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排序方式: 共有199条查询结果,搜索用时 15 毫秒
21.
Matthew B. Rhudy Scott B. Dreisbach Matthew D. Moran Marissa J. Ruggiero Praveen Veerabhadrappa 《Journal of sports sciences》2020,38(5):503-510
ABSTRACTAccelerometer cut points are an important consideration for distinguishing the intensity of activity into categories such as moderate and vigorous. It is well-established in the literature that these cut points depend on a variety of factors, including age group, device, and wear location. The Actigraph GT9X is a newer model accelerometer that is used for physical activity research, but existing cut points for this device are limited since it is a newer device. Furthermore, there is not existing data on cut points for the GT9X at the ankle or foot locations, which offers some potential benefit for activities that do not involve arm and/or core motion. A total of N = 44 adults completed a four-stage treadmill protocol while wearing Actigraph GT9X sensors at four different locations: foot, ankle, wrist, and hip. Metabolic Equivalent of Task (MET) levels assessed by indirect calorimetry along with Receiver Operating Characteristic (ROC) curves were used to establish cut points for moderate and vigorous intensity for each wear location of the GT9X. Area under the ROC curves indicated high discrimination accuracy for each case. 相似文献
22.
刘颖 《天津工程师范学院学报》2007,17(3):26-28,32
针对声纳水听器阵列比较突出的相位误差,研究了一种基于遗传算法的阵列校正方法。该方法利用无相位误差时阵列协方差矩阵具有Toeplitz结构的特性构造代价函数,并以此作为遗传算法中进化个体的适应度函数,由算法搜索的最优个体得到阵元相位误差的估值。计算机仿真结果表明,该方法可以明显地减小阵列相位误差对MUSIC算法DOA估计结果的影响。 相似文献
23.
Brendan O’Connell Paul De Lange Mark Freeman Phil Hancock Anne Abraham Bryan Howieson 《Assessment & Evaluation in Higher Education》2016,41(3):331-349
Reliable, consistent assessment process that produces comparable assessment grades between assessors and institutions is a core activity and an ongoing challenge with which universities have failed to come to terms. In this paper, we report results from an experiment that tests the impact of an intervention designed to reduce grader variability and develop a shared understanding of national threshold learning standards by a cohort of reviewers. The intervention involved consensus moderation of samples of accounting students’ work, with a focus on three research questions. First, what is the quantifiable difference in grader variability on the assessment of learning outcomes in ‘application skills’ and ‘judgement’? Second, does participation in the workshops lead to reduced disparity in the assessment of the students’ learning outcomes in ‘application skills’ and ‘judgement’? Third, does participation in the workshops lead to greater confidence by reviewers in their ability to assess students’ skills in application skills and judgement? Our findings suggest consensus moderation does reduce variability across graders and also builds grader confidence. 相似文献
24.
杨梅 《北京工业职业技术学院学报》2008,7(3):73-77
发动机电控管理系统经过细致的整车匹配标定,能够使汽车在行驶性、燃油经济性和排放性能等诸方面均有明显改善。“高寒试验”是汽车发动机电控系统标定中的一项重要环节,可以确保汽车满足低温环境下的启动和驾驶等方面的性能要求。 相似文献
25.
提出了一种利用高阶神经网络拟合VF型ADC输出特性的新方法,实现了VFC110芯片在4MHz满量程时的非线性估计.设计了两种动态在线标定电路用于提高采样精度.该方法也可用于类似场合的传感器输出特性的非线性拟合. 相似文献
26.
An equivalent relationship between electro-magnetic flowmeters (EMFs) and the Hall effect is discussed in principle and three
equivalent conclusions about their measuring equations are derived. Thereby, the calibration using the ionic current (CUIC)
is introduced to the calibration of EMFs in a special Hall effect system. A basic system with these equations is specially
given and discussed for realizing the method. Two key points about CUIC are proved by a simple experiment. 相似文献
27.
关于翻斗式雨量传感器误差检定的思考 总被引:1,自引:0,他引:1
分析了目前对安装在野外使用的翻斗式雨量传感器检定方法的不便,提出了适用野外模拟大、中、小雨强检定的新方法. 相似文献
28.
王华梅 《黄冈师范学院学报》2010,30(3):23-27
本文采用平面靶标的标定方法研究了平面圆靶标的相机标定。在标定过程中,考虑了透镜的径向畸变,首先对摄像机的内外参数用直接线性变换估算,然后应用Levenberg-Marquardt(L-M)非线性算法对所有参数进行优化。结果显示,相对误差的线性估算结果与L-M算法优化结果相比差别不大。因此,在实际标定中只需选择线性估算即可,其算法简单且能满足精度要求。 相似文献
29.
基于InSAR目标三维重建原理对分布式卫星SAR干涉测高系统模型及工作原理进行了分析,给出了完整的目标位置三维重建闭合形式解;并对影响三维重建精度的主要误差源——基线矢量误差和干涉相位误差进行了详细分析;最后通过仿真分析了基线矢量误差和干涉相位误差特性,从而为系统参量定标及其校正提供了基础. 相似文献
30.
提出一种基于游程统计和Walsh谱能量分布的调色板图像隐写分析方法,利用调色板颜色的奇偶值(parity value,P值)构造P值图像,通过游程统计和Walsh变换提取出46维特征,并用校准技术削弱载体图像差异对分析统计量的干扰.实验表明,该方法适用于EzStego、分量和以及最佳奇偶隐写等调色板图像隐写算法,比奇异颜色分析准确. 相似文献