Effect of Parental Migration on the Academic Performance of Left‐behind Middle School Students in Rural China

China's rapid development and urbanization over the past 30 years have caused large numbers of rural residents to migrate to urban areas in search of work. This has created a generation of children who remain behind in rural areas when their parents migrate for work. Previous research has found mixed impacts of parental migration on the educational achievement of left‐behind children (LBC), perhaps because of methodological deficiencies and lack of recognition of the heterogeneity of this population of children. Our study attempts to examine the impact of six types of parental migration on the academic achievement of a rural junior high school sample. Our study uses a panel of 7148 junior high school students to implement a difference‐in‐difference analysis and finds that parental migration has a negative and significant impact on the academic achievement of junior high school students. Our study suggests that the Chinese Government should implement measures to dismantle barriers to the human capital accumulation of LBC to ensure sustainable economic growth and human capital development in China.     

Updating Input–Output Tables with Benchmark Table Series

Numerous methods have been proposed to update input–output (I–O) tables. They rely on the assumption that the economic structure will not change significantly during the interpolation period. However, this assumption may not always hold, particularly for countries experiencing rapid development. This study attempts to combine forecasting with a matrix transformation technique (MTT) to provide a new perspective on updating I–O tables. Under the assumption that changes in the trend of an economic structure are statistically significant, the method extrapolates I–O tables by combining time series models with an MTT and proceeds with only the total value added during the target years. A simulation study and empirical analysis are conducted to compare the forecasting performance of the MTT to the Generalized RAS (GRAS) and Kuroda methods. The results show that the comprehensive performance of the MTT is better than the performance of the GRAS and Kuroda methods, as measured by the Standardized Total Percentage Error, Theil's U and Mean Absolute Percentage Error indices.     

创新政策工具组合、创新能力与创新绩效研究

基于2008-2018年我国内地30个省市面板数据，采用面板固定效应模型分析创新政策工具及其交互项对创新能力及创新绩效的影响。结果发现：①供给型和环境型创新政策均有利于促进技术创新能力提升和创新数量增长，需求型创新政策对创新能力及创新绩效的影响均不显著；②需求型、环境型和供给型创新政策两两交互项能够显著提高基础创新能力和技术创新能力，并显著增加创新数量，但对创新质量均呈显著负向影响；③需求型与供给型以及需求型与环境型创新政策组合功能呈协同互补性特征，供给型和环境型创新政策组合功能呈竞争性特征；④基础创新能力在创新政策工具对创新质量的影响中发挥完全中介作用，技术创新能力在创新政策工具对创新数量的影响中发挥完全中介作用。     

基于可叠加物流箱的高效快递分拣策略

针对快件分拣效率低、货损高的问题,设计一种可叠加的物流箱,并基于该物流箱对快递流程进行改进。实现小型快件集装化,分拣作业模块化,提升快递分拣工作的效率和质量。     

在垄断中引入竞争：烟草行业规制改革的路径抉择

在现有的专卖政策和税收体制下,烟草商业企业缺乏竞争机制和生存压力,经营效率和服务水平难以提升。通过对我国石油、电力、电信等垄断行业的比较分析,本文探讨了烟草行业纵向分拆的背景、工业企业横向合并的现实,并基于此提出烟草商业系统引入竞争的理论方案,即通过标尺竞争和南北分拆,推动商业企业走向市场化道路。     

信贷合约内部机理及关键影响因素研究

以信号理论、信息不对称理论、关系型信贷理论以及债务代理成本理论等信贷合约相关理论为基础,围绕信贷合约的内部机理,即内生变量利率、担保和期限三者之闻的相互关系以及影响信贷合约的关键外生变量,提出了本文需要验证的若干核心理论假设,在考虑信贷合约要素利率、担保和期限内生性的情况下,建立了结构方程模型,最后对结构方程模型解的识别进行了验证并给出了结构方程模型的理论求解.