基于BP网络的有教师分类算法及应用     

唐凤仙  汤鹏杰 《河池学院学报》2011,31(2):41-45

介绍BP神经网络的结构及相关算法,并通过实验比较不同情况下对BP神经网络的收敛速度与分类精度的影响。实验表明,合适的参数设置能提高BP神经网络算法的分类精度。  相似文献   

焊接机器人模块化工装组夹及复现工艺研究     

胡战明  宋博宇  张学海  李学强 《包头职业技术学院学报》2021,(1):1-2,31

焊接机器人工装组夹及产品复现在生产中是极为重要的,文章针对焊接机器人对工装精确度的要求,采用棋盘方格定位法和复现工艺,实现了焊接工装和机器人重复定位精度的要求,在多种产品上得到应用推广。  相似文献   

The Domain-Specificity of Elementary School Teachers’ Judgment Accuracy     

《Contemporary educational psychology》2023

Teachers’ diagnostic competence for accurately judging students’ achievement is essential for instructional practice and professional decisions. To promote their judgment accuracy, it is important to know if this is a general or domain-specific skill. We investigated teachers’ judgment accuracy in German language (one subdomain: reading) and mathematics (two subdomains: geometry; stochastics) and examined differences across domains (i.e., German and mathematics) and across subdomains (reading; geometry; stochastics). We examined the judgment accuracy of 59 German elementary school teachers who teach both German and mathematics, judging the achievement of 1227 students in the three subdomains. We conducted multilevel analyses with a subsample of 39 teachers and 787 students and calculated different accuracy components (i.e., rank, level, and differentiation) to examine the comparability of our results. In line with prior research, findings revealed that teachers’ judgments were fairly accurate. However, there were significant differences between teachers’ average judgment accuracy in different subdomains (between-person comparisons) and no or only a weak relation between individual teachers’ judgment accuracy in different subdomains (within-person comparisons). Findings support the notion that teachers’ judgment accuracy of student achievement is domain-specific with respect to the investigated subdomains. Practical implications for the promotion of teacher judgment accuracy are discussed.  相似文献   

黄河干流控制性梯级水库联合运行对下游水文情势的影响     

黎云云  畅建霞  涂欢  金文婷 《资源科学》2014,36(6):1183-1190

为评价黄河干流控制性梯级水库联合运行对下游水文情势的改变程度,根据花园口水文站1949-2010年的日径流资料,在水文改变指标体系(IHA)的基础上,采用变异范围法(RVA),定量分析了不同梯级水库联合运行前后,黄河下游水文情势变化情况及改变程度。分析结果表明:①梯级水库联合运行后,黄河下游的水文情势发生了高度改变,且改变度随着水库联合运行数量的增加而增强;②刘家峡和三门峡二库运行阶段,水文情势改变度为68.92%;刘家峡、龙羊峡和三门峡三库运行阶段,改变度为73.21%;龙羊峡、刘家峡、三门峡和小浪底四库运行阶段,改变度为87%;③不同水库联合运行对黄河下游生态水文特征的影响差异较大,尤其是四库联合调度后,汛期流量剧减,低流量频繁出现,致使河道的生物量和多样性急剧下降,严重危害河流生态健康。  相似文献   

车轴加工流水线提高定位精度和运行安全的措施     

任荣 《中国科技纵横》2014,(16):77-77

太原北车辆段2013年轮轴生产线改造的主体工程--车轴加工流水线建造投产,是全路第一条半龙门轨道机械手运行模式流水线,设计五台车轴机械手完成生产过程中车轴工件的自动输送作业。由于采用伺服系统的空中作业方式,最直接的优点是输送快速准确、传递效率高、工作环境简洁开阔,但另一方面由于是空中输送,机械手上下料定位准确性、运行安全意识丝毫不能松怠。  相似文献   

Achievement and engagement: How student characteristics influence teacher judgments     

《Learning and Instruction》2013

Teachers' judgments of student characteristics are affected not only by the characteristic in question, but also by other factors. This article presents three studies examining whether students' achievement influences teachers' judgments of their engagement (as a proxy for motivation) and vice versa. First, a field study was conducted with N = 52 teachers and N = 1135 students. Structural equation modeling revealed an effect of student achievement on teacher judgments of student engagement and an effect of student engagement on teacher judgments of student achievement—above and beyond the association of each student characteristic with teacher judgments of that characteristic. These results were then replicated in two experimental studies involving a computer simulation of an instructional situation, the Simulated Classroom, with N = 40 and N = 181 teacher candidates, respectively. The psychological determinants of the effects observed are discussed, as are their practical implications.  相似文献   

乒乓球运动员应加强快速、准确、灵活的步法训练   总被引：1，自引：0，他引：1  

孙文君 《体育科学研究》1997,(2)

论述了乒乓球运动员在短时间内,根据来球方向、速度、落点以及旋转等快速作出判断时步法移动的重要意义,并提出一些训练措施。  相似文献   

非球面塑料透镜两步注射成型法的探索     

吴呼玲 《陕西国防工业职业技术学院学报》2006,(3)

非球面透镜在各类光电系统中得到了越来越多的应用,但扩大塑料非球面透镜生产的最大障碍仍然是注射成型的精度问题。本课题在了解传统注射成型的基础上,从光学塑料的物理特性出发,详细的研究了它在成型过程中的精度问题。通过对典型材料P—V—T特性曲线的分析,发现了光学塑料在成型时的体积可控制,从而提出了两步注射成型法的新方法。  相似文献   

竞技性健美操技术的力度,幅度及准确性   总被引：2，自引：0，他引：2  

张海莉 《上海体育学院学报》1993,17(4):67-70

力度、幅度、准确性是评价竞技性健美操技术动作质量高低的重要依据。速度和力量的有机揉合,是力度的表现特征;手臂动作的幅度,直接影响整体动作的幅度;准确性是对力度、幅度、节奏及表现力的综合体现。  相似文献   

对第27届奥运会游泳成绩的灰色预测   总被引：1，自引：0，他引：1  

张芝兰  徐明  刘艇 《上海体育学院学报》1997,(3)

以单序列一阶线性动态模型为灰色模型,用微分动态建模法进行单序列残差辨认预测。结果显示,对第27届奥运会游泳成绩的预测值,与美国、前苏联、前西德等国的专家用不同方法预测的2000年游泳纪录非常接近,有的完全相等。其逐点精度检验效果较好。  相似文献