Social media and happiness nexus in the millennial generation

The current paper empirically examines the relationship between social media and happiness. Unlike existing works, we study this nexus from a global perspective using a cross-sectional model consisting of 140 countries on data from 2012 to 2017. Assuming that this effect may differ according to the average level of perception of happiness in each country, we use the quantile regression framework to yield more accurate inferences. The findings show that social media measured by Facebook penetration has a positive and significant relationship with happiness, and this positive nexus differs in terms of amplitude and significance throughout the conditional distribution of the happiness index. However, analysis in different samples reveal that this positive nexus is not universal and differs with the level of economic development of the countries and from one region to another. We put forward mental illness approximated by anxiety as the main transmission channel.     

便携式断面流量测量系统设计与实现

为便于进行明渠间流速流量及水深测量，设计一种便携式断面流量测量系统。根据现场环境对流速和测量水深要求，设计量程为20kPa高频压力敏感元件的压力传感器，在基于标准恒流源条件下，灵敏度优于0.25%FS；设计量程10m/s三叶锁存型霍尔效应磁敏传感器旋桨，利用水流动力推动旋桨运动获得旋桨转数，启动速度优于0.02m/s，精度优于2%；基于ARM Cortex?-M3内核作为逻辑处理单元，选用12位A/D转换器，实时存储并通过NB-Iot低功耗广域网上传数据至管理中心。该测量装置便于携带、质量轻，可单人单手操作、现场实时测量。     

Evolution of the internet gender gaps in Spain and effects of the Covid-19 pandemic

There is a widely accepted belief in new technologies that the digital divide in using a service will disappear as the service reaches an advanced level of maturity. The work presented here shows that this idea is debatable. Data from Spain, a country where daily internet users are 75.9 percent of the population, prove that the gender gap still exists. The paper explores if this gap can be entirely explained by the socioeconomic differences between men and women. We build a micro panel model and incorporate a set of socioeconomic variables (age, education, income, employment status, digital skills, and resident population) that allow us to isolate the effects of gender on the decision to become a daily Internet user. The results conclude that the Internet gap is a phenomenon with a specific gender component. Other things being equal a woman negatively affects the probability of using the Internet. Applying a similar model to 15 Internet services, we obtain that gender is always significant to explain the likelihood of being a user of each service. However, in some services (7 out of 15), the effect is favorable to women, and for other services (8), the gender effect favors men. The work concludes by analyzing the impact of the first wave of the Covid-19 pandemic on the use of Internet services, paying particular attention to its possible implications for the gender gap.     

唐山市规划区土体剪切波速与深度的相关性分析

针对唐山地区岩土勘察及地震工程中剪切波速随深度的经验值尚无通用标准的问题，对规划区209个钻孔剪切波速数据进行研究，通过回归分析法，建立不同地质分区和岩性条件下的回归分析模型，利用决定系数R2检验数据的拟合度，提出研究区的最优回归方程，并利用实际钻孔资料进行验证。结果表明，此次工作建立的回归方程式更准确、精度更高，可成为研究区工程开发建设的重要依据，并在节约成本、缩短工期等方面起到积极作用。     

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...