工业摄影测量技术在矿用机械臂末端位姿测量中的应用

矿用机械臂是多类矿山装备的核心功能模块，精准测量矿用机械臂末端位姿参数是开展其状态监测与智能控制的关键环节之一。利用具备大尺寸、非接触、高精度优势的摄影测量技术，解决了以破碎机为代表的矿用机械臂末端参数的高精度实时动态测量问题，为矿用机械臂的智能控制提供基础支撑。     

Human uncertainty in explicit user feedback and its impact on the comparative evaluations of accurate prediction and personalisation

ABSTRACT

In this article, we report on the lack of reliability of explicit user feedback and its interpretation in the light of system evaluation. It is known, that given feedback strongly depends on the situational context. But also when many contextual factors are held constant, user feedback still proves to be unreliable. This impacts the evaluation of predictive algorithms since it is not clear whether a deviation between a user response and its corresponding prediction can be seen as a flaw by the system or just as usual ‘human uncertainty’. As a result, the perspective on the evaluation of adaptive systems basically changes. The main goal of this article is to demonstrate that simply increasing the amount of explicit feedback is not the key to sustainable system design innovation, as long as that information is not appropriately evaluated. To this end, we will exploit a novel probabilistic approach of processing user feedback and identify biasing effects on accuracy metrics, error probabilities for system rankings as well as natural limitations of evaluation. Finally, we will discuss possible solution strategies and give advice for handling explicit user feedback that is associated with uncertainty.     

异螺距万分尺设计

介绍了一种螺旋万分尺的结构设计。该万分尺的微分筒采用双螺纹,两螺纹的螺旋方向相同,螺距不同。采用V型槽和V型块精确定位来增加量程。测量最小刻度可达0.001 mm,读数精度达0.0001 mm。万分尺采用纯机械结构,结构原理简单,制造安装方便。     

气体静压轴承与主动磁轴承混合支撑轴系结构设计及静态性能研究

针对由气体静压轴承作为支撑的气浮精密主轴存在承载力相对较小及可控性不高的问题,结合带有周向微通槽的气体静压轴承与基于增量式PID控制的主动磁轴承,设计一款气磁混合支撑主轴。为提高小孔节流气体静压轴承的承载力,将气体静压轴承内表面的稳压室用矩形、三角形、半圆形截面动压微通槽相连通,通过FLUENT仿真分析3种截面动压微通槽对轴承承载能力的影响;以主轴的回转精度为衡量标准,在Matlab Simulink中仿真分析增量式PID控制的主动磁轴承的性能。结果表明:3种截面动压微通槽能有效提高气体静压轴承的承载能力,其中同等条件下矩形截面效果最好,可使轴承的承载力提高54%;基于增量式PID控制的主动磁轴承能够有效提高主轴的稳态响应速度及回转精度,使其在启动40 s后保持0.2μm的回转精度。     

RV减速器摆线针轮齿廓修形回差影响分析

针对RV减速器回差精度问题,建立了摆线针轮齿廓修形的回差精度数值分析模型,采用几何法求解各种常见修形方式产生的几何回差,同时考虑摆线针轮传动中的弹性回差,推导出摆线轮齿廓修形的回差影响公式,并讨论了同一摆线轮齿廓修形方式下不同的修形参数与同一修形参数下不同的修形方式对回差的影响,得出在同一修形量的条件下,等距加移距的组合修形方式的回差影响最小,移距修形的回差影响最大。对RV-40E型减速器样机进行试验验证,与传统回差公式相比较,文章推导的回差公式精度提高6%左右。     

黄土高原典型流域网格化逐时降水融合产品CMPA V1.0的精度分析

选取黄土高原无定河、窟野河和皇甫川流域为研究区,从水文应用角度评估了中国自动站与CMORPH融合的逐时降水产品(CMPA V1.0)的精度。结果表明,CMPA V1.0降雨数据总体上较雨量站实测值偏低;与6、9月相比,8月降水产品精度较低。随降水量级的增加,CMPA V1.0对降水事件发生频次的监测能力和对降水事件监测的稳定性有所降低,误报率整体升高;CMPA V1.0低估了小雨的发生频率及降水贡献率,高估了雨强大于2.5mm/h降雨的发生频率及降水贡献率;CMPA V1.0能合理地反映研究区降水的日变化过程,但低估了研究区的时段平均降水量和时段平均降水频率,高估了研究区14:00前的时段平均降水强度。     

车载移动测量系统定位准确度测试方法研究

阐述了移动测量系统的定位准确度需求,对圆概率法、均方差法和中误差法三种位置准确度评估方法进行分析比较,并在标准试验场内开展了车载GNSS/INS定位准确度测试。实验证明:中误差法的评估结果最准确,其误差小于1 m,明显优于圆概率法和均方差法。     

一种开合式微型电流互感器的设计与实验分析

针对不方便断电拆线的场合，设计了一种开合式微型电流互感器来代替常规电流互感器，从而实现在线安装.通过选择方形铁芯，选用磁导率较大且切口平整、气隙较小的铁氧体为铁芯材料，设计了互感器的外壳结构.经过实验分析表明，这种开合式微型电流互感器具有结构简单、使用方便、精度相对较高、线性度好的优点，并针对其正常工作时温升的情况及其漏磁对周围电子器件的影响做了数据分析.最后指出了提高其精度的改进措施.     

Don't Judge a (Face)Book by its Cover: Exploring judgement accuracy of others' personality on Facebook

With interaction across social networking sites (SNSs) becoming more prominent, the ability to accurately judge another's personality through these digital platforms is an important area of investigation. A number of studies demonstrate that SNSs can be an effective means of communicating information on personality (Evans, Gosling & Carroll, 2008). Much less research has examined the online cues that people use when forming their impressions of another's personality. The current research adopted a mixed methods approach to examine 1) accuracy of first impressions formed on the basis of viewing a person's Facebook behaviour and 2) how judgements are formed. Findings suggested that the traits of openness and conscientiousness can be judged most accurately through observing Facebook behaviour. To explore the cues used in forming personality judgements, thematic analysis was undertaken. This revealed six information ‘cues’ including; (1) vocabulary of target, (2) photographs, (3) written online interactions, (4) relationships with others, (5) health status and, (6) occupational status. Findings are discussed in terms of Funder's Realistic Accuracy Model (1995, 1999) along with limitations and suggestions for future research.     

Boosting metacomprehension accuracy in computer-supported learning: The role of judgment task and judgment scope

Although learners' judgments of their own learning are crucial for self-regulated study, judgment accuracy tends to be low. To increase accuracy, we had participants make combined judgments. In Experiment 1, 247 participants studied a ten-chapter expository text. In the simple judgments group, participants after each chapter rated the likelihood of answering correctly a knowledge question on that chapter (judgment of learning; JOL). In the combined judgments group, participants rated text difficulty before making a JOL. No accuracy differences emerged between groups, but a comparison of early-chapter and late-chapter judgment magnitudes showed that the judgment manipulation had induced cognitive processing differences. In Experiment 2, we therefore manipulated judgment scope. Rather than predicting answers correct for an entire chapter, another 256 participants rated after each chapter the likelihood of answering correctly a question on a specific concept from that chapter. Both judgment accuracy and knowledge test scores were higher in the combined judgments group. Moreover, while judgment accuracy dropped to an insignificant level between early and late chapters in the simple judgments group, accuracy remained constant with combined judgments. We discuss implications for research into metacomprehension processes in computer-supported learning and for adaptive learner support based on judgment prompts.