Time-inconsistent preferences and time-inconsistent policies

Social security is commonly viewed as a commitment device for hyperbolic consumers. We argue that such common intuition is not consistent with formal economic theory. In a model where the government can choose either time-consistent or time-inconsistent policies to govern its social security arrangement and credit markets are complete, only a time-inconsistent policy achieves true commitment by hyperbolic consumers. This rules out a traditional social security program as a commitment device.     

研究型大学、教师行为与科研激励合同：基于委托代理关系的分析

作为研究型大学的主体,教师的行为受到科研激励机制的影响。大学通过激励机制来规范教师的行为,教师则通过自身的努力获取收益和规避风险。文章基于大学和教师之间的委托代理关系,在不对称信息条件下探讨大学和教师应如何订立科研激励合同。结果表明：当不考虑监控成本时,在最优显性激励合同中加入外控变量可以使得风险成本和激励成本下降,从而降低代理成本。在大学和教师的长期合作中,则必须充分发挥隐性激励合同的作用。     

基于委托代理的区域高校协作激励机制设计

区域化的经济发展为区域高等院校协作提供了现实需求,加强高等教育区域协作已经成为必要,而如何设计有效的激励机制是协作成功与否的关键。本文通过建立地方政府和高校之间的协作机制模型,研究了我国区域高等院校协作中的委托代理问题和激励机制设计问题,并通过对模型的优化得到相应的激励机制。     

基于委托-代理模型的二次供水监管与激励研究

供水管理部门与物业管理公司在二次供水过程中有着明显的委托-代理关系,通过对二者的委托-代理关系进行模型构建与分析,得出结论认为物业管理公司的努力程度除受自身的经营管理能力和运营成本的影响外,还需要供水管理部门依据物业管理公司的能力系数、成本系数、风险偏好以及检验费用系数、不可控的环境条件等因素,设计合理的契约合同加强对二次供水过程的监管与激励,并提出相关建议。     

The first-order approach when the cost of effort is money

We provide sufficient conditions for the first-order approach in the principal-agent problem when the agent’s utility has the nonseparable form u(y−c(a))$u(y-c\left(a\right))$ where y$y$ is the contractual payoff and c(a)$c\left(a\right)$ is the money cost of effort. We first consider a decision-maker facing prospects which cost c(a)$c\left(a\right)$ and with distributions of returns y$y$ that depend on a$a$. The decision problem is shown to be concave if the primitive of the cdf of returns is jointly convex in a$a$ and y$y$, a condition we call Concavity of the Cumulative Quantile (CCQ) and which is satisfied by many common distributions. Next we apply CCQ to the distribution of outcomes (or their likelihood-ratio transforms) in the principal-agent problem and derive restrictions on the utility function that validate the first-order approach. We also discuss another condition, log-convexity of the distribution, and show that it allows binding limited liability constraints, which CCQ does not.     

Dynamic asset allocation when bequests are luxury goods

Luxury bequests impart systematic effects of age to an investor's optimal allocation: the expected percentage allocation to equities rises throughout retirement. When bequests are luxuries the marginal utility of bequests declines more slowly than the marginal utility of consumption. This is essentially lower risk aversion. As a retiree approaches death, her expected remaining lifetime utility is increasingly composed of bequest utility, and thus generates progressively lower risk aversion. A retiree responds by increasingly favoring the higher-return risky asset. Compared to standard preferences, luxury bequests elevate a retiree's average exposure to the risky asset, but the difference is small in early retirement.     

浅谈简易收放带装置的设计及应用

带式输送机是煤矿生产必不可少的生产设备,然而随着工作面的结束,胶带的回收则是一项费力、费时的工作,此种简易的收放带装置则能通过盘车载着绞车,再用四根单体液压支柱支着顶板固定实现胶带的快速回收,不仅省时省力,避免胶带用人力回收造成的破损,而且移动方便,造价低,回收胶带成卷整齐。     

Measuring and forecasting retail trade in real time using card transactional data

We build big data retail trade indicators for Spain using high-dimensional card transaction data from one of the country’s biggest banks. The resulting indicators replicate the dynamics of the Spanish retail trade indices (RTI), regional RTIs (Spain’s autonomous regions), and RTI by retailer type (distribution classes) released by the Spanish National Statistics Institute. The new indicators not only have a higher frequency (daily data) and higher geographical and sectorial breakdown but are also shown to improve nowcasting and forecasting power for the official RTI, making them key variables to monitor consumption.     

时差式超声波流量计的应用技术

时差式超声波流量计是过程自动化仪表与装置中的重要仪表之一。文章介绍了时差式超声波流量计的工作原理、特点和应用技术,重点阐述时差式超声波流量计在实际应用中的安装及使用方法。     

时差式超声波流量计的应用技术

时差式超声波流量计是过程自动化仪表与装置中的重要仪表之一。文章介绍了时差式超声波流量计的工作原理、特点和应用技术,重点阐述时差式超声波流量计在实际应用中的安装及使用方法。     

蚁群算法解决有时间窗的车辆优化调度问题研究

有时间窗的车辆路径问题（Vehicle Routing Problem With Time Windows，VRPTW）属于NP-Hard问题，严格的时间约束使VRFTW非常复杂。应用蚁群算法（Ant Colony Algorithm,ACA）思想来解决VRPTW。对已有蚁群算法解决车辆路径优化问题（VRP）的模型进行改进，对算法中相应的转移规则和轨迹更新规则进行了重新设定，改进了算法转移策略和信息素更新策略。给出了算法的实现步骤。通过算例分析，将计算结果与遗传算法（GA）和粒子群算法（PSO）作了比较，对模型和算法的正确性、高效性、适用性进行了验证。实验结果表明，ACA可以快速、有效求得VRFTW的优化解，是求解VRFTW的一个较好方案。     

基于时间满意的应急物资运输模型与算法

根据应急抢险救灾物资需求时效性强的特点,定义了考虑时间因素和需要量满足程度的时间满意度函数,建立时间满意的多目标应急物资运输问题的数学模型。针对数学模型,设计了序贯式算法,并利用LINGO软件编制程序进行了求解。最后通过一个实例验证了数学模型的科学性和算法的有效性。