零部件产能不确定下装配商的订购-定价联合优化模型

针对零部件供应商产能不确定条件下装配商的订购与定价联合优化这一难题,运用随机非线性规划方法,以装配商期望利润最大化为目标,建立零部件订购量与最终产品定价的多维优化模型。通过求解给定价格时的最优订购量,将多维模型化为一维定价模型,随后给出关于最优定价的充分条件与必要条件,最终推导出订购与定价的最优决策。通过数值算例验证了模型结论并进一步探讨不确定产能的影响。研究结果表明,最优价格大于某个门槛价格,而尽管存在产能不确定性,装配商将按等比例订购零部件,并且其订购量等于最优价格对应的需求量。     

基于快速响应及成本控制的风场备件管控模型

研究风场备件精益管理问题,建立风场备件最优订货量模型、最优库存分配模型、最优响应方式模型。对模型进行数值分析得出结论:备件价格及残值不变时,最优订货量及期望总成本随缺货成本增加而增加;备件价格及缺货成本不变时,最优订货量随备件残值增加而增加,期望总成本随备件残值增加而下降;备件残值及缺货成本不变时,最优订货量随备件价格增加而下降,期望总成本随备件价格增加而增加。备件响应方式主要依赖于运输成本、备件安装提前期及备件响应时间的间接损失,间接损失越大,越倾向于快速运输方式。备件服务期望成本随风场需求波动增加而增加;将需求波动小的风场的部分备件储存于中心库,能降低期望成本。最后分析了前三条模型假设不满足时的结果调整。     

损失规避偏好下的供应链生产柔性决策

研究损失规避偏好下的供应链生产柔性问题。通过建立供应链期望效用模型,得到损失规避决策偏好下供应链最优生产量(订购量)和所需最大生产能力,引入生产柔性决策,得到损失规避决策偏好下最优生产柔性应满足的条件。同时分析损失规避系数对最优生产量(订购量)、所需最大生产能力、最优生产柔性水平、期望效用以及成本柔性系数的影响情况。本文结论为损失规避偏好的供应链提供最优的生产柔性决策,同时证明对于损失规避程度相对较大的供应链来说,会选择较高的生产柔性水平。     

带有免费送货选择的最优订货策略

有条件的免费送货已成为最有效的营销手段之一,越来越多的公司尤其是电子商务公司开始向一次订购量超过最小免费送货量的买家提供免费送货服务.研究了当供应商提供免费送货选择时零售商在确定需求和随机需求两种情况下的最优订货策略问题,并用导出的最优订货策略和数值试验分析了最小免费送货量及运费对零售商最优订货策略的影响.     

基于截断需求的分布鲁棒报童问题

在实际库存决策中,通常我们只能观察到销售量而非真实需求量,这导致了库存决策的截断需求问题——部分需求信息被库存水平所截断.本文在报童问题设置下首次提出使用条件分布鲁棒优化技术来处理截断需求信息.具体而言,基于历史销售数据,我们考虑了包含需求条件分布矩信息的分布不确定集,进一步提出将库存状态信息引入该分布不确定集,并导出了两类模型的闭式解:1)在基于均值-支撑集的分布不确定集下,支撑集的上下界决定了分布鲁棒报童模型的闭式解;2)在基于均值-方差-支撑集的分布不确定集下,期望、方差以及订货价与零售价共同决定了分布鲁棒报童模型的闭式解;3)随着订货价与零售价之比增大,分布鲁棒报童问题的最优订货数量降低.实验结果表明:当订货价与零售价之比处于某一范围时,截断需求信息可以提高分布鲁棒报童模型的期望收益,并且随着截断水平增加,提升收益率增加.     

考虑流通损耗的生鲜农产品零售商期权订货策略

针对生鲜农产品在流通中产生巨大损耗的特性,引入期权合同研究单周期两阶段的零 售商最优订货策略. 分别建立向单个供应商订购期权和同时向两个供应商订购期权 的订货模型,以最大化期望利润为目标,得到零售商的最优订货量和最大期望利润 都存在并且是唯一的. 通过模型比较得到: 零售商同时向两个供应商订货时的最优 总订货量大于等于分别向单个供应商订货时的最优订货量,零售商同时向两个供应 商订货时的最大期望利润大于分别向单个供应商订货时的最大期望利润. 由数值分 析得到: 向两个供应商订货的最大期望利润与产品损耗率、期权成本差价和期权 执行价格差价均成反比.     

部分信息下联合鲁棒定价、订货决策的报童模型

信息完全下的经典报童模型是单周期库存管理的核心控制方法，联合定价、订货决策是提高报童模型运作效率的主要手段. Scarf创造性地构建了部分信息下的鲁棒报童模型，但鲁棒联合定价、订货问题由于其困难程度，长期困扰着运作管理学者. 本论文在“做和型”随机价格需求函数条件下部分地解决了该问题. 在报童仅获知不确定需求的均值与方差的假设下，我们建立了Worst-case型的鲁棒联合定价、订货模型，并在适当的条件下给出了联合决策的闭环最优解. 数值实验证实了联合的鲁棒定价与订货决策较大幅度地改善了Scarf鲁棒订货模型的运作效率. 该模型能较好地适应于新产品供应链等信息缺失下的企业运作管理.     

基于二次订货与回购的供应链网络应对需求扰动

各类频发的突发事件经常导致需求扰动,使供应链网络难以正常运作和应对.分析了批发价合同和提前订货策略下生产商之间、零售商之间的竞争行为,得到供给市场和零售市场的均衡模型;由价格平衡和供需平衡条件得到需求市场均衡模型;进而建立了多商品流三层供应链网络均衡的变分不等式模型.当突发事件导致需求扰动时,原供应链网络均衡状态难以维持,供需矛盾将引起需求市场价格波动,导致供应链运作风险和社会福利损失.假定生产商提供回购合同、并允许零售商二次订货,分析了需求扰动后供给市场、零售市场和需求市场均衡的变化,建立了可应对需求扰动的供应链网络均衡模型.仿真算例验证了模型的合理性和有效性.     

基于多变量高斯过程模型的贝叶斯建模与稳健参数设计

针对模型预测偏差和波动的稳健参数设计问题,在多变量高斯过程(multivariate Gaussian process,MGP)建模的框架下,结合质量损失函数和非线性优化约束方法构建一个新的多响应优化模型.首先,利用成对估计方法获得超参数近似值,构建多变量高斯模型;其次,结合MGP模型特征,构造充分考虑响应波动因素的质量损失函数.利用蒙特卡罗模拟方法,获得响应落入指定区间的期望概率;然后,以期望概率为约束,结合本文所提质量损失函数建立优化模型;最后,利用全局优化算法进行寻优,获得考虑响应期望概率的优化结果.实际案例和软件仿真表明,该方法综合权衡了预测偏差和预测波动引起的不确定性对优化结果的影响.获得了兼顾质量损失和期望概率最优均衡解,从而实现稳健参数设计.     

基于需求预测信息更新的零售商三阶段采购最优策略

考虑存在顾客需求预测信息更新下零售商最优订货策略,研究了三阶段订货模型,零售商首先在第1阶段订货,然后在第1和第2阶段之间实现需求预测信息更新,并在第2阶段调整第1阶段的订货水平,第3阶段顾客需求实现,此时零售商可以从实时市场购货以满足前2阶段订货不足的部分.给出了零售商的最优订货策略,并分析了需求预测信息和实际需求满足二维正态分布时,它们之间的相关系数对采购决策和零售商期望利润的影响.提出了计算最优采购策略的算法并证明了其收敛性.说明了预测信息和实际需求联系越密切,零售商第1阶段最优订货水平越高,同时零售商利润越高;如果信息和实际需求之间的相关系数确定,那么第1阶段最优订货水平就确定,而第2阶段订货水平和需求预测信息与第1阶段订货量有关.     

MANUFACTURER’S UNIFORM PRICING AND CHANNEL CHOICE WITH A RETAIL PRICE MARKUP COMMITMENT STRATEGY

The paper studies channel choice decisions in a multi-channel supply chain under a strategy where there is an ex-ante commitment made on the retail price markup. The market demand is uncertain and dependent on the price and sales efforts. The results show that in any channel structure, when making order decisions the retailer only examines the price ratio and the fluctuation size of random demand, rather than the channel cost and the retailer＇s marketing efficiency. When the retail price rises, the manufacturer is willing to increase inventory quantity for direct sales, because the manufacturer＇s profit margin is higher in direct channel. The increase in demand fluctuation only affects the degree of channel preference but doesn＇t change the manufacturer＇s channel choice. No matter in which level the price ratio is, when the sales efficiency of retail channel is not high or the demand proportion of direct channel is low, the manufacturer and the retailer will be both apt to choose a dual-channel structure. Then adding a direct channel becomes a marketing strategy, rather than a competitor of the retail channel, and helps the supply chain win more market demand.     

Analyses of location-price game on networks with stochastic customer behavior and its heuristic algorithm

<正> In this paper,a two-stage model is developed to investigate the location strategy andthe commodity pricing strategy for a retail firm that wants to enter a spatial market with multiplecompetitive facilities,where a competitor firm is already operating as a monopoly with several outlets.Expected market shares are calculated based on the stochastic customer behavior on networks.Theauthors provide a sufficient condition for the existence of equilibrium prices in the price game for thefirst time.The existence and uniqueness of the pure strategy Nash equilibrium price with a specifiedutility function are proved in the subgame.A metaheuristic based on tabu search is proposed tosearch the optimal location-price solution of the model.In addition,the authors provide two numericalexamples to illustrate how to obtain the optimal solution and conduct sensitivity analysis.The analysisshows that the best location decision is robust for the follower firm,price game is more intense whenincomes of consumers are lower or there are more substitution products,and neither chain retail gainsfrom the price competition.     

Optimal policy with a total order quantity commitment contract in the presence of a spot market

In this paper,the optimal policy is considered when the buyer faces two supply sources:one is the contract supplier from which the buyer orders over a specific contract period(say,a year) at a pre-agreed price,and the other is the spot market.However,when ordering from the contract supplier,the buyer must fulfill a pre-determined total order quantity,or the so-called definite total order quantity commitment,over the whole contract period.In other words,the commitment secures the buyer a fixed price but obliges him/her a total order quantity over the contract period.Although the spot market gives the buyer more flexibility in terms of order quantities,its prices are volatile.Such a combination of contract and spot procurements is often observed in practice.Within the contract period,there are multiple sub-periods,during each of which the buyer reviews the inventory,issues an individual order,and uses the on-hand inventory to meet the random demand.Thus,in each(ordering) period,the buyer will weigh between the current known spot price(by procuring from the spot market) and a lower future price(by waiting while consuming the remaining commitment).An optimal dual ordering policy is characterized for each period,depending on the on-hand inventory level,the spot price,and the remaining commitment quantity.The optimal policy in each period is also shown to be independent of the contract price.Through a numerical study,the inventory cost is demonstrated to be(1) insensitive to the contract price when the total commitment quantity is lower than the total expected demand over the contract period and(2) non-increasing in the variability of spot prices.     

Stochastic comparisons in a price-quantity setting firm with uncertain demand and emergency procurement

We consider a newsvendor problem with price-dependent demand, in either additive or multiplicative format. The newsvendor has two modes of purchasing： regular ordering at the beginning of the selling season and emergency ordering （if the realized demand exceeds the initial order quantity） at the end of the selling season. By stochastic comparisons, we systematically investigate the effects of demand magnitude and demand randomness on pricing and ordering quantity decisions as well as expected profit of the newsvendor, under both usual stochastic order （first order stochastic dominance） and convex order （less variable）. Our key findings include： （i） in contrary to the case where price is exogenous, a stochastically larger demand shock may even lead to a lower order quantity; （ii） a stochastically larger demand shock leads to a higher price for the additive demand case, but may lead to a lower price for the multiplicative demand case; （iii） a stochastically larger demand shock leads to a higher expected profit for both demand models; （iv） in general, a less variable demand leads to a higher expected profit for both demand models; and furthermore, a less variable demand shock has no effect on price for the additive demand model, but leads to a higher price for the multiplicative demand model. The implications of all these findings for pricing and order quantity are discussed in detail.     

基于差价补偿策略的集装箱班轮运输定价模型

针对集装箱班轮运输定价问题,构建差价补偿策略下班轮运输的定价模型,研究差价补偿策略下托运人订舱行为和承运人定价决策,分析市场需求波动与承运人定价、差价补偿系数、承运人收益的内在关系,以及承运人定价对托运人订舱量的影响,并通过数值分析进行验证.结果表明:随着市场需求波动的增大,承运人最优定价与最大收益降低,而差价补偿系数增大;且托运人订舱量随着承运人定价的增大而减少.承运人采用差价补偿策略时,市场需求波动存在一个上限值,如果需求波动小于该值,则承运人采用差价补偿策略有利于其提高收益.     

Analysis on the Mutation and Time-Varying Characteristics of Coal Price System Evolution from the Perspective of Finance

Coal is essential to ensure China's energy security. The sudden or gradual change of coal price reflects the degree of disequilibrium or expected disequilibrium of coal supply and demand, which will not be conducive to energy security. Therefore, it is important to analyze the change points of coal price and explore the reason of the price fluctuation. This paper analyses the coal price from January2008 to June 2019 as the perspective of the financial market. Firstly, the PPM-DBSCAN model is used to identify the mutation point of coal price fluctuation. Secondly, path analysis is used to extract the core driving factors that affect coal price. Thirdly, the authors construct a time-varying and time-lag effect analysis model for structural changes of coal price based on the TVP-VAR model. The results show that there are 11 mutation points of coal price fluctuation. Financial market factors, coal supply and demand and alternative factors are the reasons of coal price mutation. The authors find that the imbalance of coal supply and demand in traditional view cannot fully explain the fluctuation of coal price. The impact of the financial market and non-thermal power generation have more influence on the coal price.     

随机性需求下一类分销系统的协调问题及仿真

在随机性需求条件下 ,研究一类包括单一制造商与多零售商 (设为 N个 ,N≥ 2 )的分销系统的协调问题 ,各自以利润最大为目标 ,最终确定最优的批发价格 w和订货量 Qi,i=1 ,2 ,… ,N,同时给出计算的方法 ,并通过仿真分析当市场情况发生变化时 ,供应链发生何种变化 ,如何调整 w和 Qi     

需求不确定性对最小化成本和最大化利润报童问题的影响

运用应用概率中的随机占优和可变序研究需求不确定性对两类报童问题的影响,一类是经典的最小化成本报童问题,另一类是带有二次订货策略的最大化利润报童问题. 得到对应于两类报童问题的最优成本（最优利润）关于缺货惩罚费用（二次订货费用）的单调性,并从最优化和随机比较两个方面分析两类模型的等价性. 针对最大化利润报童问题,给出在分散序意义下比较系统最优利润的充分条件,并证明当二次订货费用小于或等于零售价格时,随机大需求导致较高的最优利润,但当二次订货费用大于零售价格时此结论不一定成立. 证明对任意二次订货费用,在二阶随机占优意义下系统最优利润随需求可变性增加而减小. 进一步,证明存在一类需求分布,当需求均值相等且二次订货费用大于某一固定值时,系统最优利润随需求可变性的增加而增加. 对最小化成本报童问题给出类似的结果. 数值例子验证了得到的研究结果.     

THE IMPACTS OF PRICING SCHEMES ON DECENTRALIZED ASSEMBLY SYSTEMS

We study an assembly system where one assembler produces a final product to satisfy the price sensitive and uncertain demands. One unit of final product needs inputs from n complementary components each provided from a distinct supplier. The assembler orders from the suppliers and their relationships are governed by price-only contracts. The assembler practices two alternative pricing schemes： a fixed pricing scheme by which she fixes a retail price in all market situations, and a responsive pricing scheme by which she adjusts retail prices after observing actual demand curves. We find that, when the assembler practices the two pricing schemes, the suppliers charge the same wholesale prices, channel profit is allocated among the firms according to the same proportions, and the relative performances of the system under decentralized decision makings with respect to those under centralized decision makings are the same. Furthermore, responsive pricing improves the assembler＇s absolute performance, and the gains pass over to the suppliers in terms of higher profits and to the customers in terms of enhanced product availability and lowered market price.     

需求预测信息更新条件下供应链的三阶段期权协调机制

考虑需求信息更新条件下的供应链期权协调机制, 研究三阶段生产和订购模型: 零售商在第一阶段发出固定订单并购买期权; 然后在第一和第二阶段之间更新需求信息, 并在第二阶段对固定订购量和期权购买量分别进行调整; 第三阶段满足市场需求, 通过执行期权并在必要时启动紧急订购满足前两阶段固定订货不足的部分. 协调机制的参数包含两个期权购买价格、一个期权执行价格和紧急订购对应的批发价, 且后两者均是期权购买价格的二元隐函数. 算例分析结果表明: 供应链及其成员的利润都得到帕累托改进; 两个期权购买价格及其比例关系对零售商订购决策和系统利润增量分配有着敏感影响; 期权价格在第一阶段的下降和第二阶段的上升均会为制造商带来投机动力, 争取谈判优势是零售商的理性选择.