基于视觉传感的焊缝跟踪系统研究现状

视觉传感技术在焊接机器人上的应用,大大提高了机器人的焊接效率和焊接质量。文中介绍了基于视觉传感的 焊缝跟踪系统的分类及主动视觉和被动视觉技术的基本原理;分析了图像处理技术的滤波去噪、图像分割与边缘检测和 特征分析等研究方法;分析了焊缝跟踪系统的控制结构和智能控制技术的应用现状。最后提出根据视觉传感系统测得 焊缝的信息,实时调节焊接参数以及焊枪角度等工艺参数进行自动化和智能化焊接是未来发展方向。     

外部视觉情绪设计对多媒体学习的影响

以高中生为被试对象,以大陆漂移论为素材,研究外部视觉情绪设计对多媒体学习的影响。结果表明,接受情绪设计组(实验组)的积极情绪显著高于中性组(对照组);实验组与对照组内在认知负荷、相关认知负荷均无显著差异,外在认知负荷小于对照组;实验组保持测验成绩显著高于对照组,迁移测验成绩无差异。同时,外部视觉情绪设计能显著提高多媒体学习效果。外部视觉情绪设计的实验设计突破了已有研究300s学习素材的诱发时间,拓展了多媒体学习情绪设计的内涵。     

近三十年藏戏研究的发展脉络与趋势——基于计量可视化分析

藏戏被誉为藏文化“活化石”,分别于2006年和2009年被列入国家和世界非物质文化遗产目录。近年来,随着国家大力提倡非物质文化遗产保护和优秀中华文化“走出去”,藏戏研究也日益成为学界关注热点。为了厘清藏戏研究现状,研究热点与趋势,本研究通过CiteSpace与VOSviewer两个主流计量可视化分析软件对国内近三十年藏戏研究成果进行较为详尽的分析,以期为进一步推动藏戏创新研究提供基础数据支撑。直观的可视化分析结果表明：目前藏戏研究处于缓慢发展阶段,但研究内容逐渐向多元化、跨学科方向发展。藏戏研究的核心作者和机构较少,且合作关系不明显。如何服务公共文化体系和非物质文化遗产的传承是目前藏戏研究最新主题。藏戏内涵的丰富性,未来势必会吸引更多学科专家从不同视角对藏戏的传承和保护进行研究。     

论新世纪武侠电影视觉中心的美学取向

新世纪武侠电影注重影像造型,更多挖掘电影的视听元素,充分调动色彩和道具的作用,选取极度唯美的场景,运用数字化特技设计的武打场面,表现了视觉中心的关学取向。客观上说,这对于吸引观众对武侠片的热情起到了一定的积极作用。但以视觉快感为导向的创作倾向,也在某种程度上导致了有些电影的晦涩难解,影响武侠电影中侠文化的弘扬,从而导致人文关怀和人文精神的匮乏。     

C2C网上交易中信号机制的有效性分析

本文应用Berry等(1995)^[2]提出的离散选择需求模型和差异产品的伯川德竞争模型,并利用淘宝网上的交易数据,对声誉、消费者保障计划、保修服务及信息披露四种信号策略在网上交易中的作用进行了实证研究。需求估计结果表明消费者保障计划中的"7天无理由退换货"计划以及保修服务可以作为产品质量的信号;而在其他有效信号策略存在的情况下,消费者保障计划中的"先行赔付"计划以及卖家声誉作为质量信号的作用则被削弱。成本分析表明,信息披露虽然可以提高消费者购买的可能性,但是由于发出信号的成本太低,容易被低质量卖家所模仿,因此并不能作为有效的质量信号。本文首次从供给和需求两个方面分析了信号机制在信息不对称情况下的效应及其作用机制。     

Students’ health engagement and affective relations in Danish upper secondary school

To increase our understanding of the dynamics of young people’s embodied engagement in health, this article analyses Danish upper secondary school students’ understandings and practices of health and the role of the school environment in these dynamics. Participatory, visual and narrative data were collected during fieldwork with 37 students aged 16–17. Deleuze and Guattari’s philosophy of the body is applied to analyse the affective relations and emerging body-health assemblages within the students’ school life, which generated force and vitality (here conceptualised as health). Through becoming within sensuous, social and political body-health assemblages, the students attempted to curb school stress, sustain social belonging in an individualistic school environment and both reproduce affirming power discourses and subvert their territorialisation. The study proposes an analytical shift in perspective on young people’s health away from an individualistic ‘components approach’ towards a relational understanding, and suggests that students’ health at school relates to collectivity, quality, rhythm and co-produced engagement, rather than individuality, quantity, rules and performance, which increasingly characterise Danish health discourse and school policy.     

Observational sketching as method

This paper explores the potential of observational sketching as a social science research tool, informed by our own recent experiments with observational sketching techniques and approaches. We first outline the historical roots of academic sketching and note a recent resurgence of interest in sketching in certain disciplines. We then introduce our own explorations in sketching as method, based on a year-long collaboration between an observational artist and a group of qualitative researchers with interests in creative methods. The paper outlines some of the lessons we learnt from our partnership, focusing on three themes: (i) ‘sketchiness’; (ii) ‘concentrated seeing’ and (iii) sketching as interaction. We conclude that observational sketching generates a refreshingly different form of visual data which has considerable potential to be used as a complement to other methods, including as a participatory method and as a useful tool for thinking.     

Trend estimation of multivariate time series with controlled smoothness

This paper extends the univariate time series smoothing approach provided by penalized least squares to a multivariate setting, thus allowing for joint estimation of several time series trends. The theoretical results are valid for the general multivariate case, but particular emphasis is placed on the bivariate situation from an applied point of view. The proposal is based on a vector signal-plus-noise representation of the observed data that requires the first two sample moments and specifying only one smoothing constant. A measure of the amount of smoothness of an estimated trend is introduced so that an analyst can set in advance a desired percentage of smoothness to be achieved by the trend estimate. The required smoothing constant is determined by the chosen percentage of smoothness. Closed form expressions for the smoothed estimated vector and its variance-covariance matrix are derived from a straightforward application of generalized least squares, thus providing best linear unbiased estimates for the trends. A detailed algorithm applicable for estimating bivariate time series trends is also presented and justified. The theoretical results are supported by a simulation study and two real applications. One corresponds to Mexican and US macroeconomic data within the context of business cycle analysis, and the other one to environmental data pertaining to a monitored site in Scotland.     

The Peasant World in the Discourse of Generational Sorrow

This article spells out the methodological considerations and various procedural and methodological subtleties developed over the author's quarter century of sociological field studies of Russia's peasant worlds. Particular attention is paid to “voices from below”—peasant discursive formats that capture, in natural and undiluted form, the evolution of peasant practices constituting the core of everyday life. In particular, the phenomenon of generational sorrow and a special chronological nostalgia that functions as a “social gyroscope” is identified and discursively captured. This phenomenon is noteworthy and useful for its ability to retain a record of the productively longed for past in a rural community's collective memory and thereby influence new peasant worlds taking shape today.