An elastic-net penalized expectile regression with applications

To perform variable selection in expectile regression, we introduce the elastic-net penalty into expectile regression and propose an elastic-net penalized expectile regression (ER-EN) model. We then adopt the semismooth Newton coordinate descent (SNCD) algorithm to solve the proposed ER-EN model in high-dimensional settings. The advantages of ER-EN model are illustrated via extensive Monte Carlo simulations. The numerical results show that the ER-EN model outperforms the elastic-net penalized least squares regression (LSR-EN), the elastic-net penalized Huber regression (HR-EN), the elastic-net penalized quantile regression (QR-EN) and conventional expectile regression (ER) in terms of variable selection and predictive ability, especially for asymmetric distributions. We also apply the ER-EN model to two real-world applications: relative location of CT slices on the axial axis and metabolism of tacrolimus (Tac) drug. Empirical results also demonstrate the superiority of the ER-EN model.     

Quantile regression for large-scale data via sparse exponential transform method

In recent decades, quantile regression has received much more attention from academics and practitioners. However, most of existing computational algorithms are only effective for small or moderate size problems. They cannot solve quantile regression with large-scale data reliably and efficiently. To this end, we propose a new algorithm to implement quantile regression on large-scale data using the sparse exponential transform (SET) method. This algorithm mainly constructs a well-conditioned basis and a sampling matrix to reduce the number of observations. It then solves a quantile regression problem on this reduced matrix and obtains an approximate solution. Through simulation studies and empirical analysis of a 5% sample of the US 2000 Census data, we demonstrate efficiency of the SET-based algorithm. Numerical results indicate that our new algorithm is effective in terms of computation time and performs well for large-scale quantile regression.     

Cox regression of clustered event times with covariates missing not at random

Motivated by a recent tuberculosis (TB) study, this paper is concerned with covariates missing not at random (MNAR) and models the potential intracluster correlation by a frailty. We consider the regression analysis of right‐censored event times from clustered subjects under a Cox proportional hazards frailty model and present the semiparametric maximum likelihood estimator (SPMLE) of the model parameters. An easy‐to‐implement pseudo‐SPMLE is then proposed to accommodate more realistic situations using readily available supplementary information on the missing covariates. Algorithms are provided to compute the estimators and their consistent variance estimators. We demonstrate that both the SPMLE and the pseudo‐SPMLE are consistent and asymptotically normal by the arguments based on the theory of modern empirical processes. The proposed approach is examined numerically via simulation and illustrated with an analysis of the motivating TB study data.     

大学生课堂使用手机的实证研究 ——基于南充市三所高校的调查

大学生课堂上玩手机已成为较为普遍的现象。通过对南充三所高校750名大学生进行实证研究,了解大学生课堂使用 手机的频率、不同课程类型使用率、态度等,分析其原因,揭示大学生使用手机给课堂带来的双面影响,在此基础上提出针对性 措施：引导学生进行正确的自我归因,增强主动性;课堂管理松弛有度,实施必要的教学改革;发挥智能手机辅助教学的作用。     

农户家庭人力资本存量与家庭收入关系分析——以山西农户为例

根据山西省农村跟踪观察户资料，通过对农户家庭人力资本存量与家庭收入水平之间关系的实证分析，结果表明：户主为初中文化程度的家庭，户均纯收入由最高变化为低于高中户，而后依次为小学户和文盲半文盲户；农户家庭劳动力平均受教育水平越高，户均纯收入也越高，且随着家庭综合教育水平的提高，教育投资的收入弹性呈递增趋势；接受职业教育和技术培训的农户家庭，其户均纯收入、经营性收入、总收入均高于未接受者，家庭中接受培训的劳动力数量越多，家庭收入越高。     

政府不合理税费政策对企业行为的影响及对策

政府不合理的税费政策主要表现在税负过重、税负不公、税外收费过多等三个方面。政府不合理的税费政策对企业的战略制定、价格形成、产品质量等无不产生着极为不利的影响。为此,一是要适应经济增长水平,确定合理的企业总体负担水平;二是要适应加入世贸组织的要求,尽快规范税收优惠政策,统一税制,公平税负;三是要下定决心,令行禁止,有计划地实施“费改税”工程。     

我国中小金融机构的生存与发展空间

我国中小金融机构虽然目前面临着种种困难与挑战,但仍然有着广阔的发展空间与机遇.面对广大中小企业及农民巨大而迫切的资金需求,国有银行等大银行因信息不对称、交易成本过高及所有制障碍而无法给予满足.而中小金融机构因具有与中小企业所有制上的一致性、地域上的一体性及自身产权的明晰性等特点,使其在对中小企业的信贷服务中具有信息优势、成本优势及管理优势,加上政府及有关方面的政策扶持,就使它们有能力去实际占领这一空间.     

改革是一场新的革命——纪念党的十一届三中全会召开20周年

邓小平关于改革的理论是新时代的新创举,是对科学社会主义的伟大贡献,“改革是中国的第二次革命”的科学论断是对马克思主义理论和中国革命实践相结合的新发展,对解放和发展生产力,建设中国特色社会主义具有非常重要的理论指导意义。本文围绕回顾我国社会生产力的发展和改革历程以及完善和建立社会主义市场经济新体制     

历史文化名城武威旅游资源定量评价

在实地考察和分析数据的基础上 ,运用层次分析法和模糊数学法对武威市旅游资源进行了定量评价 ,得到旅游资源各评价因子的权重、分值及综合评分值 ,并对其进行等级划分 ,为武威旅游业的发展提供了基础资料和依据。     

市场结构与我国茶叶国际竞争力的研究

首先运用市场结构理论分析了不同市场结构下市场主体的不同行为特征，在此基础上对茶叶国际市场结构以及我国在茶叶国际市场中的地位进行分析，并据此得出我国在茶叶出口市场中应采取的合理行为以及国内茶叶出口企业应进行的行为组织方式变革.