Feature selection based on distance correlation: a filter algorithm

Feature selection (FS) is one of the most powerful techniques to cope with the curse of dimensionality. In the study, a new filter approach to feature selection based on distance correlation is presented (DCFS, for short), which keeps the model-free advantage without any pre-specified parameters. Our method consists of two steps: hard step (forward selection) and soft step (backward selection). In the hard step, two types of associations, between univariate feature and the classes and between group feature and the classes, are involved to pick out the most relevant features with respect to the target classes. Due to the strict screening condition in the first step, some of the useful features are likely removed. Therefore, in the soft step, a feature-relationship gain (like feature score) based on the distance correlation is introduced, which is concerned with five kinds of associations. We sort the feature gain values and implement the backward selection procedure until the errors stop declining. The simulation results show that our method becomes more competitive on several datasets compared with some of the representative feature selection methods based on several classification models.     

云南边疆少数民族间的"康吧"经济交往模式:理论与实证分析

"康吧"交往是纳西族与傈僳族、藏族之间一种独特而历史悠久的物质交换模式,它不符合理性选择的逻辑却能世代延续至今,同时,不同民族间的"康吧"交往又存在差异。本文借鉴西方主流理论对这种古老的交往模式进行分析,从经济学、社会学、人类学的多重理论角度出发,采用访谈、观察与定量分析相结合的研究方法,对上述现象进行了分析。研究结果表明:(1)资源依赖性、信任和互惠原则对"康吧"交往的延续至关重要;(2)货币市场和投机行为的出现导致"康吧"交往走向衰落,但情感互惠和资源互补使之至今存在;(3)自然资源条件、资源互补程度、社会历史背景和文化因素,对交往模式的差异都有重要影响作用。     

从多元系统论视角对儿童文学翻译的重新审视

从多元系统理论出发,将儿童文学翻译置于社会文化环境中考察,发现儿童文学处于文学系统的边缘。这种边缘位置导致儿童文学的翻译和创作受到了局限和压制,但是儿童文学系统和成人文学系统间模式的迁移和融合有利于产生一种新的成功模式。     

试论自然法思想在罗马法发展中的作用

罗马法之所以能跨越时空的限制,具有经久不衰的生命力,是与其中所蕴涵的自然法思想密不可分的。正是在自然法思想的指引下,罗马法才得以克服其自身的种种限制,步入良好而快速的发展轨道,并逐渐臻于完善。     

“拯救”新闻业的技术方案何以失灵?——区块链新闻初创公司“可感知创新属性”分析

区块链技术在范式创新的意义上激发了对新闻业前景的乐观想象,区块链新闻初创公司作为"颠覆性创新者",形成了与成熟媒体机构完全不同的创新路径。本文以创新扩散理论中的"可感知创新属性"为分析框架,考察了初创公司Civil的创新历程及其潜在采纳者在决策中可能感知的综合信息氛围。研究表明,Civil在商业和专业方面带来相对优势的感知是模糊的,甚至是高风险的;激进的创业文化与遵循制度化、常规化业务逻辑的传统新闻业存在相容性上的障碍;过于复杂的运行机制和购买流程大大降低了创新的可试验性和可观察性,这些因素共同构成了潜在采纳者对其创新属性的负面感知,进而使这种强调采纳决策相互依赖性的交互式创新趋于失败。     

论昆曲艺术在高校的传播

高校是继承和发展昆曲艺术的桥头堡,是培养昆曲观众的摇篮.文章认为,高校将戏曲艺术纳入公共艺术教育课程体系之中,是传播戏曲艺术、弘扬传统文化和培养戏曲观众的有效途径;充分利用多媒体等多种手段进行课堂教学,能增强大学生学习昆曲的兴趣;整合社会艺术资源,聘请戏曲专家和演员到学校兼职或举办专题讲座,是沟通昆曲艺术家和大学生的桥梁.     

Improved methods for moment restriction models with data combination and an application to two-sample instrumental variable estimation

Combining-100 information from multiple samples is often needed in biomedical and economic studies, but differences between these samples must be appropriately taken into account in the analysis of the combined data. We study the estimation for moment restriction models with data combined from two samples under an ignorability-type assumption while allowing for different marginal distributions of variables common to both samples. Suppose that an outcome regression (OR) model and a propensity score (PS) model are specified. By leveraging semi-parametric efficiency theory, we derive an augmented inverse probability-weighted (AIPW) estimator that is locally efficient and doubly robust with respect to these models. Furthermore, we develop calibrated regression and likelihood estimators that are not only locally efficient and doubly robust but also intrinsically efficient in achieving smaller variances than the AIPW estimator when the PS model is correctly specified but the OR model may be mispecified. As an important application, we study the two-sample instrumental variable problem and derive the corresponding estimators while allowing for incompatible distributions of variables common to the two samples. Finally, we provide a simulation study and an econometric application on public housing projects to demonstrate the superior performance of our improved estimators. The Canadian Journal of Statistics 48: 259–284; 2020 © 2019 Statistical Society of Canada     

相交线错觉因子及其在部分几何错觉中的作用

尽管目前人们已认识到视网膜成像模糊是产生某些视错觉的原因之一,但人们并不清楚它到底起着什么样的作用。本研究以相交线的模糊照片直接证明,相交线模糊成像时,其交点处发生了一系列变化。这使得由于光学及视网膜的结构特点的原因使视网膜的像上模糊,某些由相交线构成的几何错觉图形,实际上是类“拧绳”错觉图形。而另一些相交线构成的几何图形错觉,则直接包含了这些变化。这个结论本身还置关于这类错觉的侧抑制理论于次要地位,甚至完全被否定。     

HiTrapQ柱FPLC快速纯化人血清白蛋白(HSA)

为研制新型三、四天线半乳糖肝受体功能显像剂,须将三、四天线半乳糖与人血清白蛋白(HSA)偶联,故必须制备较纯净人血清白蛋白(HSA)。在FPLC上用HiTrapQ柱快速纯化人血清白蛋白(HSA)。经PAGE和SDS-PAGE鉴定只有一条带。在FPLC上用HiTrapQ柱纯化HSA有速度快、纯化量大且方法较为简便等特点。     

关于W.M.Davis地理循环论的数学分析和论证

本文先分析W.M.Davis地理循环论一直占地貌学基本理论统治地位的原因,然后根据地理循环论学说的假设条件和地貌学原理建立求分水高地平均高度a(t)、河谷低地平均高度b(t)等的曲线方程,从方程得出的曲线与有关地统学理论是一致的,从而从数学上论证地理循环模式的主要发展过程。