Communication and Comovement: Evidence from Online Stock Forums

We study investor communication and stock comovement using a novel data set from an active online stock forum in China. We find substantial comovement among the returns of a stock and its “related stocks,” which are frequently discussed in the subforum dedicated to the given stock. Comovement is greater when the discussion of related stocks is more intensive. Further, the effect of communication on comovement is stronger for stocks associated with higher information uncertainty. Codiscussed stocks are more actively traded and experience more correlated trading. A trading strategy that exploits communication‐driven comovement generates abnormal returns. Our findings highlight the impact of investor communication on asset comovement.     

基于AD9361的掌上型LTE RRU设计与开发

当前小体积远端射频单元（Remote Radio Unit,RRU）主要是皮站级别的Pico-RRU，其重量和体积仍然难以满足掌上型的要求。为此，采用高集成度的AD9361芯片来实现长期演进（Long Term Evolution，LTE）宽带收发信机功能，配合时钟同步模块、放大器模块和控制接口电路等一起构建低成本的掌上型RRU。主要解决了基于AD9516的时钟同步、低相位噪声设计和高灵敏度接收机设计三个技术难点，成功实现了掌上型、高性能、低成本的设计目标。整个RRU样机尺寸为18 cm×10 cm×2 cm，质量约500 g，量产成本千元以内。测试表明，该RRU下行误差向量幅度（Error Vector Magnitude，EVM）小于3%，优于3GPP要求的8%；10 MHz带宽时上行接收机灵敏度优于3GPP要求的-93.5 dBm。     

VIX term structure and VIX futures pricing with realized volatility

Using an extended LHARG model proposed by Majewski et al. (2015, J Econ, 187, 521–531), we derive the closed-form pricing formulas for both the Chicago Board Options Exchange VIX term structure and VIX futures with different maturities. Our empirical results suggest that the quarterly and yearly components of lagged realized volatility should be added into the model to capture the long-term volatility dynamics. By using the realized volatility based on high-frequency data, the proposed model provides superior pricing performance compared with the classic Heston–Nandi GARCH model under a variance-dependent pricing kernel, both in-sample and out-of-sample. The improvement is more pronounced during high volatility periods.     

金正恩时代的朝鲜经济体制转型研究

采用转型政治经济学的理论框架,分析金正恩时代的经济改革可以发现,朝鲜在经济战略、价格、市场、产权和经营权、对外经济、金融、财税等领域采取了一系列改革措施,日益呈现出计划经济向市场经济过渡的转型特征。金正恩的经济改革不是经济管理方式的浅层变化,而是经济体制的转型。朝鲜经济体制转型虽取得一定成果,但仍面临着国际制裁、国内制度建设滞后等约束条件,迫切需要在无核化问题上继续前进和进一步的改革。朝鲜经济体制转型有利于推动朝核问题解决和东北亚地区合作进程,各国应据此制定针对性的对朝政策。.     

The Effects of Search-Related and Purchase-Related Mobile App Additions on Retailers’ Shareholder Wealth: The Roles of Firm Size,Product Category,and Customer Segment

Mobile channel additions have been shown to increase consumer-brand relationships, brand satisfaction towards and overall purchasing from a retailer, but what is less apparent is whether shareholders are fully rewarded for retailers’ mobile channel additions. Results from an event study on 115 announcements relating to mobile app additions of publicly traded U.S. retail firms between 2009 and 2016 indicate that the stock market responds generally positively to mobile app additions, but specifically to the two mobile app addition types. Stock market responses to search-related and purchase-related app additions are moderated by firm size, product category, and target customer age. For announcements of search-related apps, the market responds more positively to product retailers than to service retailers, and to small firms than large ones. For announcements of purchase-related apps, the market responds less positively to firms that target younger customers than firms who do not especially target them.     

天地一体化信息网络中天基卫星网络架构设计

为了充分利用各种空间设施资源，提升天基信息网络覆盖与传输能力，分别从天基信息网络体系架构和逻辑功能架构角度进行了系统性设计。与以往天基网络的设计不同，该设计更注重各类卫星网络的深度融合应用，为此将网络虚拟化技术引入天基卫星网络。同时，还提出了解决新架构下卫星组网难题的方法，将电磁涡旋、卫星灵活载荷和边缘计算技术设计到天基网络。仿真表明，所提出的架构能有效提升频谱利用率和减少卫星网络信令开销。     

DO FIRMS SEEK A TARGET BOARD STRUCTURE? EVIDENCE FROM THE POST‐SOX PERIOD

We investigate whether firms restructure board composition to align with changes in their contracting environment. Board size and independence increase with firm complexity, consistent with theoretical predictions. However, the hypothesized negative relation between board independence and information costs is evident only for firms completing acquisitions. Furthermore, board independence increases to offset increases in CEO power in a sample of firms making acquisitions, but decreases when CEO power increases in a large cross‐section of firms. We conclude that after the Sarbanes–Oxley Act of 2002, firms face constraints adjusting to target board structure, but these constraints can be mitigated by a shock to the contracting environment via acquisition.     

知识型员工双重社会网络对企业创新绩效作用机制研究

基于企业基础资源观和组织学习理论，从知识型员工个人和组织社会网络两个方面构建知识型员工双重社会网络影响企业创新绩效的理论模型，分析知识共享、组织学习及资源整合在员工双重社会网络对企业创新绩效影响机制中的作用。结果表明：知识型员工双重社会网络对科技型企业创新绩效的作用路径有3条，资源获取与整合、知识共享与学习及员工动态创新能力分别在其中发挥中介作用；在不同类型组织文化环境中，知识型员工双重社会网络对企业创新绩效的作用特征、作用重点以及作用机制存在显著差异，内部整合维度主要通过知识共享和组织学习影响企业创新绩效，外部适应维度主要通过隐性知识传播和资源整合影响企业创新绩效。     

The Short-Selling Hypothesis of Weekend Effect and T + 1 Trading Mechanism

Asia-Pacific Financial Markets - Utilizing a difference-in-difference regression model, we conduct cross-sectional and time-series analysis to explore effect of short sales on the weekend effect in...