Group heterogeneity and the economic effect of farmer organisation participation: Empirical evidence from Taiwan

We explore the effects of different farmer organisations on smallholder farmers' economic performance. The average treatment effect of switching between different farmer organisations is examined. In addition, based on the premise that a higher level of social capital is accumulated through participation in multiple farmer organisations, we also investigate how the economic consequences of farmer organisation membership vary with the intensity of participation. Our conceptual model explicitly includes social capital to provide a micro-foundation and a theoretical justification for the linkage between farmer organisation participation and the economic outcome. This indicates that participating in different types of farmer organisations is beneficial for farm households only when the returns from social capital investment outweigh the time cost of participation. Our empirical results suggest that membership of farmer organisations that are more homogeneous in terms of member specialty and similarity in production and marketing activities results in a significant increase in farm sales revenue and net returns. This result supports the view that technological proximity accentuates knowledge spillovers within the farmer organisations, and thus leads to better economic outcomes. In line with the prediction of the theoretical model, the average treatment effect of participation is found to increase with the number of organisations that farmers belong to. Moreover, results from the quantile regression provide empirical evidence supporting increasing returns to social capital accumulated through participation in several farmer organisations.     

江苏沿海地区的风能资源模拟的时空分布

通过选取最优的WRF参数化方案组合,对各季代表月进行江苏沿海地区的风能资源数值模拟,验证模拟结果的可信度。模拟结果为风速分布变化受海陆差异影响较大,受热不均,沿海风速梯度变化明显且较密集,江苏地区风能资源相对丰富。风速随高度的增大而增大,且最高层受海陆分布差异影响最小,风场的季节性特征明显。最终对比结果表明:WRF模式较好地体现风速变化规律,为江苏沿海地区风能资源开发利用提供科学依据。     

信息中心网络中基于节点缓存命中贡献率的缓存替换方案

信息中心网络（CCN）是一种全新的网络架构，其显著的特点是处处缓存，合理的内容缓存部署能够显著提高网络传输效率。缓存替换策略是缓存管理中的重要组成部分，合理地进行缓存内容的替换，成为影响网络整体性能的关键。考虑到内容自身的特性，设计了一种基于节点缓存命中贡献率的贪婪双倍命中（GDH）缓存替换方案。该方案综合考虑了内容的请求次数、传输代价、缓存代价，设计全新的多目标价值函数，用于评估内容的缓存价值，当缓存空间不足时，替换掉价值最小的内容，实现节点缓存内容价值的最大化。仿真结果表明，该替换算法提高了节点的命中率，降低了获取内容的平均跳数。     

Does job mismatch affect wage earnings among business and management graduates in Vietnam?

This paper investigates the wage penalty resulting from horizontal job mismatch among wage earners with university degrees in the fields of business and management. The study utilizes pooled cross-sectional data from the Labour Force Surveys (LFS) in 2018, 2019 and 2020 in Vietnam. We employ instrumental variable (IV) estimators to address the potential endogeneity of job mismatch. Estimates from the ordinary least square (OLS) and IV methods show that job mismatch has a negative effect on wage earnings and that the penalty for such mismatches is nearly double for men than for women. Also, for mismatched graduates in the private sector, the wage penalty is nearly triple what it is for those in the public sector. Notably, we find that the wage penalty is substantial for those under 50, but less so for those over 50. This suggests that education-specific skills can be substituted by work experience to some extent.     

A multi-stage stochastic programming approach for pre-positioning of relief supplies considering returns

A dynamic pre-positioning problem is proposed to efficiently respond to victims’ need for relief supplies under uncertain and dynamic demand in humanitarian relief. The problem is formulated as a multi-stage stochastic programming model that considers pre-positioning with the dynamic procurement and return decisions about relief supplies over a time horizon. To validate the advantages of dynamic pre-positioning, three additional pre-positioning strategies are presented: pre-positioning with one-time procurement and without returns, pre-positioning with one-time procurement and returns, and pre-positioning with dynamic procurement and without returns. Using data from real-world disasters in the United States in the Emergency Events Database, we present a numerical analysis to study the applicability of the proposed models. We develop a sample average approximation approach to solving the proposed model in large-scale cases. Our main contribution is that we integrate dynamic procurement and return strategies into pre-positioning to decrease both costs and shortage risks in uncertain and dynamic contexts. The results illustrate that dynamic pre-positioning outperforms the other three strategies in cost savings. It also indicates that a higher return price is particularly helpful for decreasing unmet demand. The proposed models can help relief agencies evaluate and choose the solutions that will have the greatest overall effectiveness in the context of different relief practices.     

Edgeworth's taxation paradox when firms engage in cost-reducing investment

This study examines whether and when Edgeworth's taxation paradox, that taxation decreases the equilibrium price, occurs in a free-entry Cournot oligopoly with cost-reducing investment. In contrast to the fact that no paradox occurs in the short-run equilibrium, the paradox can occur in the long-run equilibrium, in which the number of firms is endogenous. However, the conditions under which the paradox occurs are restrictive when there is no investment. By incorporating cost-reducing investments into the model, we demonstrate that the paradox is likely to occur under less restrictive conditions, irrespective of whether the tax is specific or ad valorem.     

企业特征、行业特征对工业企均用地规模的影响 ——以江苏省为例

研究目的：以江苏省制造业为研究对象，分析工业企均用地规模的企业特征、行业特征及空间差异，并探讨企业特征、行业特征对工业企均用地规模的影响。研究方法：空间回归模型。研究结果：（1）江苏省工业企均用地规模为1.08 hm2/家，存在明显的空间差异，总体上呈现由北向南递减的态势。（2）工业企均用地规模在土地权属和企业规模上存在较大差异。国有土地上的工业企均用地规模为1.37 hm2/家，远高于集体土地上的工业企均用地规模0.66 hm2/家；企业规模越大，工业企均用地规模越大。（3）江苏省各行业工业企均用地规模存在明显差异。高新技术企业和非高新技术企业的工业企均用地规模分别为3.57 hm2/家和0.98 hm2/家；战略性新兴产业与非战略性新兴产业的工业企均用地规模分别为4.28 hm2/家和1.02 hm2/家。（4）土地权属、企业规模和行业特征与工业企均用地规模正相关，经济发展水平、产业结构和政策强度对工业企均用地规模起显著的控制作用。研究结论：工业用地供应需考虑区域差异，针对不同企业特征和行业特征实施差别化的供地方式与标准，提高工业用地利用标准约束，控制国有土地、高新技术企业和战略性新兴产业工业用地供应的宗地规模。     

Average skewness in global equity markets

This paper examines the predictive power of average skewness, defined as the average of monthly skewness values across stocks, documented by the prior literature for US market returns in an international setting. First, we confirm the validity of the results in the original study and show that the intertemporal relation between average skewness and aggregate returns becomes weaker in an alternative sample period. Second, when we repeat the analysis in 22 developed non-US markets, we find that average skewness has no robust predictive power for future market returns. The loss of forecasting power in the international sample does not depend on the method used to calculate average skewness or the regression specification and is supported by additional out-of-sample tests and subsample analysis.     

基于轻量级卷积神经网络的苹果表面缺陷检测方法

为了解决目前农业信息领域对苹果表面缺陷检测准确率低的问题,提出一种基于轻量级卷积神经网络的苹果表面缺陷检测方法.首先采集苹果缺陷样本图片制作实验数据集用于模型训练和测试;其次在AlexNet网络结构的基础上,引入深度可分离卷积代替原有网络中的标准卷积运算来进行图像特征的提取;最后利用全局平均池化方法代替原有网络中的全连...