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.     

Impact of Price Postponement on Capacity and Flexibility Investment Decisions

Investments in dedicated and flexible capacity have traditionally been based on demand forecasts obtained under the assumption of a predetermined product price. However, the impact on revenue of poor capacity and flexibility decisions can be mitigated by appropriately changing prices. While investment decisions need to be made years before demand is realized, pricing decisions can easily be postponed until product launch, when more accurate demand information is available. We study the effect of this price decision delay on the optimal investments on dedicated and flexible capacity. Computational experiments show that considering price postponement at the planning stage leads to a large reduction in capacity investments, especially in the more expensive flexible capacity, and a significant increase in profits. Its impact depends on demand correlation, elasticity and diversion, ratio of fixed to variable capacity costs, and uncertainty remaining at the times the pricing and production decisions are made.     

制造企业服务化路径选择研究

服务化已经成为制造企业获取和保持竞争优势的重要途径，其本质是企业价值链的延伸，既包括投入服务化，又包括产出服务化。在实施服务化战略时，制造企业可以选择将投入、产出服务功能内部化或外部化，即自营或外包。从产品层面构建理论模型，比较研究制造企业的四种服务化路径：（1）外包投入服务和产出服务；（2）外包投入服务，自营产出服务；（3）自营投入服务，外包产出服务；（4）自营投入服务和产出服务。首先，通过分析需求质量弹性和质量成本系数、制造企业产品及服务的质量和价格、生产性服务企业服务的质量和价格以及制造企业与生产性服务企业的市场基础等模型变量，得到制造企业在每种服务化路径下的最大化利润。其次，通过比较每种路径下的最大化利润，得到路径选择的临界条件。最后，通过数值实验和算例分析，验证了模型的有效性和实用性。研究结果表明，何种路径成为更优的选择取决于制造企业的自身条件和所面临的市场环境。总体而言，在质量成本系数足够大于需求质量弹性的前提下，生产性服务企业所提供投入服务或产出服务的市场基础越大，将该种服务外部化的预期利润越高。研究结果将为制造企业的服务化路径选择提供理论依据和解决方案。     

从中国农民医疗保健支出行为看农村医疗保健融资机制的选择

我们是在一个市场环境中考察财政融资或医疗保险可能会对农民的医疗开支产生什么效应,这些效应又在何种程度上会影响财政平衡?本人绕过了关于农民对医疗服务与药品需求量的度量,证明了在一定条件下,我们可以根据消费者的货币支出量、支出比率、价格与收入,来估算需求的自价格弹性。我们发现,中国财政对卫生的公共支出占全国卫生总支出的比率,已到了世界最低行列！中国占人口80％的农民在非公共卫生支出中只占不到20％！中国西部(11省、区)的农民医疗卫生负担与东、中部农民相比,呈累退趋势:越穷负担越重！中国农村居民对医疗价格与药品价格的弹性为负,卫生支出对收入的弹性为正,因此,引入保险机制与财政补贴会产生医药开支的膨胀,膨胀系数为0.863！中国西部农民对医疗服务价格的需求弹性显著为负,且小于-1;中国东部农民对药品价格的需求弹性显著为负。在补助医还是补助药上,西部与东部应该采用不同的融资方式。计量结果表明,西部农民的看病、买药决策显著取决于收入水平;而在东部地区,这一关系不显著。财政支出在东部已经起到了降低农民医疗负担的功效;而在西部农村,则尚无这方面效果。     

FDI技术溢出与中国企业创新产出

采用2004年至2008年中国30个省市自治区的面板数据,运用二级三要素CES生产函数分析FDI对中国企业技术创新溢出效应的可行性,揭示FDI、R&D经费投入和R&D人力资本投入3个投入要素之间以及与企业创新产出之间的复杂关系。研究结果表明,要素间的固定替代弹性系数不等于1,因而证明了运用CES生产函数的可行性;FDI对中国企业创新产出产生正面的溢出效应,FDI流入量每增加1%,能使专利申请授权数增加0.18%;但是通过计算1990年至2008年FDI对企业创新的产出弹性发现,该产出弹性并没有随FDI引进量的增加而增加,反而有所下降;R&D经费投入和R&D人力资本投入是影响企业对FDI知识溢出吸收能力的关键因素,中国R&D人力资本的缺乏抑制了企业吸收FDI知识溢出的能力。     

随机产出与需求下农产品供应链协调的收益共享合同研究

生鲜农产品生产受季节性和天气等影响,投入一定农资后产出呈随机分布。本文考虑产出和需求扰动服从均匀分布情形下,单个生产商和零售商的供应链协调问题。在收益共享合同模式下,生产商决定农资投入数(e)并将单一产品以低于生产成本的价格(ω)全部出售给零售商,零售商制定销售价格(p)进行销售并支付约定比例(1-Ф)的收益补偿生产商。在分析供应链协调的条件后,说明了合同参数ω与Ф的关系和Ф设定范围。研究结果表明,收益共享合同能有效地协调供应链,且协调的p和e与需求价格弹性有关;并且Ф取值范围随影响产出的随机变量的期望值变大而增大。最后以数值算例说明了分析结果的正确性。     

The Effects of a Baby Boom on Stock Prices and Capital Accumulation in the Presence of Social Security

Is the stock market boom a result of the baby boom? This paper develops an overlapping generations model in which a baby boom is modeled as a high realization of a random birth rate, and the price of capital is determined endogenously by a convex cost of adjustment. A baby boom increases national saving and investment and thus causes an increase in the price of capital. The price of capital is mean–reverting so the initial increase in the price of capital is followed by a decrease. Social Security can potentially affect national saving and investment, though in the long run, it does not affect the price of capital.     

竞争环境下新创企业产量柔性技术战略决策研究

考虑新创企业与成熟企业相互竞争,重点研究竞争环境下,两企业的产量柔性技术选择及产能投资决策。首先分析了四种不同策略组合下两企业的最优产能决策、新创企业的最大生存概率以及成熟企业的最大利润;然后用传统博弈论的方法得出了二者的竞争均衡,并分析影响两企业产量柔性战略决策的因素;最后用数值实验进行验证。研究结果表明：在竞争中,新创企业更加关注成本因素,倾向于选择成本较小的无柔性技术;成熟企业对市场需求的波动更为敏感,当市场需求波动较大时,选择产量柔性技术能提高其收益;当产量柔性技术单位产量调整成本较大时,选择无柔性技术对两企业更为有利。     

Sentiments and Aggregate Demand Fluctuations

We formalize the Keynesian insight that aggregate demand driven by sentiments can generate output fluctuations under rational expectations. When production decisions must be made under imperfect information about demand, optimal decisions based on sentiments can generate stochastic self‐fulfilling rational expectations equilibria in standard economies without persistent informational frictions, externalities, nonconvexities, or strategic complementarities in production. The models we consider are deliberately simple, but could serve as benchmarks for more complicated equilibrium models with additional features.     

A systems simulation model of the Kenyan economy

This paper describes a systems simulation model of the national economy of Kenya. The model contains an input/output production component linked to a consumption component, disaggregated into nine income classes. Capital formation and government are integrated into the model as interactive elements. The model is demand driven and thus growth rates in the productive sectors are generated endogenously as a function of demand. The model has been used by the Kenyan Ministry of Finance and Economic Planning for forecasting and policy evaluation problems. A contributory factor in the successful implementation of the model is its ability to supply detailed quantitative forecasts which, in a developing country, are not readily available from routine sources. In addition, the model deals explicitly with income distribution and inflation consequences which are issues of current concern to local development planners.     

知识型企业内部创新网络创新激励策略研究

基于复杂技术创新的联合性特征,建立了知识型企业内部创新网络创新合作博弈模型,模型求解和数值仿真结果表明,节点创新投入策略具有随产出弹性的增加而增加、随其他节点创新能力水平的提升而增加以及随自身创新能力水平的提高呈先增加后减少等特征。在此基础上,分析得出对知识型企业内部创新网络进行创新激励的若干策略建议。     

A shelf-space optimization model when demand is stochastic and space-elastic

The more customer demand is impulse-driven, the more it is space-dependent and the more it is subject to variation. We investigate the corresponding problem of retail shelf-space planning when demand is stochastic and sensitive to the number and position of facings. We develop a model to maximize a retailer׳s profit by selecting the number of facings and their shelf position under the assumption of limited space. The model is particularly applicable to promotional or temporary products.We develop the first optimization model and solution approach that takes stochastic demand into account, since the current literature applies deterministic models for shelf-space planning. By the means of an innovative modeling approach for the case with space- and positioning effects and the conversion of our problem into a mixed-integer problem, we obtain optimal results within very short run times for large-scale instances relevant in practice. Furthermore, we develop a solution approach to account for cross-space elasticity, and solve it using an own heuristic, which efficiently yields near-optimal results. We demonstrate that correctly considering space elasticity and demand variation is essential. The corresponding impacts on profits and solution structures become even more significant when space elasticity and stochastic demand interact, resulting in up to 5% higher profits and up to 80% differences in solution structures, if both effects are correctly accounted for. We develop an efficient modeling approach, compare the model results with approaches applied in practice and derive rules-of-thumb for planners.     

随机需求环境下联产品系统价格与产量决策研究

基于固定比例生产技术和多产品随机需求的情形,研究了联产品制造商的两阶段产量和价格联合优化模型。通过反向倒推的优化求解,得到了联产品制造商的最优产量和价格决策以及变化规律。同时研究了需求服从均匀分布时,需求波动对均衡的影响。研究结果表明,在订货成本较低和一种产品的需求波动性较大时,当另外一种产品的波动增大,则该产品的最优订货量增大,同时价格下降。借助数值仿真,分析了价格敏感度和产出比例对最优决策和利润的影响。结果表明,在给定一种产品的价格敏感度时,另外一种的价格敏感度越大,那么该产品的价格就越低,制造商的订货量就下降。当一种产品的产出比例固定时,另一种产品的产出比例上升时,则该产品的价格下降,制造商的订货量下降,总利润上升。     

Employment Illusion,Variable Costs of Migration and Labour Mobility

Why is internal migration in Italy so modest despite the presence of high differentials in employment rates? The paper proposes two different explanations. First, since migration is an investment with non-recoverable costs, it depends not only on the current differential between incomes in the two regions but also on expectations about the same differential in the future. Therefore, the existence of a relatively low differential between adult employment rates is a strong disincentive against migration in the presence of static expectations. The second explanation of the phenomenon is based on the role played by the network costs of migration. If they are important, it is evident that the changes and productive reallocations that have characterized the Italian economy in recent years are important in explaining the decline of migration.     

MANAGING CREDIT BUBBLES

We study a dynamic economy where credit is limited by insufficient collateral and, as a result, investment and output are too low. In this environment, changes in investor sentiment or market expectations can give rise to credit bubbles, that is, expansions in credit that are backed not by expectations of future profits (i.e., fundamental collateral), but instead by expectations of future credit (i.e., bubbly collateral). Credit bubbles raise the availability of credit for entrepreneurs: this is the crowding‐in effect. However, entrepreneurs must also use some of this credit to cancel past credit: this is the crowding‐out effect. There is an “optimal” bubble size that trades off these two effects and maximizes long‐run output and consumption. The equilibrium bubble size depends on investor sentiment, however, and it typically does not coincide with the “optimal” bubble size. This provides a new rationale for macroprudential policy. A credit management agency (CMA) can replicate the “optimal” bubble by taxing credit when the equilibrium bubble is too high and subsidizing credit when the equilibrium bubble is too low. This leaning‐against‐the‐wind policy maximizes output and consumption. Moreover, the same conditions that make this policy desirable guarantee that a CMA has the resources to implement it.     

Coordinating Service‐Sensitive Demand and Capacity by Adaptive Decision Making: An Application of Case‐Based Decision Theory*

The subject of this article is the simultaneous choice of product price and manufacturing capacity if demand is stochastic and service‐level sensitive. In this setting, capacity as well as price have an impact on demand because several aspects of service level depend on capacity. For example, delivery time will be reduced if capacity is increased given a constant demand rate. We illustrate the relationship between service level, capacity, and demand reaction by a stylized application problem from the after‐sales services industry. The reaction of customers to variations in service level and price is represented by a kinked price‐demand‐rate function. We first derive the optimal price‐capacity combination for the resulting decision problem under full information. Subsequently, we focus on a decision maker (DM) who lacks complete knowledge of the demand function. Hence the DM is unable to anticipate the service level and consequently cannot identify the optimal solution. However, the DM will acquire additional information during the sales process and use it in subsequent revisions of the price‐capacity decision. Thus, this decision making is adaptive and based on experience. In contrast to the literature, which assumes certain repetitive procedures somewhat ad hoc, we develop an adaptive decision process based on case‐based decision theory (CBDT) for the price‐capacity problem. Finally, we show that a CBDT DM in our setting eventually finds the optimal solution, if the DM sets the price based on absorption costs and adequately adjusts the capacity with respect to the observed demand.     

Nonhomotheticity and Bilateral Trade: Evidence and a Quantitative Explanation

The standard gravity model predicts that trade flows increase in proportion to importer and exporter total income, regardless of how income is divided into income per capita and population. Bilateral trade data, however, show that trade grows strongly with income per capita and is largely unresponsive to population. I develop a general equilibrium Ricardian model of trade that allows the elasticity of trade with respect to income per capita and with respect to population to diverge. Goods are of various types, which differ in their income elasticity of demand and in the extent to which there is heterogeneity in their production technologies. I estimate the model using bilateral trade data of 162 countries and compare it to a special case that delivers the gravity equation. The general model improves the restricted model's predictions regarding variations in trade due to size and income. I experiment with counterfactuals. A positive technology shock in China makes poor and rich countries better off and middle‐income countries worse off.     

AN ANALYSIS OF THE DYNAMIC THEORY OF THE MULTI—PRODUCT FIRM USING THE CALCULUS OF VARIATIONS

The purpose of this paper is to present the theory of the multi-product firm in situations where the revenue function depends not only on the rate of output but also on changes in the rate of output, and, similarly, where the cost function depends on changes in the rate of factor utilization as well as the rate of their utilization. Since the analysis will utilize the calculus of variations, a general introduction to this technique is also presented. The model analyzed assumes perfect foresight and knowledge concerning the revenue, cost, and production functions, and the calculus of variations is used to derive the conditions for an extremum. The first section presents the mathematical model and the model of the firm, and the optimality conditions are discussed in the second section.     

Operational Hedging and Diversification under Correlated Supply and Demand Uncertainty

When facing supply uncertainty caused by exogenous factors such as adverse weather conditions, firms diversify their supply sources following the wisdom of “not holding all eggs in one basket.” We study a firm that decides on investment and production levels of two unreliable but substitutable resources. Applying real options thinking, production decisions account for actual supply capabilities, whereas investment decisions are made in advance. To model triangular supply and demand correlations, we adapt the concepts of random capacity and stochastic proportional yield while using concordant ordered random variables. Optimal profit decreases monotonically in supply correlation and increases monotonically in supply–demand correlation. Optimal resource selection, however, depends on the trivariate interplay of supply and demand and responds non‐monotonically to changing correlations. Moreover, supply hedges (i.e., excess capacity at alternative sources) can be optimal even if supply resources are perfectly positively correlated. To accommodate changing degrees of correlation, the firm adjusts the lower margin capacities under random capacity; but under stochastic proportional production capability, it uses either low‐ or high‐margin capacities to create tailored “scale hedges” (i.e., excess capacity at one source which can partially substitute for diversification).     

Rationing Capacity Between Two Product Classes*

In this paper, we study the capacity allocation problem faced by make-to-order manufacturing firms encountering expected total demand in excess of available capacity. Specifically, we focus on firms' manufacturing short-life-cycle or seasonal products such as high fashion apparel. Using a decision-theory-based approach, we develop a capacity allocation policy that allows such firms to discriminate between two classes of products (one yielding a higher profit contribution per unit of capacity allocated to it than the other), resulting in selective rejection of orders for the class with the lower unit contribution. The effectiveness of capacity rationing is investigated under a wide array of conditions characterized by variations in factors such as the ratio of unit profit contributions of the two product classes, the ratio of total available capacity to expected total demand, the ratio of expected demands between the two classes, and the variability in demand for each product class. The results indicate that capacity rationing is very effective in increasing the total profit, and could therefore serve as a valuable decision tool for managers in such firms.