directions are identified at the end of the paper.     

Fuzzy multiple criteria selection of government-sponsored frontier technology R&D projects

Selection of government-sponsored frontier R&D projects is made difficult by the coexistence of the conflicting participating parties, the availability of experts for new frontier technology review, and the ambiguity of new frontier technology. This paper presents a model that includes (1) using the analytical hierarchy process (AHP) method to integrate various expectations from different interest groups into evaluating objectives/criteria, (2) the group-decision method by technical experts based on the predetermined objectives/criteria, and (3) the fuzzy approach in scoring the subjective judgments of the experts. The results reveal that differences of weights toward each criterion exist among various groups. The government and academia care more about social benefits, the researchers are more concerned about intellectual properties, and the experts from industry emphasize the importance of feasibility. The method presented in this paper was applied at a national research institute in Taiwan. The results reveal that: (1) the approach can solve the disparity between the profound knowledge required for evaluation and the different expectation from various interest groups, (2) the fuzzy approach is suitable to frontier technology R&D project selection because of the vagueness of the nature of frontier technology and the difficulties in evaluating quantitatively and accurately.     

Mean-variance analysis of Quick Response Program

Quick Response Program (QRP) has been well established in fashion supply chains. It is known that QRP may not be equally good to all channel members and some measures have to be taken in order to achieve a win–win situation. However, little is known about the corresponding level of risk associated with QRP and some proposed measures. In light of this, we study QRP via a mean-variance (MV) approach. We illustrate how the measures such as price commitment policy, service-level commitment policy, and buy-back policy can be adjusted to achieve the MV win–win situation in which the channel members can be better off with considerations of both expected profit and risk. Numerical analyses are included and the analytical conditions for achieving both the supply chain channel coordination and the MV win–win situation are derived. Managerial insights are generated.     

The role of ERP tools in supply chain information sharing,cooperation, and cost optimization

The transaction based integrated Enterprise Resource Planning (ERP) software provides different tools that can support supply chain integration but at the same time it has several features that obstructs the integration with business partners. We concentrate on the inventory management aspects of supply chain coordination reviewing the recent quantitative modeling and organizational results available in literature. We summarize the results of a detailed numerical and sensitivity analysis based on our previously published models for supply chain cooperation and joint optimal ordering and shipment policies for the buyer and supplier. These results can be used in enterprise software to measure the potential monetary value of policy coordination, to promote cooperation, and minimize the total supply chain system cost. Our further goal is to combine quantitative tools with organizational and management factors, and to integrate them in a multi-level framework of policy coordination.     

Coordination of a supply chain with one manufacturer and multiple competing retailers under simultaneous demand and cost disruptions

This paper develops a coordination mechanism for a supply chain consisting of one manufacturer and n Cournot competing retailers when the production cost and demands are simultaneously disrupted. This differs from traditional supply chain coordination models under a static case and the case with only demand or cost disruption. The coordination mechanism with revenue sharing is considered, and the effects of production cost and demand disruptions on revenue sharing contract are discussed to investigate the optimal strategies of players with disruptions. The penalty cost is introduced explicitly to obtain the production deviation cost caused by the disruptions. In this study, it is obtained that the coordination contract considering the production deviation cost differs from that without disruption. Besides that, the disruptions may affect the order quantities, wholesale prices as well as revenue sharing contract. Then, the optimal strategies for different disruption levels under the centralized decision-making mode are proposed. Concerning the decentralized mode, the improved revenue sharing contract can be used to coordinate the decentralized decision-making supply chain effectively. Finally, the theoretical results are illustrated by conducting some numerical examples.     

Pricing decision for substitutable products with retail competition in a fuzzy environment

This paper studies the pricing problem of substitutable products in a supply chain with one manufacturer and two competitive retailers. The consumer demands and manufacturing costs are of uncertainty, which are described by fuzziness. Based on different market structures, one centralized pricing model and three decentralized pricing models are developed, and the corresponding analytical equilibrium solutions are obtained using the game-theoretic approach. Finally, numerical examples are presented to illustrate the effectiveness of the theoretical results, and to gain additional managerial insights.     

Remarks on Engineering Economy Studies from the Viewpoint of Statistical Decision Theory

Lack of credit during periods of financial stress can reduce sales in an entire supply chain. To reduce the reliance on external credit, we introduce a new financing framework in which key supply chain stakeholders accept delayed payment for a pre-agreed portion of their product or service. By doing so throughout the supply chain, each stakeholder must self-finance only their in-house activities—but not the cost of purchased components and services because those are in turn financed by their suppliers. Intended to account for only a small fraction of sales, this framework is limited to supplying customers who do not qualify for external financing. The payments from these customers are distributed among the value chain stakeholders according to an agreed-upon policy. These additional sales would otherwise be lost for lack of consumer credit. This approach increases sales and profitability for the entire supply chain and is especially advantageous during credit crunches. In addition to describing this new financing framework, this article places it in the context of other financing arrangements, provides an example with cash flow and net present value calculations, and identifies implementation challenges and characteristics of supply chains that are good candidates.     

经销商再制造的闭环供应链收益-费用契约协调研究

针对经销商从事再制造的闭环供应链最优决策及协调问题,考虑消费者对新产品和再制造品的接受程度不同,本文构建了集中决策和分散决策两种模式下闭环供应链差别定价模型。研究发现,分散决策会造成整个闭环供应链的效率损失;消费者接受度对闭环供应链系统中各方的最优决策及利润具有一定影响,并提出了收益共享-费用分担契约来实现闭环供应链的协调和效率优化。最后通过算例分析,进一步验证了本文所提出的协调机制对闭环供应链的有效性。     

A serial supply chain of newsvendor problem with safety stocks under complete and partial information sharing

We consider a supply chain where multiple members are serially connected. The decision is to determine the ordering quantity of a member to the next upstream member in the supply chain. The basic cost model is similar to the newsvendor problem with additional consideration to safety stock. This paper presents optimal approaches for coordination of the supply chain under both complete and partial information sharing in order to maximize the total expected benefit. For complete information sharing we develop an optimal coordination algorithm. For partial information sharing, we propose an optimal coordination algorithm based on the Alternating Direction Method and the Diagonal Quadratic Approximation Method. A numerical example is discussed to show the optimal convergence of ordering quantities and discuss the properties of the proposed algorithms.