The social process of internet appropriation: Living in a digitally advanced country benefits less well-educated Europeans

We generalize and extend the sequential model proposed by the resources and appropriation theory to explain the digital divide in the European Union plus the United Kingdom (EU27+UK). We measure the theoretical constructs of the model with data provided by the EU and test the theoretical predictions using a partial least squares structural equation model. We find support for the hypothesized relationships but find that the effects vary depending on the digital development level of countries. While education overall is the primary determinant of the social production of digital inequalities, a country's digital development level is crucial for less well-educated Europeans. These findings have theoretical and practical implications: (1) they call into question the homogeneity of the effect of causal relationships and the assumption that individuals differ only in terms of motivation, access, and digital skills, and (2) they indicate that socially disadvantaged Europeans benefit from living in more digitally developed countries.     

紧邻老旧民房的深孔松动控制爆破技术

为了保护融水至河池高速公路二分部项目K53桩号附近的老旧民房和村民祠堂,控制露天深孔台阶爆破开挖所产生的振动和飞石、滚石等有害效应对村庄的影响,通过采用露天深孔松动控制爆破的方法,利用数码电子雷管结合毫秒级延期起爆网络进行爆破参数的设计。严格控制单段最大起爆药量,预留靠近民房山体一侧做掩体,确定好延时时间间隔和抵抗线方向以及做好炮孔堵塞和炮孔覆盖等安全技术措施,从而减少爆破振动和飞石、滚石等有害效应。结果发现:爆破效果良好,无飞石和滚石发生,大块率较低,机械易于开挖。祠堂和民房地基采集到的振速数据远低于安全振动峰值。     

Beyond antitrust populism: Towards robust antitrust

The populist use of competition policies is on the rise again, associated with the growth of big-tech companies in the era of digital platforms. This article sees antitrust populism as a re-emerging force in the United States and Europe via greater politicisation of competition law enforcement. It addresses the basic tenets of antitrust populism in order to expose the fundamental problems that populist use of competition law entails. I argue for a rethink of antitrust policy on the intellectual foundations laid down by what Mark Pennington describes as ‘robust political economy’. We need greater regulatory humility and antitrust enforcement which takes both innovation and welfare seriously.     

全空域球面相控阵波束形成器的优化设计

针对目前全空域球面相控阵测控系统工程应用中波束数量、信号瞬时带宽等数字波束形成器性能和复杂度难以兼顾的问题，分析了常规波束形成方法在基于半球形结构的S频段大型共形天线阵列工程应用中的局限，给出了一种基于子阵划分的宽带数字波束形成器优化设计方法，通过优化幅相和时延补偿方式，使算法不受子阵尺寸限制，工程实现复杂度较低。系统建模和仿真验证表明该方法可以获得良好的瞬时带宽性能，具有较好的工程应用价值。     

我国物流业2019年发展回顾与2020年展望

2019年是中华人民共和国成立70周年,也是物流业稳中有进、变中求新的一年。面对严峻形势,我国物流业顶住下行压力,实现平稳运行,取得多方面进展。具体而言,一是社会物流需求增速持续放缓,总体运行缓中趋稳;二是物流需求结构持续优化,物流供给结构稳步升级,供需结构加速调整;三是科技应用引领数智化转型,科技赋能物流数智化、平台化;四是新兴的供应链服务企业向标准化发展迈出了重要一步,供应链创新发展进入新阶段,现代供应链成为新亮点;五是物流基础设施网络加快升级,物流枢纽网络建设进入实质推进阶段,助力枢纽经济发展;六是物流业"走出去"空间加大,国际物流打开对外开放新局面,我国对外投资合作与对外援助执行保持平稳有序健康发展;七是绿色物流配合污染防治攻坚战,绿色可持续物流取得新进展;八是物流政策落地,物流企业获得感增强,从业人员稳定性增强,物流营商环境持续改善。2020年,我国经济稳中向好的基本趋势不会改变,物流业平稳增长的总体方向不会改变,物流业主要经济指标将继续保持平稳增长,但物流业下行压力依然较大,发展不平衡、不充分矛盾依然比较突出,与人民群众日益增长的美好生活需要和现代化经济体系建设的要求相比依然存在差距,高质量发展任重道远。在新的一年里,为更好地推动我国物流业发展,一要平衡物流稳增长与高质量发展关系,决胜全面建成小康社会;二要坚持目标导向,探索新时代物流业发展的新使命新要求;三要突出新发展理念,推动传统数量型降成本向效率型降成本转变;四要深化产业联动融合,从低水平粗放式发展向精细化、高品质发展转变;五要坚持科技引领和技术驱动,激发物流业高质量发展新动能;六要推进国家物流枢纽联盟工程和全国百家骨干物流园区互联互通工程,建设物流基础设施网络;七要配合"一带一路"倡议,推动国际物流合作与交流;八要进一步处理好政府与市场、国家与地方、市场与企业的关系,营造政府、企业与协会合力推动物流业高质量发展的产业生态圈。     

熵值法下我国数字经济发展水平动态评价研究——基于省际面板数据

以数字经济的内涵和本质为基础,建立我国30个省市区的数字经济发展水平评价体系,采用熵值法测算2013~2017年我国各省份数字经济发展状况。研究发现,区域创新能力不足是制约我国数字经济发展的效率短板;各地区济数字经济发展水平整体上呈上升式发展,但仍存在较显著的区域差异:东部地区的数字经济发展水平明显高于中西部地区,而中西部地区数字经济增长速度高于东部地区、与东部地区的相对差距略微缩小、绝对差距依然扩大。根据研究结果,我国应从推动数字经济技术创新、加强区域经济合作和因地制宜发展区域经济等方面推动区域数字经济发展。     

云计算中的轻量级查询结果验证机制

存储在云计算服务器上的数据可能被篡改或删除，查询完整性验证的作用是确保查询用户能够验证查询结果中的数据是真实的，且包含所有满足条件的数据。提出了一种基于签名链结构的查询完整性验证机制。方案使用代数签名机制替代数字签名实现校验值的计算，从而有效降低计算和查询验证开销。此外，通过维护一种新的、简单的索引结构实现了仅需下载少量数据即可实现校验值的更新。实验结果表明，所提方案比基于数字签名的签名链方案具有更小的更新开销和更高的验证效率。     

Digital sport entrepreneurial ecosystems

The entrepreneurial ecosystems literature has increasingly explored network relationships between different stakeholders, as well as the role of context. This article addresses the challenge of including a sport context in the entrepreneurial ecosystem literature thereby contributing to the sport entrepreneurship literature by bringing insights from entrepreneurship ecosystem research. In‐depth interviews of football stakeholders in the sport entrepreneurship ecosystem are conducted in terms of understanding the emergence of digital sport start‐ups. The issues raised help explore the changing nature of digital entrepreneurial ecosystems to take into account new sport technological advances. Mixed embeddedness theory is used as the conceptual foundation to understand sport digital entrepreneurial ecosystems. Key management practices are identified in terms of sport start‐ups participating in entrepreneurial ecosystems. The article concludes by making suggestions for future research.     

Effects of consumer cohorts and age on meat expenditures in the United States

Meat demand is likely influenced by the birth cohort and age of the individual. In this study, we examine the demand for beef, pork, poultry, and other meat in the United States using the 1984–2012 Consumer Expenditure Survey and the almost ideal demand system with the incorporation of age, period, and cohort (APC) effects. We find that the model with APC effects performs better than the models without APC effects. The results indicate that cohorts born in earlier time periods are expected to purchase significantly less poultry compared to cohorts born in later time periods, when they are measured at the same age. Over the life cycle, purchase of poultry is expected to increase with age while the opposite is true for red meat. We also find that the own-price elasticity for beef is highest among the products examined, while the own-price elasticity for other meat is lowest and the inclusion of APC effects increases the absolute value of the own-price elasticities for beef, pork, and poultry, but reduces the own-price elasticity for other meat. Our forecasts indicate that the aggregate poultry purchase will continue to increase until 2022, while the aggregate purchase of red meat will slightly increase until 2017, but will either decrease or stay at same level from year 2017 to 2022.     

基于数字足迹的乡村旅游流空间结构特征--以浙江省湖州市为例

乡村旅游是乡村振兴的有效路径,也是近年来研究热点,而在乡村旅游流领域研究相对不足。以湖州乡村旅游地为案例,通过对大样本数字足迹的数据处理,分析乡村旅游流空间结构特征,总结空间行为偏好。结果表明:①乡村旅游数字足迹呈现全年双峰值、月度差异不大的时间特征,"双核"多组团的空间分布特征,以及古镇、古村、民宿等带有文化符号旅游景观导向的空间偏好特征;②网络密度0.27的乡村旅游流空间结构由连接度高的34个节点构成,除核心吸引的双核外,民宿集聚区构成了网络结构的核心点;③传统旅游吸引物、民宿集聚区等节点呈现较强的网络中心性,节点的网络结构特征反映乡村旅游流空间呈现的地理临近性,以及区域空间集聚、扩散与联动发展效应。依据研究结论提出"完善与发挥节点集聚扩散功能,增强节点对数字足迹的有效吸引力,提升乡村旅游经济发展质量,助力乡村振兴"的发展策略。