POI结构化和非结构化数据存储检索策略

POI（兴趣点）数据具有结构化和非结构化属性，使用关系型数据库存储时，非结构化占用内存空间大，检索时直接从数据库读取，且POI空间信息需要通过HBase的rowkey进行多条件检索，效率低下。通过研究POI数据特点，构建数据模型，针对POI结构化属性数据和非结构化数据提出不同的存储和检索策略并创建索引。最后使用Sqoop 完成 POI 属性数据和非结构化数据的交互并嵌入Solr 技术进行检索。经实验验证，应用该方法针对POI非结构化数据检索效率有所提高。     

Pandemic-driven financial contagion and investor behavior: Evidence from the COVID-19

This paper studies the pandemic-driven financial contagion during the COVID-19 period and the impact of investor behavior on it by constructing three types of direct behavior measurements based on Google search volumes. More specifically, using a sample of 26 major stock markets around the world during the COVID-19 pandemic, we construct a non-linear financial contagion network via a dynamic mixture copula-EVT (extreme value theory) model to quantitatively detect and measure the complex nature of pandemic-driven financial contagion. Furthermore, through constructing direct investor behavior measurements including investor attention, sentiment, and fear, we find investor behavior plays an important role in explaining pandemic-driven financial contagion. We also find that the impacts of investor behavior on the pandemic-driven financial contagion are heterogeneous under several different settings, including market conditions, market development levels, regional subsets, and contagion directions.     

基于WEB挖掘的虚拟企业合作伙伴选择研究

将基于WEB的文本挖掘应用到虚拟企业合作伙伴选择过程中,通过已有的网页搜集、文本过滤、信息抽取等相关文本处理技术自动提取Internet上企业的相关信息,从而为核心企业提供大量的潜在伙伴信息,缩短虚拟企业组建时间,提高核心企业市场反应速度。     

再论Internet网上药学资源的利用

21世纪是一个信息化的时代,Internet的产生使信息资源共享成为现实。更重要的是Internet中包含着大量的最新医药资料,它在药学领域的各个方面都有极大的应用价值。文献[1]主要介绍了Internet的入门和初步利用网上药学资源的方法。现在笔者向广大药学工作者做进一步的介绍。1　重要的药学网址[2,3]1.1　主要的中文药学信息资源1)大学、研究所、图书馆等药学研究所设立的专业网站,如:中国生物医学文献数据库,http://www.imicams.ac.cn/cbm.html由中国医学科学医学信息所网站提供,可用免费帐号test检索更新数据库(即尚未采用光盘出版的文…     

Structural transmissions among investor attention,stock market volatility and trading volumes

We employ data-based approaches to identify the transmissions of structural shocks among investor attention measured by Google search queries, realised volatilities and trading volumes in the United States, the United Kingdom and the German stock market. The two identification approaches adopted for the structural vector autoregressive analysis are based on independent component analysis and the informational content of disproportional variance changes. Our results show robust evidence that investors' attention affects both volatilities and trading volumes contemporaneously, whereas the latter two variables lack immediate impacts on investors' attention. Some movements in investors' attention can be traced back to market sentiment.     

Nonlinear Employment Effects of Tax Policy

We study the nonlinear propagation mechanism of tax policy in a heterogeneous-agent equilibrium business cycle model with search frictions in the labor market and an extensive margin of employment adjustment. The model exhibits endogenous job destruction and endogenous hiring standards in the form of occasionally-binding zero-surplus constraints. After parameterizing the model using U.S. data, we find that the dynamic response of employment to a temporary change in the labor income tax is highly nonlinear, displaying sizable asymmetries and state dependence. Notably, the response to a tax rate cut is at least twice as large in a recession as in an expansion.     

改进萤火虫算法在Okumura-Hata模型修正中的应用

针对Okumura-Hata模型在不同区域对电波传播衰减的预测与实测难以匹配的问题，提出了一种Okumura-Hata模型修正方法。提取Okumura-Hata模型的各参数作为带约束条件的优化变量，以预测值与实测值的均方根误差和平均误差的加权和构造适应度函数，运用萤火虫算法进行优化实现Okumura-Hata模型在西安市区的本地化。在萤火虫算法中引入了“基因突变”和“优胜劣汰”操作，形成了一种改进型算法。基于大量实测数据的模型修正结果表明，所提方法可使电波损耗的预测值与实测值的均方根误差达到理论最小值9.585 9 dB，具有可行性。与基本萤火虫算法相比，改进的算法全局搜索能力更强，收敛速度更快。     

Do Jobseekers Value Diversity Information? Evidence from a Field Experiment and Human Capital Disclosures

We examine how information about the diversity of a potential employer's workforce affects individuals’ job-seeking behavior. We embed a field experiment in job recommendation emails from a leading career advice agency in the United States. The experimental treatment involves highlighting a diversity metric to jobseekers. Our results indicate that disclosing diversity scores in job postings leads jobseekers to click on firms with higher diversity scores, with such effects varying across jobseeker demographics. A follow-up survey provides evidence on potential explanations for why jobseekers value diversity information. We then examine how jobseekers’ preferences for diversity relate to disclosure choices under the U.S. SEC Human Capital Disclosure requirement. We find that firms in industries characterized by higher jobseeker responsiveness to diversity information tend to voluntarily disclose diversity metrics in their 10-Ks under these new disclosure requirements.     

Endogenous Growth,Skill Obsolescence,and Output Hysteresis in a New Keynesian Model with Unemployment

We embed skill obsolescence and endogenous growth into a New Keynesian model with search-and-matching frictions. The model accounts for key features of the Great Recession: the “productivity puzzle” and the “missing disinflation puzzle.” Lower aggregate demand raises long-term unemployment and the training costs associated with skill obsolescence. Lower aggregate employment hinders learning-by-doing, which slows down human capital accumulation, feeding back into even fewer vacancies than justified by the demand shock alone. These feedback channels mitigate the disinflationary effect of the demand shock while amplifying its contractionary effect on output. The temporary growth slowdown translates into output hysteresis.