自我网络特征对电信客户流失的影响

近年来，随着移动通信行业的蓬勃发展，市场饱和度越来越高，企业获取新用户的成本也越来越大。随着中国三大运营商竞争的加剧，产品和服务的同质化程度也越来越高，这使企业在老客户的保留上变得异常困难，客户流失率也在逐年上升，如何识别高风险流失客户并有效防止客户流失已经成为该行业管理者普遍关心的问题之一。 着眼于客户流失影响因素研究，运用社交网络分析方法，通过构造与网络结构相关的变量进行影响因素的探讨，运用逻辑回归方法构建客户流失预警模型。从社交网络的视角出发，利用客户的通话详单数据建立客户之间的通信网络，在自我网络的相关理论框架下，构建个体的度、联系强度、个体的信息熵3个自我网络特征变量。运用中国某移动运营商公司的月度客户数据(包括基础通信数据和通话详单数据)，通过逻辑回归构建基于社交网络变量的客户流失预警模型。 研究结果表明，个体的度、联系的强度和个体的信息熵都对预测客户流失有显著效果。具体的，个体的度越大，联系强度越强，个体的信息熵越大，客户越不容易流失。外样本AUC值平均可以达到0.75以上，模型具有良好的预测精度。 研究结果对企业实践具有非常重要的意义，合作企业应用客户流失预警模型进行高风险流失客户的识别，预测精度可以达到70%，达到了企业的实践预期。客户流失预警模型可以帮助企业提前识别高风险流失客户，极大地降低企业维系客户的成本。建议企业管理者在未来更加关注与客户社交网络有关的变量，从网络结构的视角理解消费者行为，更好地进行客户关系管理。     

基于双因子的公平偏好模型研究

基本公平偏好模型虽然能较好地解释现实中存在的“投桃报李”等互惠互利现象,但却忽略了这样一个基础问题:这种“公平”比较的基点本身是否满足“公平性”.文章通过对基本公平偏好模型的修正,构建了双因子收入公平偏好模型,从而弥补和修正了原有模型中存在的基础假设缺失的难题.由双因子模型可得结论:双因子呈反向变化关系;双因子放大了净收入变化所带来的效用改变程度.其研究的意义在于:双因子模型能够解释基本公平偏好所不能解释的一些激励问题;定量说明了交易中委托方应当如何根据代理方双因子的特征(而非仅依据公平偏好单因子),提供合理收益分配方案,以促进合作成功.     

Bayesian quantile regression for parametric nonlinear mixed effects models

We propose quantile regression (QR) in the Bayesian framework for a class of nonlinear mixed effects models with a known, parametric model form for longitudinal data. Estimation of the regression quantiles is based on a likelihood-based approach using the asymmetric Laplace density. Posterior computations are carried out via Gibbs sampling and the adaptive rejection Metropolis algorithm. To assess the performance of the Bayesian QR estimator, we compare it with the mean regression estimator using real and simulated data. Results show that the Bayesian QR estimator provides a fuller examination of the shape of the conditional distribution of the response variable. Our approach is proposed for parametric nonlinear mixed effects models, and therefore may not be generalized to models without a given model form.     

分段启动压力对宝浪油田驱动压差的影响

摘要：渗透率低于 10 mD 的特低渗储层与平均渗透率大于 20 mD 的低渗储层开发技术政策界限和开发方案制定等有很大的差别，渗透率越低，其启动压力成倍增加，这就影响了开发技术和方案的制定。应用分段启动压力梯度进行分段计算并进行对比，计算结果表明：用同一启动压力梯度计算的结果不符合实际情况，而应用分段启动压力梯度计算的结果更能很好地反映特低渗储层的实际情况；井距对较高渗透率的驱动压力计算影响并不大，但对于特低渗储层的驱动压力计算则影响很大。     

Symmetrical design for symmetrical global sensitivity analysis of model output

Symmetrical global sensitivity analysis (SGSA) can help practitioners focusing on the symmetrical terms of inputs whose uncertainties have an impact on the model output, which allows reducing the complexity of the model. However, there remains the challenging problem of finding an efficient method to get symmetrical global sensitivity indices (SGSI) when the functional form of the symmetrical terms is unknown, including numerical and non-parametric situations. In this study, we propose a novel sampling plan, called symmetrical design, for SGSA. As a preliminary experiment for model feature extracting, such plan offers the virtue of run-size economy due to its closure respective to the given group. Using the design, we give estimation methods of SGSI as well as their asymptotic properties respectively for numerical model and non-parametrical model directly by the model outputs, and further propose a significance test for SGSI in non-parametric situation. A case study for a benchmark of GSA and a real data analysis show the effectiveness of the proposed design.     

Interval-valued data regression using partial linear model

Semi-parametric modelling of interval-valued data is of great practical importance, as exampled by applications in economic and financial data analysis. We propose a flexible semi-parametric modelling of interval-valued data by integrating the partial linear regression model based on the Center & Range method, and investigate its estimation procedure. Furthermore, we introduce a test statistic that allows one to decide between a parametric linear model and a semi-parametric model, and approximate its null asymptotic distribution based on wild Bootstrap method to obtain the critical values. Extensive simulation studies are carried out to evaluate the performance of the proposed methodology and the new test. Moreover, several empirical data sets are analysed to document its practical applications.     

基于最近邻分析的空气质量时空数据异常点识别

空气质量数据具有在时间上连续、空间上相关的特点,这提高了异常点识别的难度.本文提出在时间维度上运用移动平均法,在空间维度上运用反距离加权法对观测值进行预测并求残差的解决思路,从而将时空数据的异常点识别问题转化为二维残差值的异常点检测问题.通过仿真验证表明新方法具有良好的检出力.最后将新方法应用于北京市实际观测数据,取得了满意的识别效果.     

论近年来“长城小说”题材内容的新变

重点关注了《王白的长城》、《湖光山色》等几部"长城反思小说"与"长城乡土小说",通过叙事形态变化和社会价值变化两个层面,论述了近年来"长城小说"题材内容的变化。在叙事形态上近年来有关长城的反思小说和乡土小说引人关注;而在社会价值方面长城小说呼唤"生态意识"、"家园意识"的回归,引发了人们对环境的忧虑以及对古长城开发与保护的深思。     

加入WTO与中国社会保障制度的发展与完善

十年来中国社会保障建设取得了很大的成就,社会保障成为改善民生和社会建设重要领域和促进力量,对于克服经济全球化深入发展背景下各种矛盾、促进经济发展和社会稳定发挥着积极的作用。但是,中国社会保障制度还不完善,面对世界贸易组织框架下越来越复杂的国际国内形势,需要进一步加快社会保障制度建设,选择科学合理的社会保障模式和管理体制,加强社会保障公共服务体系建设,实现人人享有社会保障。     

Barriers to Managing Coronary Artery Disease Among Older Women

Numerous barriers to managing coronary artery disease (CAD) among older women are reported in the literature; however, few studies adjust for demographic and health status differences. A survey assessing barriers and other factors was distributed to a stratified random sampling of older women with CAD. Factor analysis and multiple logistic regression procedures were used to estimate the impact of these issues on receiving a CAD-related office visit. The most problematic barriers included denial and low health literacy. Efforts to promote patient awareness of heart health and better communication between patients and clinicians may alleviate these barriers.