一个能源供需网络演化模型

通过构造一个简化的能源供需网络演化模型,从基本上刻画出中国目前的能源供需现状。在该模型中,供应节点的度分布反映了能源供应企业的市场占有份额。数值模拟结果表明,能源供需网络中供应节点的顶点度近似服从幂率分布,这说明能源供需网络具有无标度性。最后,给出了一些关于能源供需策略的建议。     

基于成本-收益分析的逆向供应链网络演化机制分析

不同于发达国家TPT(第三方回收)的逆向供应链模式,我国逆向供应链具有无标度网络特征,其中大多数逆向供应链下游企业是走街串巷的个体商贩及其家庭作坊.本文提出基于成本-收益分析的我国逆向供应链网络演化机制.其中,废品回收站点需要支付固定的生产场所租金和投资购买专业生产设备,该固定成本可以在回收废品数量中均摊.当回收站点选择下游家庭作坊(或流动商贩)的最优数量时,将依据成本-收益分析获得最大化利益.最后,广东清远市电子产品废弃物回收网络的案例,以及NetLogo平台下数值仿真结果,较好地验证了理论分析结果.     

企业信用内生网络模型及其演化研究

本文考虑上游企业和下游企业两个部门,通过构建企业内生网络模型研究企业间信用关联内在形成机制及其演化特征。通过对内生网络模型仿真研究,结果表明本文构建的模型重现了现实企业系统存在的一些特征：企业信用网络度分布服从幂律分布,该网络具有无标度特征;较长的合并周期则能更好地反映企业间信用关系,且随着合并周期变大,网络密度也显著增大;企业资产规模分布具有幂律尾部特征,企业资产增长率随时间演化逐渐呈收敛状,且其概率分布近似于正态分布。     

住房市场系统复杂网络模型研究

将系统科学和复杂网络理论相结合,建立了包含银行、房地产开发企业和购房消费者三级节点的住房市场系统复杂网络模型,刻画了住房市场系统的结构特性和动态演化特性,并通过模拟仿真上海住房市场交易变动情况,体现了住房市场的客观规律。研究提出的住房市场复杂网络模型为住房市场研究提供了新的方法,克服了以往研究模型由于数据的有限性所导致的、复杂系统过度线性化近似和动态性研究不足的问题,在此基础上开展实证研究具有重要现实意义。     

基于仓室模型的危机蔓延建模与演化分析

以传染病传播为例讨论了基于经典仓室模型的危机蔓延过程建模,然后比较了经典仓室模型在不同网络拓扑结构假设下的参数设置,最后建立了一个具有普适性的仓室演化模型,并在无标度网络环境中进行了危机蔓延的模拟演化.演化结果显示了推行各类危机防控措施的必要性和合理性,同时也从无标度网络出发为研究传统危机防控措施提供了新的思考视角.     

考虑服务水平的供应链网络动态模型研究

本文建立了一个由多个供应商和多个零售商组成的供应链网络动态模型,利用定量手段刻画了制造商与制造商间、零售商与零售商间博弈的动态行为过程;通过制造商和零售商提供的服务水平以及产品的零售价格较为贴切的刻画消费者的选择偏好;充分考虑了需求随机产生的库存以及缺货情况;并在单调性条件下利用动态投影系统的相关理论分析了模型的稳定性.最后,通过算例验证了模型的合理性.     

基于供应链网络的商业模式创新研究

商业模式研究已经成为当前研究的热点.在已有成果的基础上,本研究引入模块化与供应链网络理论,构建了商业模式创新的环境模型,分析了商业模式创新的源动力与路径,以期为商业模式创新提供指导.     

基于动态无标度网络的信息策略与羊群行为演化研究

传统的人工股票市场效率不高,对投资者的异质性假设缺乏经济学含义,更没有考虑市场中广泛存在的羊群行为的影响。本文以国外期权市场异质信息交易者模型为基础,结合互联网金融特点在传统人工股票市场中引入异质信息策略与动态无标度人际关系网络刻画的羊群行为构建出新的人工股市模型,进行投资者的信息策略与羊群行为演化研究,对比分析不同机制的引入所带来的影响,揭示动态关系网络环境下信息策略演化结果。研究发现：一方面,信息策略演化机制的引入加快了市场均衡速率并提高了市场效率,同时也大大降低了投资者财富水平并拉大了财富差距;信息策略与羊群行为的演化并不会导致投资者完全向内幕信息交易者聚集,高、低信息档次投资者明显居多且其他信息档次投资者仍然存在。另一方面,动态关系网络下羊群行为的引入增强了投资者的被传染程度,并进一步缩小了财富差距且显著提高了内幕信息的扩散质量与效率。所以,互联网关系网络环境下高、低信息档次投资者占据相对优势,但其他信息档次投资者并不会被挤出市场;监管部门在努力寻求高市场效率的同时,也应在投资者财富与社会总财富等方面进行适当权衡。     

供应链道德风险的演化规律

建立了以人为粒度(agent)的供应链道德风险有向多局域世界网络模型,给出了供应链道德风险的定义,确定了供应链道德风险复杂网络中人与人之间相互作用的交互规则及网络的演化规则,采用复杂网络分析方法,证明了供应链道德风险复杂网络拓扑特性的演化规律——其网络服从幂律分布,供应链道德风险多局域世界复杂网络满足无标度特性,该幂律取决于供应链特性的大小.     

适应性供应链的复杂网络模型研究

面对经济全球化、顾客需求的多样化和众多不确定性因素,传统的供应链必须向适应性供应链转变。适应性供应链已经开始引起企业和学术界的关注。本文探讨了适应性供应链的概念,指出学习是提高供应链适应能力的一个重要途径,并提出了适应性供应链的一个初步模型框架。然后建立了供应链的复杂网络演化模型,导出了其基本统计规律,最后给出了仿真结果。研究对于探讨供应链的复杂动态演化规律具有一定意义。     

供应链中的批量与信用期联合决策研究

信用支付契约是使供应链各方达到协调的重要手段。本文在单个制造商和单个零售商组成的两级供应链系统下,建立了制造商和零售商的库存控制模型,提出了联合决策零售商的订货批量,以及制造商的生产批量和定期信用支付期的启发式算法。给出了利润分配方案,以使供应链达到协调。最后,本文通过算例验证了模型和算法的有效性,为运用信用支付契约协调供应链提供了理论依据。     

Power Structure and Profitability in Assembly Supply Chains

This paper studies the impact of supply chain power structure on firms' profitability in an assembly system with one assembler and two suppliers. Two power regimes are investigated—in a Single Power Regime, a more powerful firm acts as the Stackelberg leader to decide the wholesale price but not the quantity whereas in a Dual Power Regime, both the price and quantity decisions are granted to the more powerful firm. Tallying the power positions of the three firms, for each power regime we study three power structures and investigate the system's as well as the firms' preference of power. We find that when the assembler is the most powerful firm among the three, the system‐wide profit is the highest and so is the assembler's profit. The more interesting finding is that, if the assembler is not the most powerful player in the system, more power does not necessarily guarantee her a higher profit. Similarly, a supplier's profit can also decrease with the power he has. These results contrast with the conclusion for serial systems, where a firm always prefers more power. We also find that when both suppliers are more (less) powerful than the assembler, it can be beneficial (indifferent) for everyone if the two suppliers merge into a mega supplier to make decisions jointly. When the assembler is more powerful than one supplier and less so than the other, it is always better for the system to have the two suppliers merge, and for each individual firm, merging is preferred if the firm becomes the more powerful party after merging.     

供应链柔性批量订货契约研究

为实现批量订货与柔性采购相结合的目标,用一定折扣换取一定的柔性,从而实现供应链内部的协调及风险的分摊。在供应链中,从卖方角度,希望买方以稳定的(最好是不变的)订货量订货,以保证稳定的销售,减小牛鞭效应的影响,为此,卖方将对超过约定订货量的部分商品收取额外费用(或取消价格折扣);另一方面,从买方角度,由于下游不稳定的市场需求,买方希望没有约定订货量的约束,而是根据实际的市场需求在当期确定订货量。双方折中的结果是,买方必须许诺一个基本的订货量,但拥有一定次数和范围的改变订货量的机会。针对这一问题,建立了一种带柔性的批量订货契约模型,并通过仿真验证了模型能够节约订货成本,实现供应链中风险的重新分配。     

Regulatory Trade Risk and Supply Chain Strategy

Trade regulations are an important driver of supply chain strategy in many industries. For example, the textile, paper, chemical, and steel industries grapple with significant levels of non‐tariff barriers (NTBs) such as safeguard controls and countervailing duties. We explore three often observed supply chain strategies in industries subject to NTBs; direct procurement, split procurement, and outward processing arrangements (OPAs). We characterize the optimal procurement quantities for each of these three strategies, and examine how industry and country characteristics influence the firm's strategy preference. For example, we establish that the direct and split strategy profits increase in the NTB price variance but decrease in the mean price. These effects are sufficiently large that NTB price characteristics can dictate which supply chain strategy is preferred. Both the cost disadvantage and lead‐time advantage of domestic production are also significant influencers of the preferred strategy, as is the domestic‐country mandated production constraint associated with the OPA strategy.     

Impacts of Power Structure on Supply Chains with Uncertain Demand

In this study, we use a game‐theory‐based framework to model power in a supply chain with random and price‐dependent demand and examine how power structure and demand models (expected demand and demand shock) affect supply chain members' performance. We demonstrate that whether a firm benefits from its power depends on the expected demand model but not on demand shock model. A firm benefits from its power only for linear but not for constant elasticity expected demand. The impact of power structure on supply chain efficiency depends on the models of both expected demand and demand shock. With additive shock, supply chain efficiency is highest (lowest) when neither firm dominates for linear (constant elasticity) expected demand. With multiplicative shock, the supply chain efficiency is highest with a power retailer (manufacturer) for linear (constant elasticity) expected demand. The manufacturer always benefits from a reduction in demand uncertainty. However, the retailer loses (benefits) from demand uncertainty reduction for linear (constant elasticity) expected demand. With a power retailer, the retail price is always on the higher end for linear expected demand, and the customer service level is the lowest for constant elasticity expected demand. Consequently, consumers do not necessarily benefit from a power retailer.     

Demand Forecast Sharing in Supply Chains

This paper examines the incentives of a manufacturer and a retailer to share their demand forecasts. The demand at the retailer is a linearly decreasing function of price. The manufacturer sets the wholesale price first, and the retailer sets the retail price after observing the wholesale price. Both players set their prices based on their forecasts of demand. In the make‐to‐order scenario, the manufacturer sets the production quantity after observing the actual demand; in the make‐to‐stock scenario, the manufacturer sets the production quantity before the demand is realized. In the make‐to‐order scenario, we show that sharing the forecast unconditionally by the retailer with the manufacturer benefits the manufacturer but hurts the retailer. We also demonstrate that a side payment contract cannot induce Pareto‐optimal information sharing equilibrium, but a discount based wholesale price contract can. The social welfare as well as consumer surplus is higher under the discount contract, compared with under no information sharing. In the make‐to‐stock scenario, the manufacturer realizes additional benefits in the form of savings in inventory holding and shortage costs when forecasts are shared. If the savings from inventory holding and shortage costs because of information sharing are sufficiently high, then a side payment contract that induces Pareto‐optimal information sharing is feasible in the make‐to‐stock scenario. We also provide additional managerial insights with the help of a computational study.     

不同交叉销售结构情境下竞争供应链运营决策研究

不同的销售主体可以销售不同的产品数量。考虑竞争供应链系统由两个制造商和两个零售商组成,下游每个零售商都可以选择垂直上游制造商或者对方的制造商进行产品订购,构建了排他性、单交叉和双交叉三种销售模型,研究不同的竞争强度如何影响零售商订货策略、制造商批发价格和系统绩效。结果表明,当纵向竞争强度不变时,排他性销售下供应链的系统利润随着横向竞争强度的增大而逐渐减小,单交叉销售下供应链的系统利润随着横向竞争强度的增大而逐渐增大。而双交叉销售下供应链的系统利润的变化不仅与横向竞争有关,而且也与纵向竞争相关。     

Managing Disruption Risks in Supply Chains

There are two broad categories of risk affecting supply chain design and management: (1) risks arising from the problems of coordinating supply and demand, and (2) risks arising from disruptions to normal activities. This paper is concerned with the second category of risks, which may arise from natural disasters, from strikes and economic disruptions, and from acts of purposeful agents, including terrorists. The paper provides a conceptual framework that reflects the joint activities of risk assessment and risk mitigation that are fundamental to disruption risk management in supply chains. We then consider empirical results from a rich data set covering the period 1995–2000 on accidents in the U. S. Chemical Industry. Based on these results and other literature, we discuss the implications for the design of management systems intended to cope with supply chain disruption risks.     

供应链库存商业信用协调的研究

本文研究由一个供应商和多个客户构成的以供应商主导的两级供应链,建立了以平均库存成本为目标函数的供应链供需同步库存模型。为了保证合理的收益分配,促进各成员加入供需合作的积极性,在模型中引入了商业信用机制,由供应商给予客户商业信用期而产生的机会成本(或利益)来平衡各成员间的利益。理论分析显示该模型存在最佳订货次数和最佳生产时间间隔,使供应链的总平均库存成本最小。最后利用算例分析和敏感性分析验证了商业信用的有效性。