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.     

数字经济对城乡居民收入差距影响研究——兼论城镇化的门槛效应

数字经济为缩小居民收入差距带来了新机遇,而“数字鸿沟”又可能引发新的贫富差距。研究数字经济对城乡居民收入差距的影响,对于认识和缩小差距,实现共同富裕具有重要意义。文章基于2011—2020年31个省域面板数据,通过构建静态、动态面板模型及门槛模型,分析数字经济对城乡居民收入差距的影响。研究发现:省域层面上,数字经济显著缩小城乡居民收入差距,且该影响具有单一门槛效应。在城镇化水平较低时,数字经济对城乡收入差距的影响不显著;当城镇化水平越过门槛值,数字经济水平显著影响城乡收入差距的缩小。异质性分析发现,我国南北地区呈现出不同的效应,北方省份城乡收入差距受数字经济水平影响较小,而南方较大。     

The ‘digital glimpse’ as imagining home

This paper proposes the concept of the ‘digital glimpse’, which develops the existing framing of imaginative travel. Here it articulates the experiences of mobile workers digitally connecting into family life and everyday rituals when physically absent with work. The recent embedding of digital communication technologies into personal relationships and family life is reconfiguring how absence is experienced and practiced by workers on the move, and through this, new digital paradigms for life on-the-move are emerging. This paper explores how such social relationships are maintained at-a-distance through digital technology – using evidence from qualitative interviews with mobile workers and their families. Digital technology now enables expressive forms of ‘virtual travel’, including video calling, picture sharing, and instant messaging. This has implications for the ways in which families can manage the social and relational pressures of being apart. Experiences of imaginative travel created through novel media can enrich the experience and give a greater sense of connection for both those who are at home and those who are away. While technology is limited in its ability to replicate a sense of co-presence, ‘digital glimpses’ are an emergent set of sociotechnical practices that can reduce the negative impact of absence on family relationships.     

Assistive technology for disabled visual artists: exploring the impact of digital technologies on artistic practice

Abstract

Disabled artists with physical impairments can experience significant barriers in producing creative work. Digital technologies offer alternative opportunities to support artistic practice, but there has been a lack of research investigating the impact of assistive digital tools in this context. This article explores the current practice of physically impaired visual artists and their experiences around the use of digital technologies. An online survey was conducted with professional disabled artists and followed up by face-to-face interviews with 10 invited artists. The findings illustrate the issues disabled artists experience in their practice and highlight how they are commonly using mainstream digital technologies as part of their practice. However, there is little awareness around novel forms of technology (e.g. eye gaze tracking) that present new creative opportunities. The importance of digital tools for supporting wider practice (i.e. administrative and business tasks) was also highlighted as a key area where further work is required.     

Influencing behaviour: The mindspace way

The ability to influence behaviour is central to many of the key policy challenges in areas such as health, finance and climate change. The usual route to behaviour change in economics and psychology has been to attempt to ‘change minds’ by influencing the way people think through information and incentives. There is, however, increasing evidence to suggest that ‘changing contexts’ by influencing the environments within which people act (in largely automatic ways) can have important effects on behaviour. We present a mnemonic, MINDSPACE, which gathers up the nine most robust effects that influence our behaviour in mostly automatic (rather than deliberate) ways. This framework is being used by policymakers as an accessible summary of the academic literature. To motivate further research and academic scrutiny, we provide some evidence of the effects in action and highlight some of the significant gaps in our knowledge.     

Sex, self-interest and health care priorities

In this questionnaire study, individuals were asked to prioritise publicly provided preventive health care services, one of which would be unavailable to them by virtue of their sex. The aim was to establish whether men and women would exhibit different degrees of self-interest when making a constrained choice. Around 1800 subjects from east-central England prioritised three different types of cancer screening. Most also provided written explanations for their rankings and these were classified into explanatory themes. Logistic regressions using socio-demographic and attitude data predicted the type of screening chosen as first priority. The analysis revealed that many men and women did indeed assign similar priorities to the different types of screening and, even when the priorities differed, these were often justified by similar arguments relating to technical aspects of the interventions and to self-interest. However, women were far more likely than men to prioritise a type of screening from which they themselves would benefit directly and the variations in preferences and explanations between the sexes occurred primarily because of differences in other-regarding attitudes. The bias towards screening of females was driven by women's greater worries about the disease in question and by men's “benevolent sexism” with respect to women's wellbeing.     

浅谈行动导向教学法在教学中的实践

主要以怠速控制阀的结构、原理及检测学习任务为例,阐述了如何在教学中实践以培养关键能力为核心的"行动导向教学法"。     

“We wouldn’t say it to their faces”: online harassment,women sports journalists,and feminism

In April 2016, a US-based independent sport media organization Just Not Sports launched #MoreThanMean, a digital media campaign to raise awareness about online harassment of women in sports journalism. The video quickly reached 3.7 million views and generated widespread coverage in mainstream news media, sports media, and online-only outlets. Using the #MoreThanMean campaign as a case study, this study assesses how discourses circulate in the sports media environment and, in particular, how feminist messages travel as the content moves from social media to mass media. This study engages with post-feminism in order to examine how various producers of media content position online harassment and sexism in sport and society. While the campaign positioned online harassment as gendered workplace discrimination, the mainstream and sports media coverage typically centralized men in the discussion. Feminist perspectives were constrained to platforms with a progressive, women-centered, and/or explicitly feminist take. Implications for digital feminist activism in the context of sport are discussed.     

数字经济发展的评估指标体系研究——基于投入产出视角

发展数字经济是我国重要国策,对其评估指标体系的研究受到多方关注,但目前我国数字经济测度仅仅局限于数字化产业和数字化创新,尚未形成一个完整、系统的数字经济评价指标体系。文章在引入治理环境的基础上,基于经济学上的投入产出视角探讨我国数字经济发展的有效测度方法,在研究数字经济的发展效应中新添了数字化治理和数字知识型人才供给两项指标,构建了一套基于投入产出视角的数字经济发展评价指标体系,为衡量数字经济发展提供了一个系统的体系。为提升数字治理现代化水平,更好发挥数字经济在促进经济高质量发展中的作用提供了实践意义和政策参考。     

A multicriteria sorting approach based on data envelopment analysis for R&D project selection problem

In this paper, multiple criteria sorting methods based on data envelopment analysis (DEA) are developed to evaluate research and development (R&D) projects. The weight intervals of the criteria are obtained from Interval Analytic Hierarchy Process and employed as the assurance region constraints of models. Based on data envelopment analysis, two threshold estimation models, and five assignment models are developed for sorting. In addition to sorting, these models also provide ranking of the projects. The developed approach and the well-known sorting method UTADIS are applied to a real case study to analyze the R&D projects proposed to a grant program executed by a government funding agency in 2009. A five level R&D project selection criteria hierarchy and an assisting point allocation guide are defined to measure and quantify the performance of the projects. In the case study, the developed methods are observed to be more stable than UTADIS.