岷江上游干旱河谷区生态屏障体系建设研究

岷江流域是长江上游重要的支流,其生态地位特别重要,本文分析了岷江上游地区面临的基本生态问题,提出了岷江上游地区生态屏障体系建设的原则、依据与目标,根据岷江上游区域生态系统的空间特征、生态敏感性和生态系统服务功能,将该区域划分为三个生态功能区并确立了森林牧草、水域湿地、农田作物等生态屏障建设重点内容,切实有效维护该区域的生态经济可持续发展和资源环境的有效保护。     

面板数据的贝叶斯Elastic Net分位数回归方法及其应用研究

本文首次将Elastic Net这种用于高度相关变量的惩罚方法用于面板数据的贝叶斯分位数回归,并基于非对称Laplace先验分布推导所有参数的后验分布,进而构建Gibbs抽样。为了验证模型的有效性,本文将面板数据的贝叶斯Elastic Net分位数回归方法(BQR. EN)与面板数据的贝叶斯分位数回归方法(BQR)、面板数据的贝叶斯Lasso分位数回归方法(BLQR)、面板数据的贝叶斯自适应Lasso分位数回归方法(BALQR)进行了多种情形下的全方位比较,结果表明BQR. EN方法适用于具有高度相关性、数据维度很高和尖峰厚尾分布特征的数据。进一步地,本文就BQR. EN方法在不同扰动项假设、不同样本量的情形展开模拟比较,验证了新方法的稳健性和小样本特性。最后,本文选取互联网金融类上市公司经济增加值(EVA)作为实证研究对象,检验新方法在实际问题中的参数估计与变量选择能力,实证结果符合预期。     

审计师声誉作用机制研究--从审计需求的视角出发

审计师声誉是社会公众和利益相关者对于审计师的整体认知与评价,是审计服务质量的重要度量指标。从审计需求的两个基本理论--审计需求的代理理论和信息理论出发,分析审计师声誉的影响机理和作用路径。发现,审计需求会导致市场对审计师声誉的关注,高声誉的审计师可以限制机会主义行为,降低财务报告舞弊风险。进一步的分析表明：事务所的做大做强策略可以提升审计师声誉,而审计师声誉的提升不仅对完善审计市场的良好运行有决定性作用,还对整个资本市场的发展有显著的影响。     

Finie mixures of canonical fundamenal skew $$$$-disribuions

This paper introduces a finite mixture of canonical fundamental skew \(t\) (CFUST) distributions for a model-based approach to clustering where the clusters are asymmetric and possibly long-tailed (in: Lee and McLachlan, arXiv:1401.8182 [statME], 2014b). The family of CFUST distributions includes the restricted multivariate skew \(t\) and unrestricted multivariate skew \(t\) distributions as special cases. In recent years, a few versions of the multivariate skew \(t\) (MST) mixture model have been put forward, together with various EM-type algorithms for parameter estimation. These formulations adopted either a restricted or unrestricted characterization for their MST densities. In this paper, we examine a natural generalization of these developments, employing the CFUST distribution as the parametric family for the component distributions, and point out that the restricted and unrestricted characterizations can be unified under this general formulation. We show that an exact implementation of the EM algorithm can be achieved for the CFUST distribution and mixtures of this distribution, and present some new analytical results for a conditional expectation involved in the E-step.     

城乡医保一体化制度对农村居民就医行为的影响

本文利用Charls 2008-2012年两期数据,采用双重差分DID方法对城乡医保一体化制度的政策效果进行实证分析.研究表明:城乡医保一体化制度显著提高了农村居民过去一个月门诊次数和医疗费用;但在住院方面,目前尚无证据显示医保一体化政策对过去一年是否住院和最近一次住院费用有显著的影响.在考虑了样本损耗问题、户籍转换、政策非随机等问题后,本文结论依然稳健.     

Power analysis for clustered non-continuous responses in multicenter trials

Power analysis for multi-center randomized control trials is quite difficult to perform for non-continuous responses when site differences are modeled by random effects using the generalized linear mixed-effects model (GLMM). First, it is not possible to construct power functions analytically, because of the extreme complexity of the sampling distribution of parameter estimates. Second, Monte Carlo (MC) simulation, a popular option for estimating power for complex models, does not work within the current context because of a lack of methods and software packages that would provide reliable estimates for fitting such GLMMs. For example, even statistical packages from software giants like SAS do not provide reliable estimates at the time of writing. Another major limitation of MC simulation is the lengthy running time, especially for complex models such as GLMM, especially when estimating power for multiple scenarios of interest. We present a new approach to address such limitations. The proposed approach defines a marginal model to approximate the GLMM and estimates power without relying on MC simulation. The approach is illustrated with both real and simulated data, with the simulation study demonstrating good performance of the method.     

Variable selection in additive quantile regression using nonconcave penalty

This paper considers variable selection in additive quantile regression based on group smoothly clipped absolute deviation (gSCAD) penalty. Although shrinkage variable selection in additive models with least-squares loss has been well studied, quantile regression is sufficiently different from mean regression to deserve a separate treatment. It is shown that the gSCAD estimator can correctly identify the significant components and at the same time maintain the usual convergence rates in estimation. Simulation studies are used to illustrate our method.     

天津城市风貌塑造中的非物质要素传承

天津建卫六百年以来．社会文化的演变经历了数个重要过程．每个过程对天津城市风貌的塑造都起到了不同的作用。纵观这六百多年的城市建设历史不难发现．天津城市文化及核心价值观体现在如下几方面：     

突出生态历史保护科学开发滆湖

简要介绍了滆湖的历史、现状,针对其目前存在的4大类问题,提出了6项对策建议,突出强调了对滆湖应实行生态历史??切忌自然水域乡村开发的“城市化”倾向。     

简易程序的简化及其相对独立性特性研究

民事诉讼简易程序问题目前已成为法学专家、学者研究的热点话题,本文从简易程序中的起诉传唤方式、法庭审判程序、审判期限、判决书制作、调解和解相结合等方面进行仔细探讨,同时从简易程序的定位、简易程序的特殊性、简易程序的价值取向三方面对民事简易程序相对独立性特征进行研究,以确定民事简易程序的地位,使我们能够加深对民事简易程序的认识和理解。