用多摄像机系统实现机械灵巧手动作控制

1　Introduction　Usingfree handgesturesforremotecontrolofob jectsisaneffectivewayofinteraction .Handgesturesarenaturalformsofcommunicationandareeasytolearn .Asinglegesturecanbeusedtospecifybothacommandanditsparametersindicatingthepositionsandmovementsofthehandandfingers,whichpro videahigherpotentialofexpression .Usingafreehand ,astheinputdevice ,eliminatestheneedforem ployingintermediatetransducers[1] .　Thewaysforrecognizingahandgesturewereclas sifiedassensors basedoneandvision basedone .Int…     

车载电源控制器标定软件设计

为提高电动汽车用电源控制器开发效率,利用 VisualStudio 开发基于 CCP 协议的上位机标定软件,自定义 CCP 控制命令并利用 CCP driver 编写下位机通信代码,同时在 AltiumDesigner 中绘制 CAN 通信电路图,完成上下位机之间通信模块软硬件设计,最后利用 CANTest 进一步验证收发数据的精确度。该上位机标定软件可实时监控并显示 MOSFET 内部温度、输入电压和输出电压、输入电流等数据。经大量实验测试结果表明,上下位机之间通信稳定可靠、传输速率快,可节约调试成本。     

System for Measuring Elevator Guide Rail Quality and Its Calibration

A system for measuring the quality parameters of elevator guide rails is developed. The quality parameters the system can measure include straightness, flatness, squareness, width and height of the rail. The system consists of six parts:main guideway, auxiliary guideway, reference rail, saddle, control casing and measured rail. The guide rail to be measured is mounted on a bed. The straightness errors of surfaces are checked by five linear displacement sensors mounted on the saddle. The deviation of readings from the sensor, which is in contact with top guiding surface, gives the straightness error of the surface and height of the rail. The other four sensors are used to measure side guiding surfaces respectively and give other parameters including flatness on the surfaces, squareness, width and height of the rail. A novel calibration method is also developed to calibrate the straightness motion error of the system in horizontal and vertical directions. The deflection deformation of the measured rail is fitted by using a fourth-order polynomial. Experimental results show that the uncertainty of the system on the side surfaces after compensating the straightness motion error is less than 0. 01 mm, and the uncertainty of the system on the top surface after compensating the straightness motion error and the deflection deformation of the rail is less than 0.03 mm.     

X射线图像和CT图像的投影配准

提出了一种基于Chamfer3-4距离变换和模拟退火优化的方法，用于X射线图像和CT图像间的配准．首先，建立一个初始化的几何变换矩阵．为了便于计算，通过X射线设备的几何模型重新建出变换矩阵．然后，通过定义三维投影和二维物体图像之间的距离，并且通过优化算法来使之达到最小．该方法同样被用于医学介入手术中，处理从三维图像工作站中获取的主动漫游数据．     

Calibration Between Undergraduate Students' Prediction of and Actual Performance: The Role of Gender and Performance Attributions

This study investigated changes in male and female students' prediction and postdiction calibration accuracy and bias scores, and the predictive effects of explanatory styles on these variables beyond gender. Seventy undergraduate students rated their confidence in performance before and after a 40-item exam. There was an improvement in students' bias between prediction and postdiction judgments, although male students' decrease in bias was greater than female students. Female students' accuracy remained stable from prediction to postdiction, and male students exhibited greater accuracy then females. Additionally, the task centered and student centered testing styles positively predicted students' accuracy while the social centered style was a negative predictor, beyond the effect of gender. In addition, no attribution was a significant predictor of bias.     

Calibrating assessment literacy through benchmarking tasks

Abstract

In calibration tasks students assess exemplar texts using criteria against which their own work will be assessed. Typically, these tasks are used in the context of training for peer assessment. Little research has been conducted on the benefits of calibration tasks, such as benchmarking, as learning opportunities in their own right. This paper examines a dataset from a long-running benchmarking task (～500 students per semester, for four semesters). We investigate the relationship of benchmarking performance to other student outcomes, including ability to self-assess accurately. We show that students who complete the benchmarking perform better, that there is a relationship between benchmarking performance and self-assessment performance, and that students appreciate the support for learning that benchmarking tasks provide. We discuss implications for teaching and learning flagging the potential of calibration tasks as an under-explored tool.     

Application of 2-D Position Sensitive Detector in Spatial Straightness Measurement of Guide Rails

A laser collimating system based on 2-D position sensitive detector (PSD) is presented in this paper. The working principle of PSD is depicted in detail. A calibration device was developed to check the nonlinearity errors of PSD and a multilayer feedforward neural network based on error back-propagation algorithm was used to compensate errors. With the aid of computer-based data acquisition system, an automatic dynamic measuring process was realized. A series of experiments, including comparison tests with laser interferometer, were done to evaluate the performance of the measuring system. The experimental results show that the spatial straightness errors of guide rails can be measured with high accuracy. The maximum differences between the device and laser interferometer are 0. 027 mm in Y direction, and 0. 053 mm in X direction in the measuring distance of 6 m.     

用电容式加速度传感器进行角度测量的非线性标定技术

针对采用基于电容传感原理的加速度传感器来实现角度测量时出现的非线性问题,提出数据预处理与广义回归神经网络(Generalized Regression Neural Network, GRNN)相结合的非线性标定技术.结合实验,详细分析该技术的标定过程,并对该技术与单一使用GRNN进行标定的标定结果进行对比.实验结果表明,该技术标定速度快、精度高、鲁棒性强、实时性好,能有效拓展电容式加速度传感器用于角度测量的线性范围,有较高的工程实用价值.     

Same,Similar, or Something Completely Different? Calibrating Student Surveys and Classroom Observations of Teaching Quality Onto a Common Metric

Using item response theory, this study explores whether student survey and classroom observation items can be calibrated onto a common metric of teaching quality. The data comprises 269 lessons of 141 teachers that were scored on the International Comparative Analysis of Learning and Teaching (ICALT) observation instrument and the My Teacher student survey. Using Rasch model concurrent calibration, items from both instruments were calibrated onto a common one‐dimensional metric of teaching quality. Most items were found to fit the model. Challenges pertain mainly to items measuring teaching students learning strategies and differentiation. Explanations for these difficulties are discussed.     

Rater calibration when observational assessment occurs at large scale: Degree of calibration and characteristics of raters associated with calibration

Observational assessment is used to study program and teacher effectiveness across large numbers of classrooms, but training a workforce of raters that can assign reliable scores when observations are used in large-scale contexts can be challenging and expensive. Limited data are available to speak to the feasibility of training large numbers of raters to calibrate to an observation tool, or the characteristics of raters associated with calibration. This study reports on the success of rater calibration across 2093 raters trained by the Office of Head Start (OHS) in 2008–2009 on the Classroom Assessment Scoring System (CLASS), and for a subsample of 704 raters, characteristics that predict their calibration. Findings indicate that it is possible to train large numbers of raters to calibrate to an observation tool, and rater beliefs about teachers and children predicted the degree of calibration. Implications for large-scale observational assessments are discussed.