供应链风险管理的两个优化模型

按照风险来源,一般可将供应链风险分为需求、供应、经营、环境、制度、信息6种,本文分析了风险对供应链影响的广度和深度,按照其具体表现形式重新分为3种:偏差风险、中断风险和灾难性风险。在此基础上,建立了两个风险优化模型:一是在Markowitz模型基础上的以成本偏差最小化为目标的二次优化决策模型;二是以信用风险模型为基础、以供应赤字最小为目标的决策模型。通过模拟数据进行求解,为供应链的风险管理者提供了两种可行的选择方法。     

Means-Testing the Child Benefit

Improving the distributional impact of transfers may be costly if it reduces labor supply. In this paper we show how effects of changes in the design of the child benefit program can be examined by employing information from behavioral and non-behavioral simulations on micro data. The direct distributional effects are assessed by tax-benefit model calculations, while female labor supply responses to alternative child benefit schemes are simulated under the assumption that choices are discrete. Distributional effects after labor supply responses are also shown. The study confirms that greater targeting of the child benefit is traded against reductions in female labor supply.     

Channel competition and coordination of a dual-channel supply chain with demand and cost disruptions

The impacts of simultaneous disruption of demand and cost on pricing, production and coordination of a dual-channel supply chain with one manufacturer and one retailer are examined. First, coordination of the dual-channel supply chain without disruption is proposed, by using a revenue sharing contract. Furthermore, the effects of simultaneous disruption of demand and cost on pricing, production and profit are examined from the perspective of partners and the whole supply chain. Optimal prices and quantum of production in the event of disruptions occurring are derived. Suitable changes and improvements in revenue sharing contracts can help coordinate the dual-channel supply chain with disruptions. Finally, the proposed models are further analysed through numerical examples.     

On selecting a measure of labour activity: evidence from registered nurses, 1981 and 1989

The purpose of this paper is to demonstrate the effects of the selection of measures of labour activity on the conclusions that are derived from the analysis of individual labour supply. The results of the analysis using three commonly specified single measures (Annual Hours Worked, Hours Worked per Week, and Weeks Worked per Year) as the dependent variable in TOBIT equations are compared with those obtained using a PROBIT-2SLS in which the individual labour supply is measured by Hours Worked per Week and Weeks Worked per Year. The RHS variables are those that are used in earlier individual labour supply studies and are the same in all of the models analysed. Among the findings are (1) wage rate effects that are quite strong in single equation models and disappear when a multi-equation approach is used, (2) the effects of children on labour supply is more complex than in indicated in single equation results and (3) duration dependence is much stronger than indicated results using a single measure of individual labour supply. These results suggest that using a single measure of labour supply will lead to inappropriate conclusions as to the effects of such variables as wage rates, number and ages of children, spouse's employment state, and income from other sources on individual labour supply.     

Fertility and labor supply: evidence from the One-Child Policy in China

This study provides new evidence on on the causal effect of fertility on maternal labor supply in rural China, using the fact that in some parts of rural China couples are allowed to have a second child if their firstborn is female. Estimates show that a second child reduces maternal labor force participation by 4.6 percentage points, labor supply intensity (hours worked conditional on employment) by 1.4 h per week and monthly income by 54.5 Chinese Yuan (18.7 percent). Further, the labor supply of mothers whose husbands are rural-to-urban migrants is the most sensitive to having an additional child, likely because they have more difficulty balancing farming and childcare. Conversely, labor supply is not reduced by fertility for mothers living in three-generation families, most likely because grandparents can provide both time and money to help with childcare.     

需求和供给方视角下远程医疗采用元分析

远程医疗的需求方和供给方均是远程医疗的使用者,但需求方的决策属于选择性创新决策,而供给方的决策属于可能性创新决策.为探索这两种创新决策采用影响因素的差异性,本文从需求方和供给方共有因素、需求方特有因素、供给方特有因素3个角度构建了远程医疗采用概念模型,并收集了21项研究进行元分析.结果表明:①需求方独有的影响因素有:感知易用性、社会影响、便利条件、感知收益、感知障碍、行为线索;供给方独有的影响因素有:高层管理支持;②态度、感知有用性、绩效期望、努力期望为需求方和供给方共有的影响因素;③相比远程医疗的供给方,绩效期望、努力期望、社会影响和便利条件对需求方的影响更大.     

Business cycle fluctuations and the life cycle: How important is on-the-job skill accumulation?

We study the effects of on-the-job skill accumulation on average hours worked by age and the volatility of hours over the life cycle in a calibrated general equilibrium model. Two forms of skill accumulation are considered: learning by doing and on-the-job training. In our economy with learning by doing, individuals supply more labor early in the life cycle and less as they approach retirement than they do in an economy without this feature. The impact of this feature on the volatility of hours over the life cycle depends on the value of the intertemporal elasticity of labor supply. When individuals accumulate skills by on-the-job training, there are only weak effects on both the steady-state labor supply and its volatility over the life cycle.     

Labour-supply impacts of effective welfare programme parameters: a reanalysis

We quantify the impact of effective welfare programme parameters on the labour supply of single female household heads – the primary group of welfare recipients in the USA. Our panel of data is derived from the US Census Bureau's Current Population Survey for the years 1979 to 1990 inclusive. Behavioural impacts from a range of economic variables are consistent in sign with predictions made by economic theory. We find that effective welfare gurantee levels and the effective tax rate on earned income both significantly decrease labour supply. The marginal effects of these welfare programme parameters are economically small: a US$1000 increase in the expected welfare guarantee level reduces annual labour supply by about 36 hours; a 10 percentage point increase in the effective tax rate on earned income reduces annual labour supply by about 7.5 hours.     

基于供求关系的生猪契约定价博弈分析

从生猪产业链上养殖主体与工贸企业之间的供求关系出发,基于供求关系的情景差异,以生猪契约价格为研究对象,运用商品供求理论和博弈论方法,分析养殖主体和工贸企业之间围绕生猪购销价格的博弈过程,得到了信息获取与处理能力影响契约价格形成、养殖主体的决策心理规律、工贸企业价格降幅方案和谈判成功率、专业化合作组织有助于增强养殖主体的价格订单谈判力等结论,为我国生猪产业健康发展提供了理论依据和方法支撑。     

Disentangling supply and demand shifts: the impacts on world salmon price

To understand price changes, one must determine the relative impact of supply and demand shifts on price. Conditional on predetermined supply and demand elasticities, we retrieve yearly shifts in regional supply and demand. The relative impact on price from each supply and demand shift is determined through an equilibrium displacement model (EDM). This procedure is applied on a yearly basis for the world salmon market in the period 2002 to 2011. The results indicate a large variation in demand and supply growth both over time and between regions. While average annual price impacts from supply or demand shifts from most regions are not statistically significant, price impacts from supply or demand shifts for specific periods are detected in all but one region. This indicates that the use of smooth trend indicators is likely to be inappropriate for measuring supply and demand shifts and their impacts on price. The procedure presented in this article can be a useful instrument for determining the relative impacts of supply and demand shifts on price in any market with unstable price behaviour.     

A model of commodity prices after Sir Arthur Lewis

We develop an idea from Arthur Lewis' paper on unlimited supplies of labor to model the long-run behavior of the prices of primary commodity produced by poor countries. Commodity supply is assumed infinitely elastic in the long run, and the rate of growth of supply responds to the excess of the current price over the long-run supply price. Demand is linked to the level of world income and to the price of the commodity, so that price is stationary around its supply price, and commodity supply and world income are cointegrated. The model is fitted to long-run historical data.     

Is there Causal Relationship between Money Supply Growth and Inflation in China? Evidence from Quantity Theory of Money

This study examines the causal relationship between Chinese money supply growth and inflation, using the bootstrap Granger full‐sample causality test and sub‐sample rolling‐window estimation test to determine whether such a relationship in China supports the quantity theory of money. The result indicates that there is a unidirectional relationship from inflation to money supply growth. However, considering structural changes in two series, we find that short‐run relationships using full‐sample data are unstable, which suggests that full‐sample causality tests cannot be relied upon. Then, we use a time‐varying rolling‐window approach to revisit the dynamic causal relationship, and the results show that money supply growth has both positive and negative impacts on inflation in several sub‐periods, and in turn, inflation has the same effects on money supply growth for China. These findings are basically consistent with the modern quantity theory of money from the perspective of money supply and price level. When money supply growth does not outweigh output growth, inflation should not be curbed only by decreasing money supply. It notes that a stable money supply growth is critical to price level stability and economic development in China.     

基于价值链分析的随机环境下的供应链优化

本文分析了供应链与价值链的关系,指出从系统整体考虑供应链的协调才能使其得到优化,针对供应链中存在的随机因素,按照价值链分析思想,分别建立随机环境下的制造型供应链协调与优化模型和流程型供应链协调与优化模型。通过数值计算,分析随机性和决策者选择的置信水平对供应链资源最优配置结构的影响。     

集群供应链环境治理与政府监管博弈分析

笔者研究了集群供应链跨链合作与政府监管的博弈模型,通过在不同单链式供应链在不同策略下各自的成本和收益基础上,运用博弈理论研究了政府环境管制与集群供应链跨链合作的关系。研究结果表明:原材料的采购价格和单位副产品的排污收费是集群供应链实施跨链合作的驱动力;再利用固定成本以及废弃物的产出规模是集群供应链跨链合作能否实施的先决条件;政府的法制监管成本、环境管制失职招致的信誉损失、政府对核心企业副产品排放而进行的罚款直接影响到博弈结果。     

Money disillusion and stagflation

In the conventional income-expenditure model with rigid wages, the aggregate supply curve is upward sloping. Increases in demand therefore imply increases in real output and employment. We demonstrate here that this conclusion depends on the form of money illusion implied by the rigid wage assumption. If we assume instead that labor supply is more sensitive to price increases than to wage increases, the aggregate supply curve is negatively sloped, and the conventional policy multipliers are thereby reversed. In the second section, we show that this result also follows if labor supply depends on the expected real wage.     

Shifting Taxes from Labor to Consumption: More Employment and more Inequality?

This paper investigates the effect of shifting taxes from labor income to consumption on labor supply and the distribution of income in Germany. We simulate stepwise increases in the value‐added tax (VAT) rate, which are compensated by revenue‐neutral reductions in income‐related taxes. We differentiate between the personal income tax (PIT) and social security contributions (SSC). Based on a dual data base and a microsimulation model of household labor supply behavior, we find a regressive impact of such a tax shift in the short run. When accounting for labor supply adjustments, the adverse distributional impact persists for PIT reductions, while the overall effects on inequality and progressivity become lower when payroll taxes are reduced. This is partly due to increases in aggregate labor supply, resulting from higher work incentives.     

“十一五”以来各省份环保投资供求水平及其空间均衡性分析

基于回归模型分别构建地方环保投资供给能力和需求水平两个评价指标,并计算了我国环保投资供给能力、需求水平及供求水平比的基尼系数,探究了东、中、西部地区环保投资供求水平的空间差异。结果表明,我国环保投资供给能力和需求水平在空间上较为匹配,均呈现东部地区最强、中部地区次之、西部地区最弱的格局,其中,环保投资供给能力在空间分布上均衡性相对较差,基尼系数在0.4左右浮动。我国环保投资供给和需求的变化在时间上相对不同步,"十一五"期间,环保投资供给能力上升速度高于环保投资需求水平;"十二五"期间,环保投资供给能力的上升速度明显跟不上需求水平;"十三五"期间,仅南方部分省份的环保投资供给能力高于环保投资需求水平。     

中国当前农村公共文化设施供给:问题识别及原因分析——基于河南嵩县的实证调查

城乡统筹战略的提出标志着我国农村公共物品供给发展进入了一个新的阶段。作为公共物品的一部分,农村文化供给也明显增加。但是总量的增加并不意味着结构的改善和效率的提升。本文利用河南省嵩县调查数据,重点对我国新形势下的农村公共文化设施供需结构和供给效率进行了研究。结果表明,目前农村公共文化供给存在较为明显的供需结构失衡和供给无效等问题。造成结构失衡的主要原因在于供给的自上而下,供给无效则与干群关系恶化、农民需求表达、农民自身特点存在着密切相关的关系。     

基于可靠性的供应链冗余设计及成员重要度分析

首先,根据供应链中6类生产依赖关系引出生产相关度概念,提出了基于最小路集的供应链可靠性算法;然后,将冗余设计和成员重要度分析引入供应链可靠性设计;最后,设计了6种带冗余的供应链结构,进行了可靠度计算,并对供应链成员企业进行了概率重要度和关键重要度分析。     

Fertility,household structure,and parental labor supply: Evidence from China

This study examines the effects of fertility on household structure and parental labor supply in China. To solve the endogeneity problem, we use a unique survey on households with twin children and a comparison group of non-twin households. The ordinary least squares estimates show a negative correlation between fertility and parental labor supply in rural China. Using twinning as a natural experiment, we do not find evidence on the negative effects of fertility on parental labor supply. By contrast, we find that the twinning-induced increase in fertility significantly enhances the coresidence of grandparents in rural China. We suggest that the negative effects of fertility on parental labor supply are mitigated by the childcare provided by grandparents in rural China. We also find that fertility does not induce coresidence of grandparents in urban China. Our results have important implications for population and public childcare policies.