基于高维波动率网络模型的股票市场风险特征研究

波动率是金融风险管理研究的重要内容之一。本文基于复杂网络理论和数据挖掘技术提出股票市场的高维波动率网络模型。首先运用互信息度量不同股票价格波动之间的相关关系,其次对股票市场不同周期下的波动情况建立度的中心势、平均距离、幂律分布等网络拓扑指标,再次根据这些指标利用Prim算法构建出高维波动率网络模型,最后运用Newman-Girvan算法对股票价格波动率的相关性进行分层研究。高维波动率网络模型突破了传统波动率模型关于变量维数的限制,能够在依赖少量假设的基础上,挖掘出多个金融市场主体间的相互关系,反映金融市场的风险特征及网络拓扑性质。实证结果发现：与常用的Pearson相关系数法相比,在互信息框架下,股价波动的非线性相关关系得到了更好的度量;股票市场的整体波动性与个股波动率相关性变化趋势相反,市场处在高波动时期资产组合分散化效果较好;网络中存在少量度数大的关键节点和中心节点,风险通过这些节点可以迅速传递到整个市场;股票市场的运行具有明显的行业聚集现象;网络分层研究进一步直观的展现了风险在层与层之间的传递规律和与之对应的行业特征。高维波动率网络模型为挖掘股票市场的风险特征与管理金融风险提供了一个新的工具。     

DEVIL'S ADVOCACY AND DIALECTICAL INQUIRY EFFECTS ON PREDICTION PERFORMANCE: TASK INVOLVEMENT AS A MEDIATING VARIABLE

Critics of previous laboratory experiments comparing devil's advocacy (DA) to dialectical inquiry (DI) have suggested that these experiments produced misleading results because (1) they used subjects who had low levels of task involvement and (2) the DI treatment used was confusing to subjects and required further explanation to be useful. The present study examines the effects of four inquiry methods—expert (E), DA, DI, and DI with explanatory statement (DI+)—on subjects' performance at a financial prediction task. Results show that DA, DI, and DI + were superior to E when the state of the world differed significantly from assumptions underlying the expert's plan. For subjects with high task involvement, DI and DI + were more effective than E and DA. The results support some of the criticisms of previous laboratory research and suggest that future research on these decision aids should include task involvement as a factor.     

应用型本科电气信息类专业的实践性教学研究

电气信息类专业具有多学科有机融合的特点，应用型本科电气信息类专业面向生产实际和工程技术开发培养具有较强实践能力和一定创新精神的高级工程技术人才，专业的实践性教学十分重要。德国大学(Uni)和高等专业学院(Fachhochschule)电气信息类专业的实践性教学包括课程练习、实验、工业实践训练、项目研究、毕业论文等形式，形成了完整的体系。与德国相比，我国应用型本科电气信息类专业的实践性教学体系尚在形成之中。独立开设实验课、加强基础实验、开发综合性实验、现场实习、建设校内实践教学基地以充分利用仿真技术是应用型本科电气信息类专业加强实践性教学的有效途径。     

Informatization, voter turnout and income inequality

In recent years, voter turnout has been decreasing in most industrial countries, and about 40% of all electors abstain from voting. This may affect income inequality and the GDP growth rate through a redistribution policy determined by majority voting. In this paper, we explore the reasons for this continuing decrease in voter turnout and assess its social costs. We conclude that informatization lowers voter turnout by generating an information overload, and that a decrease in voter turnout lowers GDP growth by limiting income redistribution.      

Some Cautions on the Measurement of User Information Satisfaction*

User information satisfaction (UIS) is important because of its potential effects on MIS department goals, quality of user work life, and extent of voluntary usage of systems. Reliable measurement of UIS is important for providing evaluative information for both researchers and practitioners. This study used 92 managers and executives as subjects to compare the test/retest reliability of a widely used, 13-scale UIS instrument together with four summary questions under experimental and control conditions. The summary questions behaved more reliably than the detailed questions for all groups, perhaps because of problems with scale units and origins and with item heterogeneity. This suggests that researchers need more reliable measures of UIS and that practitioners need to exercise caution when collecting and interpreting UIS scores.     

An examination of the role of online social media in journalists’ source mix

Using telephone surveys of business/financial journalists in the United States (n = 200), this research investigates the agenda-building role of social media content in journalists’ work. Understanding that more non-public relations content from user-generated and social network sites, like YouTube and Twitter, are fast becoming resources for journalists to get story ideas, break scandals, and find sources, we began this scholarly work to determine the frequency of such uses of social media. Overall, findings indicate very little use of social media by these business journalists. Results and implications for public relations practitioners are discussed in detail.     

面向未来的埃及教育改革

埃及实行免费教育体制,长期和持续的国家投入保证了教育在大众中间的普及,使埃及教育长期在阿拉伯国家和非洲地区处于领先地位。但随着全球化的日益深入以及埃及国内经济形势的变化,单纯依靠政府投入越来越不能满足人民群众对高质量教育服务的需求。埃及教育主管部门根据形势发展的迫切要求,一方面大力推进教育体制改革,力行非中央化的政策,在教育投入和管理上,加大社会力量参与的力度,加强了教育基础设施建设,提高了教师待遇;另一方面用先进的信息技术手段改造传统教育模式,并在教学过程中引入问责制度,保证教育质量不断提高,使其更好地服务于社会经济的发展。     

The bivariate alpha-skew-normal distribution

In this paper, we propose a new bivariate distribution, namely bivariate alpha-skew-normal distribution. The proposed distribution is very flexible and capable of generalizing the univariate alpha-skew-normal distribution as its marginal component distributions; it features a probability density function with up to two modes and has the bivariate normal distribution as a special case. The joint moment generating function as well as the main moments are provided. Inference is based on a usual maximum-likelihood estimation approach. The asymptotic properties of the maximum-likelihood estimates are verified in light of a simulation study. The usefulness of the new model is illustrated in a real benchmark data.     

The effects of information form and domain-specific knowledge on choice deferral

Three studies examined the effect of information form on choice deferral in consumer choice and explored the moderating role of knowledge about the product domain. Two theoretical approaches were contrasted: (1) The process approach predicting that choice deferral varies as a function of information form, and (2) the communication approach predicting an interaction of information form and domain-specific knowledge. Participants were presented with different laptops described in an absolute (e.g. ‘300 GB hard disc’), evaluative-numerical (e.g. ‘hard disc with 30 out of 100 points in an expert rating’) or evaluative-verbal (e.g. ‘bad hard disc’) information form, and they could choose to buy one of the laptops or defer. Domain-specific knowledge was also assessed. In Study 1, evaluative-numerical and evaluative-verbal values led to more deferral in people with high domain-specific knowledge. The pattern for evaluative-numerical and evaluative-verbal values was replicated for a different information organization in Study 2. Study 3 showed that absolute values led to more deferral the less knowledgeable participants were and demonstrated that domain-specific knowledge and deferral were unrelated when absolute and evaluative-verbal values were presented in combination. In sum, the results support the communication approach and have methodological implications for decision research and theoretical implications for understanding choice deferral in real-life decisions.     

青少年学业压力、父母支持与精神健康

追求学业上的成就,并由此实现社会流动、赢得尊敬和家庭的荣耀是中国文化的传统。但对教育成就的重视也导致儿童承受很大的压力,引发心理和身体的疾病。对上海685名学生学业压力与精神健康的调查证实,学业压力是加剧学生焦虑的风险因素,而父母的情感支持是促进儿童精神健康的保护性因素。因此促进父母对儿童的学习参与是重要的,但要注意时机,动态了解儿童的学习压力状况并提供及时的情感支持,这样有助于儿童的精神健康。