系统动力学的碳排放政策对供应链影响

随着低碳经济的发展,碳排放政策对于供应链的影响越来越受到关注。建立了基于系统动力学的单个供应商和销售商的供应链模型,并在此基础上引入强制排放和碳税两种碳排放政策。利用模型仿真,分析两种排放政策对于供应商、销售商及整个供应链的总成本和碳排放的影响。研究表明在强制排放模型中,不同的碳排放额度会使销售商选择不同的订货周期,发现合理的排放额度才能引导供应链双方降低排放,否则不仅达不到减排的目的,反而影响供应链效率;而在碳税模型中,提高碳税税率虽然会使政府获取一定的收益,但是实际上可能带来供应链总成本的上升和碳排放的增加,需要合理制定碳税税率引导绿色供应链发展。     

Modelling carbon trading and refrigerated logistics services within a fresh food supply chain under carbon cap-and-trade regulation

Carbon cap-and-trade regulation is widely adopted to reduce carbon emissions. Under this regulation, we propose a carbon trading mechanism considering refrigerated logistics services in a fresh food supply chain. In addition to supplying fresh food, the supplier offers refrigerated logistics services and overstocked carbon emission permits to the retailer. We study the decisions on the price of emission permits traded within the supply chain, the retail price and the price of refrigerated logistics services in different carbon trading options, without carbon trade, inner carbon trade, inner and outer carbon trade. Pricing strategies for fresh food, emission permits and refrigerated logistics services are provided for supply chain members. We also reveal the relationship between carbon trading and refrigerated logistics services, and investigate their joint influence on the supplier–retailer cooperative relationship. In addition, it is shown that with the implementation of a transfer payment mechanism, supply chain members are motivated to participate in the carbon trading mechanism, which has advantages including improved resource utilisation and more competitive supply chains.     

An optimization study of a palm oil-based regional bio-energy supply chain under carbon pricing and trading policies

Biomass residues due to their low bulk density typically require frequent transportation from biomass plantations in rural areas to conversion bio-energy power plants. This issue contrasts with environmental protection strategies, especially when power plants are facing different carbon reduction policies that enforce them to emit less than a given specific carbon amount. Although several researchers have investigated bio-energy supply chains concerning environmental policies, the majority of studies have been devoted to strategic decisions over a single planning period. This paper presents a multi-period bio-energy supply chain under carbon pricing (carbon tax) and carbon trading (cap-and-trade) policies at the tactical planning level. A mixed-integer linear programming model was adopted to optimize the proposed regional oil-palm biomass-to-bio-energy supply chain planning model. The numerical results indicate that when carbon pricing is in place when carbon tax increases linearly, carbon emissions’ reductions have a nonlinear trend, whereas both cost increase and carbon emissions’ reductions have a relatively upward trend in the carbon trading scheme. This paper also presents the sensitivity analysis of the proposed model regarding cost, emissions’ generation and supply chain performance. Finally, the paper recommends several significant practical implications and policy-making insights for managers and policymakers.     

Vendor-managed inventory with consignment stock agreement for single vendor–single buyer under the emission-trading scheme

This paper presents a joint economic lot size (JELS) model for coordinated inventory replenishment decisions under the vendor-managed inventory (VMI) with consignment stock (CS) agreement and an emission-trading scheme. The paper assumes a single product that flows along a two-level supply chain system, with a single vendor and a single buyer. The total cost of the system is the performance measure, which is the sum of the vendor’s and the buyer’s total costs. The total cost includes the set-up and order costs, inventory holding costs, greenhouse gases (GHG) emissions tax and penalty costs. A mathematical model is proposed to determine: (1) the vendor’s production lot size quantity; (2) the number of shipments sent by the vendor to the buyer in a cycle; and (3) the production rate that minimises the total cost of the supply chain. Some numerical examples are carried out, as well as comparisons with the traditional JELS model for a classic two-level supply chain. Results show that the performance of the system is better when it is operated under a VMI with CS agreement, which is capable of reducing the traditional inventory holding costs and, for some values of given parameters, the GHG emissions tax and penalty costs.     

Operational and environmental decisions for a two-stage supply chain under vendor managed consignment inventory partnership

Supply-chain-based organisations are nowadays facing intense pressure to abide to environmental regulatory requirements while they are striving to be responsive to customers’ needs at the least cost possible. As supply chain activities are among the top contributors to carbon emissions, several recent research works have investigated the impact of carbon regulation policies on economic and environmental supply chain performance. This paper presents integrated economic and environmental models for the one-vendor one-buyer supply chain problem under a vendor managed consignment inventory (VMCI) arrangement. Through the developed models, we study the impacts of two carbon reduction policies, namely carbon cap and carbon tax policies, on supply chain wide costs and carbon emissions. We first provide a much simpler and more compact formulation for the basic single-vendor single-buyer supply chain under VMCI agreement. We also present an environmental-based VMCI model where reduction of carbon footprint is considered as the only objective function. We then extend these two basic models to include each of the two carbon emissions reduction policies. We identify structural properties for the optimal solutions of the two hybrid economic and environmental models and propose algorithms to generate optimal solutions. The results of the computational experiments reveal that the implementation of carbon reduction policies, through carbon cap and carbon tax, may call for the adjustment of the vendor’s production and buyer’s delivery quantities to reduce carbon footprint without significantly increasing the operational costs.     

The Supply Chain Contract Design under Cap-and-Trade Mechanism with Free Riding

This paper studies the influence of free riding on enterprise product pricing and carbon emissions reduction investment, as well as the contract design to achieve supply chain coordination under the carbon trading mechanism. First, we discuss the situation where carbon emissions reduction investment affects the product price and income. It demonstrates that the optimal investment of the upstream manufacturer increases with the degree of the free riding of the downstream manufacturer. The upstream manufacturer can improve their carbon reduction investment and the whole supply chain achieves Pareto improvement when the investment cost sharing contract is introduced. Nevertheless, under the cost-sharing contract the optimal investment of the decentralized supply chain is still lower than that of the centralized supply chain, and only in some particular cases can the two types of supply chain achieve equal total profits. Then, we preliminarily explore the situation where the product price and income is influenced by carbon emissions reduction investment. The consequences indicate that the optimal investment of the upstream manufacturers in this situation is less than the former one's, and the transfer payment mechanism is able to improve the level of the supply chain overall carbon emissions-reduction. Moreover, compared to the former situation, the effects of free riding of the downstream manufacturer are even more serious. The conclusions can provide some intellectual support for manufacturing enterprises to make reasonable emissions reduction strategies and coordinate the supply chain existing in free riding.     

Coordinating a supply chain under uncertain demand and random yield in presence of supply disruption

A two-echelon supply chain involving one manufacturer and one retailer for a single product is considered in this paper. The end customers’ demand is assumed to be random. The production of the manufacturer is subject to random yield, and there is a possibility of supply disruption in which case no item from her can reach the retailer. The retailer has a backup supplier who is costlier but perfectly reliable, and is having a limit up to which he may deliver. In addition to placing an order to the manufacturer, the retailer is allowed to reserve a quantity from the backup supplier in the ordering period; he may buy up to the reserved quantity after realising actual market demand in the trading period. Aiming at studying the effects of the various uncertainties involved in the chain on the optimal decisions, we develop and analyse centralised and decentralised models. We also propose a contract mechanism to coordinate the chain and find threshold conditions for which the coordinated model would collapse. Numerical examples are provided to illustrate the developed model.     

碳抵消机制下的制造/再制造生产决策优化研究

为研究碳排放权抵消机制对制造/再制造生产决策的影响,分别构建基于配额和基于排放量两种抵消机制的生产决策优化模型。分析抵消上限、再制造品接受度对产量、企业利润、消费者剩余和社会总福利的影响。结果表明,抵消机制会提高新品产量并降低再制造品产量,增加企业利润、消费者剩余和社会总福利,以上变化幅度随抵消上限的提高先增大后减小。再制造品接受度较高时,最优解对抵消上限变化更敏感。政府应将抵消上限设定在低水平且谨慎调整,可通过适度牺牲企业利润提高社会福利。拥有高配额的企业在配额机制下运作更具效益,反之在排放量机制下更优。     

Joint decisions on inventory replenishment and emission reduction investment under different emission regulations

Carbon emission regulation policies have emerged as mechanisms to control firms’ carbon emissions. To meet regulatory requirements, firms can make changes in their production planning decisions or invest in green technologies. In this study, we analyse a retailer’s joint decisions on inventory replenishment and carbon emission reduction investment under three carbon emission regulation policies. Particularly, we extend the economic order quantity model to consider carbon emissions reduction investment availability under carbon cap, tax and cap-and-trade policies. We analytically show that carbon emission reduction investment opportunities, additional to reducing emissions as per regulations, further reduce carbon emissions while reducing costs. We also provide an analytical comparison between various investment opportunities and compare different carbon emission regulation policies in terms of costs and emissions. We document the results of a numerical study to further illustrate the effects of investment availability and regulation parameters.     

VMI下需求受库存和努力水平影响的供应链协调

针对一个实施VM I(供应商管理库存)的两级供应链,市场需求受供应商和零售商双重努力影响的问题,建立了基于协作关系的库存和努力水平决策模型。通过分析得出在分散决策下供应商选择的库存水平和零售商选择的努力水平均低于集中决策下的最优水平,供应链效率也较低。设计了一个成本分摊契约协调供应链。结果表明,该契约能将供应商和零售商紧密地联系在一起,且通过供应商和零售商的共同努力能获得比分散式决策下更大的利润。     

Uncertain supply chain network design considering carbon footprint and social factors using two-stage approach

Sustainable development has become one of the leading global issues over the period of time. Currently, implementation of sustainability in supply chain has been continuously in center of attention due to introducing stringent legislations regarding environmental pollution by various governments and increasing stakeholders’ concerns toward social injustice. Unfortunately, literature is still scarce on studies considering all three dimensions (economical, environmental and social) of sustainability for the supply chain. An effective supply chain network design (SCND) is very important to implement sustainability in supply chain. This study proposes an uncertain SCND model that minimizes the total supply chain-oriented cost and determines the opening of plants, warehouses and flow of materials across the supply chain network by considering various carbon emissions and social factors. In this study, a new AHP and fuzzy TOPSIS-based methodology is proposed to transform qualitative social factors into quantitative social index, which is subsequently used in chance-constrained SCND model with an aim at reducing negative social impact. Further, the carbon emission of supply chain is estimated by considering a composite emission that consists of raw material, production, transportation and handling emissions. In the model, a carbon emission cap is imposed on total supply chain to reduce the carbon footprint of supply chain. To solve the proposed model, a code is developed in AMPL software using a nonlinear solver SNOPT. The applicability of the proposed model is illustrated with a numerical example. The sensitivity analysis examines the effects of reducing carbon footprint cap, negative social impacts and varying probability on the total cost of the supply chain. It is observed that a stricter carbon cap over supply chain network leads to opening of more plants across the supply chain. In addition, carbon footprint of supply chain is found to be decreased in certain extent with the reduction in negative social impacts from suppliers. The carbon footprint of the supply chain is found to be reduced with increasing certainty of material supply from the suppliers. The total supply chain cost is observed to be augmented with increasing probability.     

存货影响销售量的两阶段供应链的VMI协调

研究在VMI环境下存货影响销售量的单供应商、单零售商的两阶段供应链的协调问题。建立了集中决策下的供应链模型,求出了整体供应链的利润函数;在分散决策下,采用收益共享契约对供应链进行协调,按Stackelberg博弈方式进行建模分析,发现收益共享契约无法协调供应链,即在利益分配上,与供应商相比,零售商获得了更多的供应链收益,而且分散式系统的收益始终低于集中决策下的水平;采用Nash协商对VMI供应链进行协调,完成了供应商和零售商收益的帕累托改进,不仅实现供应链的协调,而且达到了集中决策下的水平,最后通过算例进行了验证。     

基于碳信息不对称的两级供应链谎报行为

为研究供应链上下游企业间面临碳信息不对称风险时的最优谎报决策,运用Stackelberg博弈理论探讨制造商为主导的二级供应链博弈行为。结合碳排放交易机制下的新型利润模型,采用逆向求解法求解供应链参与者最优决策,并定性分析制造商和零售商的谎报行为以及谎报行为对供应链绩效的影响。研究表明,碳信息谎报与成本信息不对称情形具有明显差异。制造商不论是否谎报碳信息均能最大化自身利润,而零售商将低报碳排量信息。相比零售商不谎报情形,谎报反而能提高制造商与零售商利润,但此时供应链总利润仍低于供应链最优利润。制造商可通过收益共享契约协调供应链,且最优收益共享系数与谎报情形下零售商利润正相关。     

消费者绿色偏好、参考价格效应与供应链绿色创新

在竞争性的市场环境中引入消费者绿色偏好和参考价格效应,考虑这两种消费者行为特征如何交互作用于供应链上下游的绿色创新活动,进而影响绿色创新活动的绩效结果和利润分配。通过构建集中决策、分散决策和成本分担情境下的供应链绿色创新微分博弈模型,分别求得均衡条件下的供应链成员最优绿色创新努力水平与利润,并通过数值仿真结果进一步探讨消费者行为特征与供应链成员绿色创新努力水平之间的关系。研究表明,消费者偏好特征变化是激发供应链成员作出绿色创新努力的重要因素。制造商可以通过对供应商进行成本补贴来激发其绿色创新积极性,且当供应商边际利润与制造商边际利润的关系达到一定阈值,这种绿色创新成本补贴的激励效果更加显著,因而更有可能实现绿色创新基础上的供应链系统利润最优。     

Decision support system for vendor managed inventory supply chain: a case study

Vendor-managed inventory (VMI) is a widely used collaborative inventory management policy in which manufacturers manages the inventory of retailers and takes responsibility for making decisions related to the timing and extent of inventory replenishment. VMI partnerships help organisations to reduce demand variability, inventory holding and distribution costs. This study provides empirical evidence that significant economic benefits can be achieved with the use of a genetic algorithm (GA)-based decision support system (DSS) in a VMI supply chain. A two-stage serial supply chain in which retailers and their supplier are operating VMI in an uncertain demand environment is studied. Performance was measured in terms of cost, profit, stockouts and service levels. The results generated from GA-based model were compared to traditional alternatives. The study found that the GA-based approach outperformed traditional methods and its use can be economically justified in small- and medium-sized enterprises (SMEs).     

Coordinating a trust-embedded two-tier supply chain by options with multiple transaction periods

Trust widely works in supply chain practices and deeply affects supply chain decisions. Full trust in transactions and inaccurate demand forecasts are most likely to lead to biased decisions and low supply chain performances. Therefore, we propose a trust updating model to quantify decision-maker’s trust. The model presents the variation of trust over time and is helpful to evaluate decision-maker’s trust level in each transaction. In the model, a coordination mechanism with contract is designed to mitigate each supply chain partner’s ordering risk. Optimal order strategies of both manufactures and retailers in a supply chain under a bidirectional option contract are analysed in this paper. We find the manufacturer’s optimal production quantity is positively affected by penalty price in the contract and its bounds are given by simulation analysis. Our findings in this paper indicate that the proposed coordination mechanism with bidirectional option contract is profitable to all supply chain partners in long-term transactions. Meanwhile, the coordination mechanism helps the supply chain partners to catch up with marketing fluctuations and enhances the supply chain trust and partnerships. Finally, some simulation experiments are employed to obtain more observations.     

考虑运输能力约束的VMI补货发货动态批量研究

考虑由一个供应商和多个零售商构成的VMI供应链,在供应商运输能力有限、可采用外包策略的情况下,研究了动态需求环境下供应链补货及发货批量策略问题.分析得出供应商最优补货及发货期结构满足"零库存补货"性质,进而利用动态规划方法提出一个多项式算法优化补货及发货策略,其计算复杂度为O(T3),且通过平衡各种成本,可得每个发货周...     

碳限额交易政策下考虑消费者低碳偏好的供应链定价与协调

在碳限额交易政策及消费者低碳偏好条件下,针对两个制造商(一个碳减排、一个不进行碳减排)和一个零售商组成的二级供应链,分析了碳限额及消费者碳排放敏感系数对产品零售价和最优碳减排量的影响,并利用Shapley值法协调供应链。研究发现:最优碳减排量、产品零售价不仅依赖于碳限额和消费者碳排放敏感系数,还与初始碳排放量相关;清洁型制造商最优碳排放量为零;政府应该实行差异化碳限额交易政策,对于中间型及轻污染型制造商应该适当降低碳限额,对于重污染型制造商应该适当提高碳限额并给予企业碳减排补贴;对于清洁型及中间型制造商,政府应该提供低碳消费补贴;另外政府还应该加强节能环保宣传。     

Joint decisions for R/M integrated supply chain using system dynamics methodology

In the remanufacturing/manufacturing (R/M) integrated supply chain, the decisions of the manufacturer, the wholesaler, the retailer, the parts producer, the raw materials supplier, the collector, and the disassembly centre are interactional. In this paper, a system dynamics model is proposed to examine the long-term behaviour of the R/M integrated supply chain with reuse, remanufacturing, and recycling. The optimal decision sets of the remanufacturing ratio and the setup period of remanufacturing (r) are given, the joint decisions of all members of R/M integrated supply chain under optimal r are presented by the simulation results, and the impacts of optimal r on the joint decisions are analysed.     

Supplier selection under risk of delivery failure: a decision-support model considering managers’ risk sensitivity

This paper studies the problem of supplier selection and order allocation in a retail supply chain (comprising suppliers, a central purchasing unit and outlets) under disruption risk. The final demand is deterministic. Suppliers are located in different geographic areas, and supplies are subject to a positive probability of disruption. Different capacity and failure probabilities for each supplier are considered. Our analysis focuses on the insurance versus profitability trade-off faced by a supply manager who buys from suppliers for the outlets. Instead of determining optimal decisions given an objective function and the risk sensitivity of the decision-maker, we use a mixed integer linear programming approach to provide decision-making support that shows a supply manager the ‘elasticity of (expected) losses versus (expected) profits’. Under this model, and depending on the profit-and-loss targets, a supply manager of known risk sensitivity (i.e. risk aversion and loss aversion) can make better decisions when choosing suppliers. Moreover, taking into account, the impact of the share of fixed costs that must be covered by the operation, we consider the net values of expected profit and loss. We discuss the potential influence of the level of the firm’s fixed costs on the supply strategy. In particular, we show how the minimum value of the gross margin needed for the strategy’s profitability affects that strategy. A numerical application is conducted to illustrate the contribution of our decision-making support mechanism, and several managerial insights are obtained.