An approximate dual-self model and paradoxes of choice under risk

We derive a simplified version of the model of Fudenberg and Levine, 2006, Fudenberg and Levine, 2011 and show how this approximate model is useful in explaining choice under risk. We show that in the simple case of three outcomes, the model can generate indifference curves that “fan out” in the Marschak–Machina triangle, and thus can explain the well-known Allais and common ratio paradoxes that models such as prospect theory and regret theory are designed to capture. At the same time, our model is consistent with modern macroeconomic theory and evidence and generates predictions across a much wider set of domains than these models.     

解读《哈克贝利·费恩历险记》中的悖论与反讽——一种新批评的视角

作为马克·吐温的盛名之作,《哈克贝利·费恩历险记》历来受到中外论者的偏爱,而其叙事结构和语言特征更是学界争论的焦点。本文以克林斯·布鲁克斯的悖论、反讽理论为批评视角,探究了该部作品的叙事艺术。审视之下,不难发现,小说中蕴涵的悖论与反讽是营造整个文本的美学旨归。     

When Does Poor Governance Presage Biosecurity Risk?

Border inspection, and the challenge of deciding which of the tens of millions of consignments that arrive should be inspected, is a perennial problem for regulatory authorities. The objective of these inspections is to minimize the risk of contraband entering the country. As an example, for regulatory authorities in charge of biosecurity material, consignments of goods are classified before arrival according to their economic tariff number. This classification, perhaps along with other information, is used as a screening step to determine whether further biosecurity intervention, such as inspection, is necessary. Other information associated with consignments includes details such as the country of origin, supplier, and importer, for example. The choice of which consignments to inspect has typically been informed by historical records of intercepted material. Fortunately for regulators, interception is a rare event; however, this sparsity undermines the utility of historical records for deciding which containers to inspect. In this article, we report on an analysis that uses more detailed information to inform inspection. Using quarantine biosecurity as a case study, we create statistical profiles using generalized linear mixed models and compare different model specifications with historical information alone, demonstrating the utility of a statistical modeling approach. We also demonstrate some graphical model summaries that provide managers with insight into pathway governance.     

A Stochastic Model to Assess the Effect of Meat Inspection Practices on the Contamination of the Pig Carcasses

The objective of meat inspection is to promote animal and public health by preventing, detecting, and controlling hazards originating from animals. With the improvements of sanitary level in pig herds, the hazards profile has shifted and the inspection procedures no longer target major foodborne pathogens (i.e., not risk based). Additionally, carcass manipulations performed when searching for macroscopic lesions can lead to cross‐contamination. We therefore developed a stochastic model to quantitatively describe cross‐contamination when consecutive carcasses are submitted to classic inspection procedures. The microbial hazard used to illustrate the model was Salmonella, the data set was obtained from Brazilian slaughterhouses, and some simplifying assumptions were made. The model predicted that due to cross‐contamination during inspection, the prevalence of contaminated carcass surfaces increased from 1.2% to 95.7%, whereas the mean contamination on contaminated surfaces decreased from 1 logCFU/cm² to ?0.87 logCFU/cm², and the standard deviations decreased from 0.65 to 0.19. These results are explained by the fact that, due to carcass manipulations with hands, knives, and hooks, including the cutting of contaminated lymph nodes, Salmonella is transferred to previously uncontaminated carcasses, but in small quantities. These small quantities can easily go undetected during sampling. Sensitivity analyses gave insight into the model performance and showed that the touching and cutting of lymph nodes during inspection can be an important source of carcass contamination. The model can serve as a tool to support discussions on the modernization of pig carcass inspection.     

我国国有和民营上市企业风险倾向对比研究

文章旨在洞悉制度因素对企业风险行为影响的内在机理。通过我国国有和民营上市企业风险倾向实证对比, 结果发现:(1)金融危机爆发前, 在整体层面和行业层面上, 国有企业较民营企业都更倾向于冒险, 且二者间的差距不断缩减;(2)危机爆发后, 不同目标水平情况下, 国有和民营企业风险倾向间的对比较此前出现了一定变化;(3)在高于目标水平情况下, 国有和民营企业的风险倾向均与前景理论的预期相悖。这表明制度因素在很大程度上决定了我国企业风险行为, 同时, 企业自身改革、发展水平, 以及所处的经济大环境也会对其风险倾向产生一定的影响。因此, 我国企业风险管理机制构建应立足改革与发展, 努力实现政府、企业和市场多方联动, 内外兼修。     

引入人脸抓拍系统还是升级安检设备？——有限资源下的地铁暴恐防御序贯博弈模型

在有限防御资源约束下,地铁安防部门面临着引进人脸抓拍系统构建二级地铁暴恐防御体系,还是升级原安检系统构建增强型一级地铁暴恐防御系统的选择。本文基于暴恐分子决策的目标价值依赖性和安防部门的接警反应时间不对称性,构建了有限资源下地铁暴恐防御策略选择的序贯博弈模型。得出并分析了双方的四种均衡策略,最后结合北京地铁积水潭站早高峰案例,给出了考虑高峰大客流冲击效应的暴恐防御决策建议。研究发现,当增强型安检系统的准确率过高,或接警反应时间有效率较高时,引进人脸抓拍系统策略占优,且人脸抓拍系统的社会价值对安防部门决策无直接影响。当增强型安检系统的准确率适中,或接警反应时间有效率较低时,第一种情况,在安防部门侧重效率的情况下,人脸抓拍系统的社会价值与安防效率正相关,引进人脸抓拍策略在其社会价值较高时占优;第二种情况,在侧重安全情况下,升级加强原安检系统策略占优,此时,人脸抓拍系统的社会价值对安防部门决策无影响。另外,较高的安检准确率将提升安检厅的乘客淤滞水平、强化高峰大客流对安检厅的冲击效应、削弱高峰大客流对候车厅的冲击效应,并最终拉升暴恐分子直接袭击安检厅的风险。     

自动生产线的同步维修模型及实例研究

自动生产线故障停机时间长、停机费用高,其原因在于:设备种类多且相关联,存在各设备协同维修的难题。首先,寻求生产线故障时间和检查时间之间的平衡点,建立检查周期与总停机时间之间关系的目标函数。其次,借鉴同步维修的"对故障隐患集中式批处理,减少分散维修的停机时间"思想,以及时间延迟维修理论,建立生产线的同步维修模型,该模型利用生产线每天停机次数、每次停机时间及检查时发现的缺陷数,计算出合理的生产线检查周期,并以此为依据制定维修计划,实现"提高维修批量,减少生产线停机时间"的目标。最后,实例研究。收集某生产线近十年的故障记录数据,在分析生产流程、设备布局、各设备停机影响的基础上,提出对策指导生产线维修管理。     

政治意识与人性的悖论、融合——解读《红豆》

文学和政治的关系复杂微妙。文学既不能单纯成为政治的传声筒 ,又不能成为脱离生活意义的纯文学。产生于特定年代的《红豆》既囿于一定的政治环境 ,又对人性有所丰富和发展。为此应给予《红豆》客观的评价。在题材上 ,既是对 30年代“革命 +恋爱”主题的延续 ,又是对十七年文学中 ,描写革命战争或现实生活 ,迅速及时地配合政治需要的文学主潮流的一种背离     

Solving the Stochastic Growth Model by Parameterizing Expectations

This article describes a method for solving the one-good stochastic growth model by parameterizing the expectations part of the stochastic Euler equation. The conditional expectation is specified as a function of the state of the system, and the parameters of that function are estimated to solve the model. The article includes a discussion of how to find the parameters of the function and determine systematically the complexity of the functional form necessary to solve the model.