Optimal social security tax with myopic agents

Myopic agents lack the foresight to save for their own old age. It is generally believed that correcting myopia is a rationale for a pay-as-you-go (PAYG) pension system. This view has been supported by existing literature showing that the optimal PAYG social security tax should increase when people are more myopic. In this paper we obtain new results opposed to the traditional view. By establishing a very standard general equilibrium OLG model with myopic agents and endogenized marginal product of capital, we show that the optimal social security tax should be lower when people are more myopic. Our numerical analysis also shows that the welfare cost of the social security tax increases with people's degree of myopia. These results suggest that correcting myopia is not a clear rationale for the PAYG social security.     

浅析软煤层中顶层综采工作面回采初期技术管理

目前正处于煤炭行业的寒潮时期,各地煤炭企业亏损严重。为了响应国家的安全生产方针,煤炭企业在该时期生产过程中安全方面更不敢出一丝的问题。由于综采工艺相比其他采煤工艺而言大大提高了施工人员的安全系数。所以,综采工艺往往是工作面回采的首选。河南能源化工集团焦煤公司中马村矿同样采用了综采工艺对211021工作面进行回采。211021综采工作面为顶层工作面,并且所采煤层煤质较软,初采初放期间遇到了三条断层。下面就211021综采工作面回采初期的技术管理进行简要的分析总结。     

The long-run reversal in the long run: Insights from two centuries of international equity returns

We perform the most comprehensive test of long-term reversal in national equity indices ever done. Having examined data from 71 countries for the years 1830 through 2019, we demonstrate a strong reversal pattern: the past long-term return negatively predicts future performance. The phenomenon is not subsumed by other established cross-sectional return patterns, including the value effect. The long-term reversal is robust to many considerations but highly unstable through time. Finally, our findings support the overreaction explanation of this anomaly.     

Food insecurity,gender, and international migration in low- and middle-income countries

The determinants of migration have been widely studied but research has rarely addressed the roles of food insecurity and gender in the migration decision process. To address these gaps, we examine these relationships for 135,078 individuals across 94 low- and middle-income countries. We use a series of binary-choice models with sample selection and data from the 2014–2015 waves of the Gallup World Poll Survey, which includes the first global measure of individual-level food insecurity. Results, which are robust, indicate that food insecurity is an important determinant of both migration intentions and preparations, and the probability of migration intentions increase monotonically with the severity of food insecurity, and the probability of migration preparations decrease. These relationships also differ significantly by gender and level of gross national income. Evidence suggests a need for increased coordination between the international food security and migration policy agendas.     

Social protection for enhanced food security in sub-Saharan Africa

This paper identifies several positive synergies between social protection programmes and enhanced entitlements to food. One function of social protection is to manage or reduce vulnerability. Several instruments are reviewed – weather-indexed insurance, public works programmes, emergency food aid and buffer stock management – which aim to stabilise income and access to food across good and bad years, or between the harvest and the hungry season. Other social protection instruments aim to raise household income and crop production, for instance agricultural input subsidies or input trade fairs, as well as public works projects that construct or maintain physical infrastructure such as rural feeder roads. This paper also argues that entitlements to food can be strengthened if social justice principles are introduced to the design and delivery of social protection programmes. Examples reviewed include rights-based approaches such as employment guarantee schemes, community-based targeting and demand-driven accountability mechanisms. The paper concludes by arguing for a comprehensive approach to social protection that will achieve sustainable food security, by combining interventions that stabilise income or food production with those that raise income or food production, and are designed and delivered in ways that enhance social justice.     

平铝压条碾压装置的设计分析

为解决车用平铝压条生产效率低,装配困难的问题,本文设计了一套平铝压条碾压装置,阐述了该装置的结构布置及工作原理。经使用验证,该装置结构简单,易操作,同时提高了平铝压条装配工艺水平,降低了工人的劳动强度。     

Integrating retirement and permanent disability in NDC pension schemes

In this article, we develop a theoretical basis for integrating retirement and permanent disability using a generic nonfinancial defined contribution framework. The methodology we use relies on a multistate overlapping generations model that includes the so-called survivor dividend. Currently, this feature can only be found in the Swedish defined contribution (DC) scheme. The results achieved in the numerical example we present endorse the fact that the model works well. Special attention is given to the assumptions made about mortality rates for disabled people and disability incidence rates, which largely determine the contribution rate assigned to disability. The model could be of interest to policymakers because, after some adaptations, it could be implemented without too much difficulty and would uncover the real cost of disability and minimize the risk of disability insurance being used as a vote-buying mechanism.     

Managing security risks for inter-organisational information systems: a multiagent collaborative model

Information sharing across organisations is critical to effectively managing the security risks of inter-organisational information systems. Nevertheless, few previous studies on information systems security have focused on inter-organisational information sharing, and none have studied the sharing of inferred beliefs versus factual observations. In this article, a multiagent collaborative model (MACM) is proposed as a practical solution to assess the risk level of each allied organisation’s information system and support proactive security treatment by sharing beliefs on event probabilities as well as factual observations. In MACM, for each allied organisation’s information system, we design four types of agents: inspection agent, analysis agent, control agent, and communication agent. By sharing soft findings (beliefs) in addition to hard findings (factual observations) among the organisations, each organisation’s analysis agent is capable of dynamically predicting its security risk level using a Bayesian network. A real-world implementation illustrates how our model can be used to manage security risks in distributed information systems and that sharing soft findings leads to lower expected loss from security risks.     

数字化医疗信息安全管理机制研究

目前,我国在医疗信息安全保障建设方面严重滞后,信息安全工作的战略统筹和综合协调不够,缺乏体系化的安全策略研究以及针对数字化医疗业务特点的管理机制研究。为了实现安全可信的医疗信息发展环境,笔者针对现有医疗信息系统中各个需要实施安全保护的目标,给出了在推动医疗信息安全保障体系建设方面应涉及的各项安全问题及管理机制,旨在构建一个全面涵盖了信息技术、组织策略、法律意识的整体性治理方案。     

Optimizing suicide and trespass prevention on railways: a problem-solving model from the RESTRAIL project

Suicides and trespassing accidents result in more than 3800 fatalities in Europe, representing 88% of all fatalities occurring within the EU railway system. This paper presents a problem-solving model, which consists of a multistep approach structuring the analysis of a suicide or trespass-related problem on the railways. First, we present the method used to design, evaluate and improve the problem-solving model. Then we describe the model in detail: it comprises six steps with several subsequent actions, and each action is approached through a checklist of prompting questions and possible answers. At the end, we discuss the added value of this model for decision makers and its usability in the selection of optimal prevention measures.