重大突发公共卫生事件科技研发应急体系运行机制研究

在突发事件应急管理过程中，科技研发支撑作用十分关键，亟需建立突发公共卫生事件科研应急体系长效运行机制。基于科技研发应急体系的复杂性、适应性特征，从主体属性和体系架构两个层面入手，分析重大突发公共卫生事件科技研发应急体系的复杂适应系统特征，运用复杂适应系统理论模型和动态闭环螺旋模型，研究重大突发公共卫生事件科技研发应急体系运行机制。研究发现，重大突发公共卫生事件背景下，科技研发应急体系具有复杂适应系统的7个基本特征，是典型的复杂适应系统；科技研发应急体系中，科研攻关专家组、诊疗医院、科技部门等科研主体具有各自内部模型，并通过6大标识进行聚集；科技研发应急体系存在事件—需求引导、主体协同、资源交互、成果转化机制。同时，新冠病毒肺炎疫情应对实践表明，疫情防控救治进程中科技研发应急体系存在并遵循上述运行机制。     

数字地面模型新进展：TIN2.0、3D表面 塑型线和自由形态建模工具

竖向设计是人类在景观中进行的基本活动。人类对 室外空间的任何干预都涉及对地表形态的设计。在过去的几十 年中，数字设计的发展不仅改变了表现的方法，而且改变了设 计的过程。就地形建模而言，该技术实现了三维可视化和任务 自动化，例如土方计算和自动产生横截面。但在重点考察最新 的建筑信息模型(BIM)如何应用和实施这项技术时，不难发现 地形建模过程并没有充分利用技术带来的潜在优势。实际上， 三维建模工具、基于组件的建模和分析、设计验证，以及协同 设计是可以集成到数字地面模型中的。识别了现有数字建模解 决方案中的主要缺陷并为其进一步发展提供机会，提出了一 项整合性的数字地面模型建模过程，该过程引入了TIN2.0曲 面，对现有的TIN曲面进行了升级，允许在同一曲面中同时存 在规则三角网和不规则三角网，并开发了一套基于三维线和自 由形态设计工具的建模工具，推动风景园林信息模型框架的发 展以满足风景园林师及其他专业人士，如建筑师和土木工程师 进行地形建模的需求。通过案例研究对提出的建模过程进行了 测试和验证。结果表明，生成的数字曲面具有较高精度，可以 具象地表现地形，允许设计过程在三维线或自由形态设计工具 的基础上进行。所有地形建模均在三维数字模型上进行     

城市近郊区农户土地投入行为绩效评价及障碍因子诊断 ——耕地多功能价值视角下的多群组对比分析

研究目的:基于耕地多功能价值的视角研究农户土地投入行为绩效并诊断其障碍因子,以探索当前形势下城市近郊区农户"既不愿意种地,又不愿意将土地流转"的深层原因.研究方法:在构建农户土地投入行为绩效分析框架的基础上,通过农村入户调查获得样本数据,采用熵权TOPSIS法和障碍度模型,对不同性别和年龄阶段农户的土地投入行为展开绩效分析.研究结果:总体上,城市近郊区农户的土地投入行为绩效水平为"良好";多群组对比分析显示,男性绩效水平高于女性,青壮年绩效水平高于老年;补贴标准偏低和职业认同感差是制约土地投入行为绩效的主要障碍因子,而满足就业和养老需求依然是耕地资源的核心价值功能.研究结论:耕地在农户认知层面发挥着"弱保障"功能,"存而不用"的保守心态在事实上导致家庭承包地处于闲置、撂荒状态,这便是当前形势下城市近郊区耕地资源低效利用的底层逻辑.     

农民工教育与职业的匹配及其工资效应——基于城市规模视角

农民工教育与职业的匹配状况对提高劳动力资源利用、增加劳动供给质量具有重要意义。本文使用中国流动人口动态监测调查2011~2016年微观数据,基于城市规模视角分析了农民工教育与职业的匹配状况对工资效应的差别。研究发现:人口规模越大的城市,农民工教育与职业的错配比例越高;中小城市农民工教育过度对工资的影响呈现工资嘉赏效应,大城市农民工教育过度对工资的影响以工资惩罚为主;而教育不足对农民工工资则普遍存在负向影响。农民工教育与职业不匹配对工资影响的理论机制表明,中小城市支持人力资本理论模型,而大城市和特大城市则支持分配理论模型。这意味着,农民工在中小城市表现出学历越高人力资本回报越高的特点;而在大城市,教育与职业适配则更为重要。因此,改善城市层面的教育-职业的适配性,让农民工在城市劳动力市场上自由流动和工作转换,进一步增强城市间劳动力资源的流动是相关政策调节的重点。     

Objective methods for graphical structural learning

Graphical models are used for expressing conditional independence relationships among variables by the means of graphs, whose structure is typically unknown and must be inferred by the data at hand. We propose a theoretically sound Objective Bayes procedure for graphical model selection. Our method is based on the Expected-Posterior Prior and on the Power-Expected-Posterior Prior. We use as input of the proposed methodology a default improper prior and suggest computationally efficient approximations of Bayes factors and posterior odds. In a variety of simulated scenarios with varying number of nodes and sample sizes, we show that our method is highly competitive with, or better than, current benchmarks. We also discuss an application to protein-signaling data, which wieldy confirms existing results in the scientific literature.     

Trading volume and stock returns: A meta-analysis

I examine 468 estimates on the relationship between trading volume and stock returns reported in 44 studies. I study publication bias together with Bayesian and frequentist model averaging to explain the heterogeneity in the estimates. The results yield three key conclusions. First, publication bias distorts the findings of the primary studies. Second, the predictability of stock returns varies with different markets and stock types. Third, different data characteristics, structural variations and methodologies used drive the heterogeneity in the results of the primary articles. In particular, one should be cautious when using monthly data or VAR models.     

Optimal model averaging forecasting in high-dimensional survival analysis

This article considers ultrahigh-dimensional forecasting problems with survival response variables. We propose a two-step model averaging procedure for improving the forecasting accuracy of the true conditional mean of a survival response variable. The first step is to construct a class of candidate models, each with low-dimensional covariates. For this, a feature screening procedure is developed to separate the active and inactive predictors through a marginal Buckley–James index, and to group covariates with a similar index size together to form regression models with survival response variables. The proposed screening method can select active predictors under covariate-dependent censoring, and enjoys sure screening consistency under mild regularity conditions. The second step is to find the optimal model weights for averaging by adapting a delete-one cross-validation criterion, without the standard constraint that the weights sum to one. The theoretical results show that the delete-one cross-validation criterion achieves the lowest possible forecasting loss asymptotically. Numerical studies demonstrate the superior performance of the proposed variable screening and model averaging procedures over existing methods.     

金融资源配置、技术进步与经济高质量发展

随着我国发展阶段及内外部条件的变化,科技创新已成为新时代引领我国经济高质量发展的核心驱动力。本文以金融驱动技术进步的视角,构建内生增长DSGE模型,分析金融资源配置、技术进步和经济增长之间的关系。研究佐证了我国技术创新的逆周期性,并发现金融资源在企业生产性投资与创新投资之间的分配,可以通过改变生产要素投入规模和技术进步率两种途径影响经济增长,且这两种影响之间存在“跷跷板”关系,但后者更具主导性。在此基础上,诠释了金融、技术与经济的动态传导机制:经济扩张期,企业生产规模扩张,金融资源对生产性投资的支持增加,对创新的投入相对减少,技术进步率放缓;经济收缩期,企业缩减生产规模,金融资源对生产性投资的支持减少,对创新的投入相对增加,技术进步率提升。本研究的政策启示为,面对当前发展新矛盾、新挑战,应把握发展新格局、新机遇,进一步深化金融改革,优化金融资源配置机制,鼓励创新投资,充分发挥股权市场对企业研发创新的支持作用,并辅以稳健适度的宏观调控政策,为企业创新提供良性的宏观环境,激活企业创新需求,促进技术进步,推动经济高质量发展。     

Exploring the development trend of internet finance in China: Perspective from club convergence

We first employ β-conditional convergence and log t regression tests based on nonlinear time-varying factor model and club clustering algorithm to analyze the convergence characteristics of the development level of Internet finance in 335 prefecture-level cities in China. The result of log t regression test illustrates that there is no convergence as a whole in the development level of China's Internet finance. However, seven convergence clubs and a divergent group have been formed, and the development level and growth rate of Internet finance among these convergence clubs have shown obvious differences. Moreover, we also employ the Ordered Probit to explore the formation mechanism of the convergence clubs. The results reveal that the regions with a higher level of economic development, traditional financial development, economic openness and Internet development are more inclined to converge in a club with a higher Internet finance development level. Alternatively, the regions that are interfered with more by the government or that have a lower degree of marketization, tend to converge in a club with a lower level. Finally, according to the conclusions, we propose corresponding policy recommendations for promoting the regional coordinated development of China's Internet finance.     

预期寿命、生育率变动与基本养老保险统筹账户调整

在构建三期世代交叠模型的基础上，通过选取相关制度指标来模拟分析在未来预期寿命和生育率变动下，基本养老保险统筹账户如何基于参数调整来维持收支平衡。研究结果表明：（1）我国居民预期寿命增长过快，统筹账户收支平衡受预期寿命变化影响较大；（2）在现阶段的预期寿命和生育率条件下，统筹账户能实现自身收支平衡，而且可在短期内通过阶段性降低缴费率来促进制度长远发展；（3）在长期内需通过提高缴费率或降低养老金替代率来保证统筹账户收支平衡，预期寿命为87.828岁且总和生育率为1.79作为参数调整临界点；（4）以现有制度设计为基准，参数调整临界点之前保证35%的基础养老金平均替代率不降，临界点之后保证20%的缴费率不升可以最大程度促进经济和社会发展。