网络原生传播的现实机理

互联网技术的飞速发展及其泛社会化应用,推动了网络原生传播从初期的小众现象发展为当今的大众化行为。基于传播类型的划分,网络原生传播主要体现在网络大众传播、群体传播与人内传播中,并各自具有独特的传播机制。同时,网络原生大众传播的浮光掠影、群体传播的封闭化与个体的双重困境,凸显出网络原生传播理性导向的三个维度:精神的沉淀与塑造、传播渠道的策略优化与对个体网络生存境况的人文观照。     

风险社会视域下“校园贷”问题的生成及应对

"校园贷"是一个横跨"在场空间"与"缺场空间"的"跨界性"问题,以风险社会理论为视角进行分析,可有效地贯通网上、网下两个空间的情境性区隔,是从整体上对其进行解读的理想选择。它的异变主要涉及社会急剧转型、网络技术发展及大学生群体结构三个风险源:社会转型过程中风险的无序释放是催生"校园贷"问题的现实动因,网络技术的风险特征是催生"校园贷"问题的潜在根源,大学生群体消费欲望强而财商低的结构特点是催生"校园贷"问题的重要因素。防范"校园贷"风险的关键在于建构政府主导、社会参与、个体自省的风险应对共同体,以减少各类风险发生交叠、共振的频率。     

社会网络分析视角下复杂网络结构关系的综合测度

为了克服复杂网络节点数量繁多、结构关系不易测度的难题,文章提出一种社会网络分析视角下“以点界面”的研究思路.通过构建一个新的综合测度指标,完成对网络中节点的综合评价,实现对网络结构关系的测度.与现有社会网络单一测度指标相比,综合测度指标突破现有单一测度指标的局限,构建过程充分利用单一测度指标间关系规律.复杂网络仿真实验进一步表明,无论有中心结构的网络结构和无中心结构的网络结构,综合测度指标提高网络节点不同评价维度和网络角色自带信息的利用率,对网络中节点的全面刻画更为贴切,为复杂网络结构关系综合测度研究提供一种新工具,为提高生活生产效率、预防灾害负面影响提供参考和依据.     

固定设计异方差非参数回归模型的预测方法

文章针对固定设计下异方差非参数回归模型,考虑了基于多项式样条的三种预测方法,即非外推法、线性外推法和非线性外推法.模拟结果表明非外推预测法的均方根误差(RMSE)和平均绝对误差(MAE)的均值最大,而线性外推法的RMSE和MAE的均值略小于非线性外推法的RMSE和MAE的均值.实证分析结果显示:非外推预测法的平均绝对百分比误差(MAPE)、RMSE和MAE最大,线性外推法的MAPE、RMSE和MAE最小.这表明整体上外推法优于非外推法,而线性外推法是简单可行的.     

Testing homogeneity in semiparametric mixture case–control models

Parametric and semiparametric mixture models have been widely used in applications from many areas, and it is often of interest to test the homogeneity in these models. However, hypothesis testing is non standard due to the fact that several regularity conditions do not hold under the null hypothesis. We consider a semiparametric mixture case–control model, in the sense that the density ratio of two distributions is assumed to be of an exponential form, while the baseline density is unspecified. This model was first considered by Qin and Liang (2011 Qin, J., Liang, K.Y. (2011). Hypothesis testing in a mixture case–control model. Biometrics 67(1):182–198.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar], biometrics), and they proposed a modified score statistic for testing homogeneity. In this article, we consider alternative testing procedures based on supremum statistics, which could improve power against certain types of alternatives. We demonstrate the connection and comparison among the proposed and existing approaches. In addition, we provide a unified theoretical justification of the supremum test and other existing test statistics from an empirical likelihood perspective. The finite-sample performance of the supremum test statistics was evaluated in simulation studies.     

基于贝叶斯学习的惩罚因子的选择

文章基于贝叶斯学习,将正则化方法从贝叶斯分析的角度展开,在响应变量服从正态分布、回归系数服从指数型先验分布族的条件下,用贝叶斯准则给出了惩罚因子的取值与响应变量、系数的方差之间的关系,并将这一结果应用到岭回归和lasso回归中惩罚因子的选择.实例检验结果表明,当响应变量和系数服从正态分布,惩罚因子的值取二者方差商的方法比岭迹法和广义交叉验证法(GCV)拟合效果更优.     

北京金融"怎么看?""怎么办?"

以习近平总书记视察北京为标志,北京的城市功能定位和发展战略方向得到了明确,北京整个城市正在重新出发.作为北京第一大支柱产业,金融业的重新出发已刻不容缓.通过对北京金融业的雄厚基础、 得天独厚的发展优势、 北京金融业实现转型发展存在的短板进行梳理和分析,提出建设"首都型金融"的新目标和近期推动"首都型金融"发展的重点任务.     

Parameter estimation of a composite production function model based on improved artificial fish swarm algorithm and model application

The traditional Cobb–Douglas production function uses the compact mathematical form to describe the relationship between the production results and production factors in the production technology process. However, in macro-economic production, multi-structured production exists universally. In order to better demonstrate such input–output relation, a composite production function model is proposed in this article. In aspect of model parameter estimation, artificial fish swarm algorithm is applied. The algorithm has satisfactory performance in overcoming local extreme value and acquiring global extreme value. Moreover, realization of the algorithm does not need the gradient value of the objective function. For this reason, it is adaptive to searching space. Through the improved artificial fish swarm algorithm, convergence rate and precision are both considerably improved. In aspect of model application, the composite production function model is mainly used to calculate economic growth factor contribution rate. In this article, a relatively more accurate calculating method is proposed. In the end, empirical analysis on economic growth contribution rate of China is implemented.     

The heterogeneous impact of pension income on elderly living arrangements: evidence from China’s new rural pension scheme

This paper investigates the impact of pension income on living arrangements of the elderly. Taking advantage of a unique opportunity due to the recent establishment and expansion of the New Rural Pension Scheme in China, we explicitly address the endogeneity of pension status and pension income through a fixed-effect model with instrumental variable approach by exploiting exogenous time variation in the program implementation at county level. We find an overall positive effect of pension income on independent living as well as considerable heterogeneity. The positive income effects of the NRPS are concentrated among the elderly with adult children living nearby, of higher socio-economic status, and with better health at baseline; for other groups, the effects are insignificant. We also find that more generous programs exhibit larger effects. Our results highlight that living arrangement is multidimensional in rural China.     

贝叶斯方法和频率方法比较研究

频率学派和贝叶斯学派作为统计推理中的两个最重要的方法,对于这两种对立的研究方式的站队选择显然影响着研究者的研究活动。占有霸主地位的频率学派尽管是后来者,显然占有着优势的地位,而今年以来贝叶斯方法的复苏,重新向频率派发起挑战。文章从概率的产生作为开始,简单地介绍了统计的发展历程,并分别对这两种方法选择的实用、重要的可操作标准给予分析,认为两种方法各有利弊,对两种方法的选择应结合实际情况选择。