Scheduling commercial vehicle queues at a Canada-US border crossing

Using the context of queue operations at a major Canada-US commercial border crossing for truck-borne trade flows, we report on a computer simulation study to predict the likely impacts of smoothing those flows. We quantify the operational and resource efficiencies of smoothing for trans-border trucking companies and their trans-border supply chain partners as well as for government authorities with regulatory jurisdiction at border crossings. Our study’s major conclusion is that smoothing can achieve queue performance levels that, in the absence of smoothing, would require significant investment in truck processing capacity at border crossings.     

Optimizing inventory decisions in a multi-stage multi-customer supply chain

Most supply chain models focus on two-stage chains in which vendors supply material to one customer. In this paper, we formulate a three-stage supply chain model where a firm can supply many customers. We deal with three inventory coordination mechanisms between chain members and solve a cost minimization model for each. We show that some of the coordination mechanisms can result in a significantly lower total cost than matching production and delivery along the chain. We provide some insights into when the added complexity of the second and third coordination mechanisms lead to significant cost reductions.     

Supply chain design under quality disruptions and tainted materials delivery

Events such as the 2008 Heparin tragedy, in which patients lost their lives due to tainted pharmaceuticals, highlight the necessity for supply chain designers and planners to consider the risk of even low probability incidents in supply chains. The goal of this research is to design a single-period, single-product supply chain model with capacitated facilities to hedge against the possibility of sending tainted materials to consumers. Given that our mixed-integer stochastic model is NP-hard, we develop efficient heuristic and metaheuristic algorithms to obtain acceptable solutions. Computational experience is presented and discussed.     

Supplier hoarding,government intervention,and timing for post-disaster crop supply chain recovery

This work presents a multi-methodological approach to address the issue of post-disaster crop supply chain recovery under the influences of government intervention and supplier hoarding intention. A conceptual model which characterizes the antecedents of supplier hoarding intention is proposed, and validated using survey data. Grounded in the empirical study, an analytical model is then proposed for decision analysis of a two-tier crop supply chain recovering from post-disaster supply disruptions. Analytical results indicate that hoarding behavior reduces the time taken by supply chain members for supply recovery; and however, contributes to mixed effects on the expected profits of supply chain members.     

Coordination in a single-vendor multi-buyer supply chain by synchronizing delivery and production cycles

This paper proposes a coordinated single-vendor multi-buyer supply chain model by synchronizing delivery and production cycles. The synchronization is achieved by scheduling the actual delivery days of the buyers and coordinating them with the vendor’s production cycle whilst allowing the buyers to choose their own lot sizes and order cycles. A mathematical model for our proposed coordination is developed and analyzed. The results of our three numerical examples show that the synchronized cycles policy works better than independent optimization as well as restricting buyers to adopt a common order cycle.     

Uncertainty propagation in a supply chain or supply network

A supply chain is characterized by uncertain demands (demand-side uncertainty) and uncertainties associated with the performances of the production facilities (supply-side uncertainty). In this paper, a method is proposed to plan production in a supply chain with a multi-echelon supply process with unreliable production facilities working in markets with uncertain demand. In such a system it is necessary to consider the global and cumulative effects on the performance of the entire supply chain. We introduce the salient features of uncertainty propagation in supply chains and demonstrate their impact quantitatively using a test problem from the automotive industry.     

Supply chain network design under profit maximization and oligopolistic competition

In this paper, we model the supply chain network design problem with oligopolistic firms who are involved in the competitive production, storage, and distribution of a homogeneous product to multiple demand markets. The profit-maximizing firms select both the capacities associated with the various supply chain network activities as well as the product quantities. We formulate the governing Nash–Cournot equilibrium conditions as a variational inequality problem and identify several special cases of the model, notably, a generalization of a spatial oligopoly and a classical oligopoly problem to include design capacity variables. The proposed computational approach, which is based on projected dynamical systems, fully exploits the network structure of the problems and yields closed form solutions at each iteration. In order to illustrate the modeling framework and the algorithm, we also provide solutions to a spectrum of numerical supply chain network oligopoly design examples.This paper makes a contribution to game theoretic modeling of competitive supply chain network design problems in an oligopolistic setting.     

Multistage optimization of the supply chains of biofuels

In this study, a mathematical model that integrates spatial and temporal dimensions is developed for strategic planning of future bioethanol supply chain systems. The planning objective is to minimize the cost of the entire supply chain of biofuel from biowaste feedstock fields to end users over the entire planning horizon, simultaneously satisfying demand, resource, and technology constraints. This model is used to evaluate the economic potential and infrastructure requirements for bioethanol production from eight waste biomass resources in California as a case study. It is found that, through careful supply chain design, biowaste-based ethanol production can be sustained at a compatible cost around $1.1 per gallon.     

Evolutionary variational inequalities and applications to complex dynamic multi-level models

In this paper we consider a supply chain network model with three tiers of decision-makers (manufacturers, retailers, and consumers) in the case when prices and shipments are evolving on time. Moreover, we assume that excesses of production and excesses of demand of the commodity are present. For such a framework we furnish, using the infinite dimensional duality theory, the equilibrium conditions for the representatives of each tier of the supernetwork, the time-dependent variational formulation governing the complete supply chain supernetwork, and we provide some existence theorems and a numerical example.     

Optimizing inventory decisions in a multi-stage multi-customer supply chain: A note

In this paper, we propose an n-stage-multi-customer supply chain inventory model where there is a company that can supply products to several customers. We formulate the model for the simplest inventory coordination mechanism which is referred to as the same cycle time for all companies in the supply chain. We conclude that it is possible to use an algebraic approach to optimize the supply chain model without the use of differential calculus.     

供应链的战略管理模型研究

强调成本的有效性供应链和强调时间反应速度的反应性供应链是两种完全不同的供应链战略。企业在强调成本时不能完全忽略供应链的时间效用,同样在强调反应速度时也无法完全忽视成本的影响,因此通过对供应链战略的分析,对成本和时间赋予一定的权重,建立综合成本和反应速度的供应链战略模型,并通过实例对模型进行了验证。     

Global supply chain design: A literature review and critique

In this paper, we review decision support models for the design of global supply chains, and assess the fit between the research literature in this area and the practical issues of global supply chain design. The classification scheme for this review is based on ongoing and emerging issues in global supply chain management and includes review dimensions for (1) decisions addressed in the model, (2) performance metrics, (3) the degree to which the model supports integrated decision processes, and (4) globalization considerations. We conclude that although most models resolve a difficult feature associated with globalization, few models address the practical global supply chain design problem in its entirety. We close the paper with recommendations for future research in global supply chain modeling that is both forward-looking and practically oriented.     

Robust supply chain strategies for recovering from unanticipated disasters

Recovering from unanticipated disasters is critical in today’s global market. This paper examines the effectiveness of popular recovery strategies used to address unpredictable disasters that derail supply chains. We create a formal model to portray dynamic operational performance among supply chain firms facing disruptions caused by natural and man-made disasters. Our analysis shows that a supply chain recovers best if member firms adopt a radical, rapid, costly recovery strategy that immediately resolves the disruption. This observation is robust to various resource consumption requirements. We apply our methodology in the case of Taiwan’s 2011 food contamination scandal and provide managerial insights.     

Robust optimization for United States Department of Agriculture food aid bid allocations

The U.S. Department of Agriculture (USDA) currently uses a bidding system to determine carriers and suppliers that would partner in providing food aid annually in response to global emergencies and famine. We mimic the USDA approach via a robust optimization model featuring box and ellipsoid uncertainty frameworks to account for uncertainties in demand, supplier and carrier bid prices. Through a case study utilizing historical invoice data, we demonstrate our model applicability in improving ocean carrier and food supplier bid pricing strategy and similar supply chain network optimization problems. Through a validation algorithm we demonstrate the value of our robust models.     

The environmental benefits of changing logistics structures for fresh vegetables

The transport phase is one of the crucial stages that can be improved to reduce the environmental impact of the fresh fruit and vegetable supply chain. In this paper, we calculate the environmental impact of feasible logistic alternatives for the above-mentioned supply chain so as to identify the type of transportation that incurs the lowest environmental costs. Specifically, we consider the early potato supply chain as a case study, as it involves one of the main fresh vegetables exported from Italy. Consumers' willingness to pay for the environmental impact of different logistic chains was obtained through life cycle assessment. Our results show that rail transport could reduce environmental impact in terms of tons of oil equivalent, environmental loads, and fuel consumption while ensuring reasonable shipment times. Development of an efficient rail transport system would be positively considered by consumers, enhancing their preferences for Italian products.     

Inter-organizational relationships and knowledge sharing in green supply chains—Moderating by relational benefits and guanxi

This paper presents a new research model to examine the factors influencing the knowledge sharing and implementation in inter-organizational relationships. In this study, we examine how relational risk affects the willingness to share knowledge and how this association is affected by the tangible relational value (relational benefits) and intangible relational value (guanxi). Data are collected from 436 green manufacturing firms that are among the top 1000 Taiwanese manufacturing firms of 2008 listed by Business Weekly. Relational risk is found to be negatively associated with willingness to share knowledge. Our results show that relational benefits and guanxi between partners improve the negative effect of relational risk on knowledge sharing. The findings of the study provide useful insights into how green supply chain members should reinforce their relational benefits and guanxi activities that would improve their value-based relationships, in order to enhance the environmentally knowledge sharing for the green supply chain as a whole.     

The e-supply chain portal: a core business model

Information technology can help to overcome the problems that plague many supply chains. Electronic exchange of information leads to reduction of errors and increased efficiency of the work processes. When one company can use the information of other companies in the supply chain, the negative effects of uncertainty can be mitigated in theory. In practice, however, the exchange of information between companies is not as easy as it seems. Many different systems and standards are used, the number of peer-to-peer relations with other companies in the network is usually too large to manage, most systems are not open for easy exchange of information with other systems, and most companies are very reluctant to share information with other companies in the first place.A portal looks like a good solution to overcome these problems. Standardized interactions with one portal are easier to manage than are many peer-to-peer relations. The portal can take the role of a trusted party. What is needed to accomplish portal effectiveness is a review of the business processes when dealing with other companies. In this paper, we advocate a radical simplification of these business processes, and provide support for the end-to-end character of the supply chain in real time. Specifically, we report on a pilot project for the US Department of Defense to create a portal for supply chain integration. The project showed the feasibility of real-time support for end-to-end supply chain management in a complex organization.     

An integrated vendor–buyer model with stock-dependent demand

We develop an integrated vendor–buyer model for a two-stage supply chain. The vendor manufactures the product and delivers it in a number of equal-sized batches to the buyer. The items delivered are presented to the end customers in a display area. Demand is assumed to be positively dependent on the amount of items displayed. The objective is to maximize total supply chain profit. The numerical analysis shows that buyer–vendor coordination is more profitable in situations when demand is more stock dependent. It also shows that the effect of double marginalization provides a link between the non-coordinated and the coordinated case.     

Reprint of “Linking rival and stakeholder pressure to green supply management: Mediating role of top management support”

Drawing upon the Schumpeterian view of competition and stakeholder theory, the purpose of our study is to examine how issues of rivalry and stakeholder pressure motivate firms to implement green supply management practices. We also consider the role of top management support as an important enabler to how firms react to competitive pressures to pursue green supply management practices. Our model is tested using a sample of supply chain professionals. Our results indicate that environmental pressure from rivals and stakeholders influences green supply management implementation through the mediating role of top management support for environmental initiatives.     

The impact of item substitutions on production–distribution networks for supply chains

This study investigates the effects of various factors relevant to item substitution strategy on two-echelon production–distribution networks in decentralized supply chains. The item substitution strategy replaces preset items with alternatives to fulfill customer demands. The independent factors for the substitution strategy include substitution scope and available options. The moderators for the strategy include the dual sourcing strategy, substitution amount, and the echelons of the production–distribution network. The results of the experiment show that the item substitution strategy modulated by three moderators improved supply chain profit compared to cases where the strategy was not used.