Variance estimation based on blocked 3×2 cross-validation in high-dimensional linear regression

In high-dimensional linear regression, the dimension of variables is always greater than the sample size. In this situation, the traditional variance estimation technique based on ordinary least squares constantly exhibits a high bias even under sparsity assumption. One of the major reasons is the high spurious correlation between unobserved realized noise and several predictors. To alleviate this problem, a refitted cross-validation (RCV) method has been proposed in the literature. However, for a complicated model, the RCV exhibits a lower probability that the selected model includes the true model in case of finite samples. This phenomenon may easily result in a large bias of variance estimation. Thus, a model selection method based on the ranks of the frequency of occurrences in six votes from a blocked 3×2 cross-validation is proposed in this study. The proposed method has a considerably larger probability of including the true model in practice than the RCV method. The variance estimation obtained using the model selected by the proposed method also shows a lower bias and a smaller variance. Furthermore, theoretical analysis proves the asymptotic normality property of the proposed variance estimation.     

论行政法律解释

行政法律解释是行政主体以适用行政法为目的,对行政法律规范的含义进行探求和说明的活动。行政解释权的限度就是依法行政原则。在当前中国,依法行政的第一涵义就是无授权即无行政。行政解释的对象是行政法律规范。文法解释是一切行政解释的基础;体系解释是文法解释之后必须首先运用的解释;法意解释和目的解释是体系解释之后的解释选择方法。必须综合利用各种解释方法以获得合理的解释结果,从而贯彻合法性及正义信念。     

新时期中国-伊朗关系的战略定位分析

本文简要概括了中国、伊朗建交以后两国关系的发展历程,认为中伊关系经历了四个阶段的曲折演变,在此基础上进一步分析了中伊关系对中国在中东地区的大国话语权、能源安全战略、经贸和投资战略、对伊斯兰世界影响力和中美关系博弈的重要影响,最后对中伊关系的未来发展战略定位进行了分析.     

对青少年病态追星的探讨

病态追星指的是由于个体过度爱慕、追求和崇拜明星而产生的对明星的特殊嗜好，并使自身生理、心理和社会受到损害的一种现象．具体表现为成瘾者毫无节制地终日沉溺于对明星的关注和幻想之中，并由此而产生身心依赖现象。来自明星的吸引力、青少年自身的推动力和外界环境的影响力是造成青少年病态追星的主要因素。它们相互渗透、共同作用，在其“合力”作用下，极易导致一些青少年病态追星。本文在分析青少年病态追星的思路上有其创新之处。     

青少年追星行为的误区:对娱乐明星的人格崇拜

青少年追星的非理性行为表现为偶像被曝丑闻后仍迁就之、不顾后果地追捧偶像、为了引起偶像的注意而不择手段等,其根源在于青少年对偶像的人格崇拜。明星对社会展示着技能形象和道德形象,民众对明星的信赖分为技能欣赏和人格崇拜两个阶段。明星的虚假道德形象起因于其刻意把自己"打造"为道德榜样、独特的"成名"路径等。青少年追星族应该警醒偶像可能在人格方面并不完美,在追星时应保持自身的人格独立。     

对扶贫贴息贷款和扶贫互助资金的比较研究——基于新制度经济学视角

政府主导的信贷扶贫模式三十年来在发展中不断变革,扶贫贴息贷款和扶贫互助资金分别是维持时间最长和最新兴的两种模式.从新制度经济学相关理论出发,按照“组织一行为一绩效”的研究范式对二者的内涵和特点进行比较分析,可以发现,制度设计不同导致了二者资金使用效率迥异,应考虑在二者间建立垂直型金融联结.     

The effects of landscape scale on greenery and traffic relationships with urban birds and butterflies

Actions and policies to enhance biodiversity in the urban landscape must match the spatial scale at which biodiversity responds to the management and target variables. To this end, we compare the importance and effect of different kinds of greenery cover and road-lane density on bird and butterfly species richness between two landscape scales: 50-m versus 126-m radii around point counts (equivalent to areas of 0.8 h and 5 ha, respectively). We also compared the results against those of an earlier study using 500-m walking transects with widths of 100 m (i.e., 5 ha). Road lane density was more important at the 126-m than 50-m radius for both birds and butterflies. For birds, natural vegetation or forest cover and cultivated shrub cover were also more important at 126-m radius whereas the cultivated tree canopy cover was more important at 50-m radius. Cultivated tree cover and natural vegetation or forest cover were positively associated with species richness while road lane density and cultivated shrub cover were negatively associated with species richness. The results from point counts generally corroborate the results from the transects-based study, except that the short-duration point counts performed poorly in sampling butterflies. Our results indicate that in designing urban greenery policy, the plot sizes of individual developments is an appropriate spatial scale for the stipulation of tree cover targets, while urban planners have more flexibility to allocate natural greenery at broader spatial scales.

     

试析墨家的"语义悖论"思想

在悖论发展的两千多年的历史中,人类发现和构造了各种类型的悖论,其中"语义悖论"是最原始的类型,同时也是当代悖论研究中最重要的内容.无论在古希腊、古印度还是中国的先秦,都曾产生过"语义悖论"思想.当代中国研究悖论的学者认为《墨经》中的悖论是"半截子悖论",而非严格悖论.墨家辩学的实用目的性和墨家重语义轻语形的语言哲学观是"半截子悖论"产生的主要原因.     

论我国海事侵权及船舶碰撞的法律适用——兼论我国《海商法》第273条的不足和完善

海事侵权是民事侵权的一个重要组成部分,我国《海商法》第273条仅对船舶碰撞的法律适用做了专门规定,但是缺乏对一般海事侵权的规定,在有关海事侵权的立法规定上存在着明显的缺陷。作者在分析几种常见的海上侵权及法律适用原则和比较主要航运国家有关海事侵权法律适用的立法及相关的国际公约的基础上,分析了我国现行《海商法》的立法缺陷,提出了完善我国《海商法》有关海事侵权及船舶碰撞法律适用的立法建议。     

拟声词与"一声/一下V"的组配关系

“拟声词＋一声／一下Ｖ”结构中的拟声词可分为只能与　“一声”组配的甲类，既可与“一声”又可与“一下”组配的乙类，只能与“一下”组配的　丙类；动词可分为发声动词、联声动词、伴声动词、绘声动词、无声动词五类。它们之间的　组配具有选择性。拟声词与“一声／一下Ｖ”组配后具有了强烈的动态性和明显的结果性等整　体意义。由于组配方式和要素的不同，形成了从单纯表示声响动态到单纯表示视觉动态的意　义变化系列。