共查询到20条相似文献，搜索用时 15 毫秒
1.
Joshua N. Pritikin Michael D. Hunter Timo von Oertzen Timothy R. Brick Steven M. Boker 《Structural equation modeling》2017,24(5):684-698
Structural equation models are increasingly used for clustered or multilevel data in cases where mixed regression is too inflexible. However, when there are many levels of nesting, these models can become difficult to estimate. We introduce a novel evaluation strategy, Rampart, that applies an orthogonal rotation to the parts of a model that conform to commonly met requirements. This rotation dramatically simplifies fit evaluation in a way that becomes more potent as the size of the data set increases. We validate and evaluate the implementation using a 3-level latent regression simulation study. Then we analyze data from a statewide child behavioral health measure administered by the Oklahoma Department of Human Services. We demonstrate the efficiency of Rampart compared to other similar software using a latent factor model with a 5-level decomposition of latent variance. Rampart is implemented in OpenMx , a free and open source software package. 相似文献
2.
采用调整三分视场寻找暗场以测定旋光度的实验方法,研究了钠灯、汞灯和日光灯对不同浓度蔗糖溶液旋光效应实验测量的影响。通过对测量数据的平均值、标准差以及最小二乘法直线拟合的斜率和相关系数的分析表明,对于单色的钠灯光源,在旋光度的测量准确度、旋光度与溶液浓度的直线拟合上都优于其他两种光源;而汞灯和日光灯的实验结果较为接近,这应该是与汞灯和日光灯有较为相似的线状光谱有关。此外,使用钠灯光源对比旋度的测量结果与已有的经验值也较为符合。因此,从实验的角度充分证明了钠灯是旋光效应实验测量效果非常好的一种光源。 相似文献
3.
为了提高篮球投篮的准确性,提出基于粒子滤波的篮球旋转投射最优角度分析计算方法。构建篮球旋转投射的动力学和运动学模型,结合动态差分模型进行篮球旋转投射的基元轨迹方程建模,采用最大似然估计方法进行篮球旋转投射最优角度的优化计算,并采用自适应的轨迹修正方法进行篮球旋转投射过程中的力学控制,实现篮球旋转投射最优角度分析。仿真结果表明,采用该方法进行篮球旋转投射最优角度计算的准确度较高,运动力学控制能力较好,具有较好的角度修正和轨迹跟踪能力,在篮球旋转投射运动学建模中具有很好的应用价值。 相似文献
4.
U（2）代数模型是研究原子分子光谱的一种有效工具,在该模型中用一个U（2）代数描述了分子中键的振动且将分子振动与转动分开讨论．当考虑分子的弯曲振动后,利用U（2）代数中的产生和湮灭算符构造HCP分子中CP犍的哈密顿量,通过拟合实验数据表明U（2）代数模型比其他模型能更好地描述该分子的高激发光谱数据． 相似文献
5.
社会经济调查中的样本轮换问题研究 总被引：1，自引：0，他引：1
在分析社会经济调查中样本轮换的原因后，对样本轮换率的确定方法进行了探讨，并在吸收前人优秀成果的基础上，提出了确定样本轮换率的两种方法：通过估计相关系数或根据设计效果系数来确定样本轮换率。子样本轮换是最好的样本轮换方法，美国每月零售贸易额调查的混合两水平样本轮换模式和现期人中调查的4—8—4模式是月度经常性抽样调查中两种比较理想的样本轮换模式。 相似文献
6.
AR(p)与指数平滑组合预测算法 总被引：1，自引：0，他引：1
本文提出一种对铜铳品位进行预测的新方法，以采集的现场数据为基础，采用系统辩识动态地建立了AR(p)模型与三次指数平滑模型，AR（p)模型要求数据对象是平衡时间序列，而三次指数平滑型的数据对象具有随机性，考虑到铜锍品位的波动性，本文将二模型按最小二乘法原理，以组合预测误差平方和为目标函数，通过使误差平方和极小化来确定两种预测方法的优化，建立了一种新的组合模型，在三种模型中其预测误差最小。 相似文献
7.
现有大部分融合跟踪算法都使用分类器型跟踪算法,这种算法在目标尺度发生变化时会存在一定误差。虽然已有一些解决方案,但仍不能从根本上解决该问题,而且一般无法估算目标的旋转状态。为此,基于CMT 算法提出一种新的基于点的多传感器融合跟踪算法。在获取目标状态上综合了多传感器信息,并对目标中心使用卡尔曼滤波进行修正,能够跟踪目标并获得目标的尺度及旋转信息。实验结果表明,该算法在常见分辨率下跟踪非旋转目标,重叠率与现有算法相当,在分辨率较高的情况下,在实时性上具有优势。 相似文献
8.
采用最小二乘法将方管周边的点拟合成旋转角度与高度的函数,通过提取的数组数据得出分段的函数关系式．进一步利用此函数关系式由Matlab软件绘制出拟合曲线． 相似文献
9.
Without sufficient real training data, the data driven classification algorithms based on boosting method cannot solely be utilized to applications such as the mini unmanned helicopter landmark image detection. In this paper, we propose an approach which uses a boosting algorithm with the prior knowledge for the mini unmanned helicopter landmark image detection. The stage forward stagewise additive model of boosting is analyzed, and the approach how to combine it with the prior knowledge model is presented. The approach is then applied to landmark image detection, where the multi-features are boosted to solve a series of problems, such as rotation, noises affected, etc. Results of real flight experiments demonstrate that for small training examples the boosted learning system using prior knowledge is dramatically better than the one driven by data only. 相似文献
10.
基于黄金分割律的易拉罐形状和尺寸的最优设计 总被引：1，自引：1，他引：0
基于黄金分割律的设计理念,应用目标规划的方法建立了易拉罐形状和尺寸最优设计的简化模型与改进模型,以拉格朗日乘数法求解了简化模型,利用mathematic求出了改进模型数值解,并通过测量数据进行了验证. 相似文献
11.
WU Xue-dong SONG Zhi-huan 《浙江大学学报(A卷英文版)》2007,8(10):1604-1613
Determination of relative three-dimensional (3D) position, orientation, and relative motion between two reference frames is an important problem in robotic guidance, manipulation, and assembly as well as in other fields such as photogrammetry. A solution to pose and motion estimation problem that uses two-dimensional (2D) intensity images from a single camera is de- sirable for real-time applications. The difficulty in performing this measurement is that the process of projecting 3D object features to 2D images is a nonlinear transformation. In this paper, the 3D transformation is modeled as a nonlinear stochastic system with the state estimation providing six degrees-of-freedom motion and position values, using line features in image plane as measuring inputs and dual quaternion to represent both rotation and translation in a unified notation. A filtering method called the Gaussian particle filter (GPF) based on the particle filtering concept is presented for 3D pose and motion estimation of a moving target from monocular image sequences. The method has been implemented with simulated data, and simulation results are provided along with comparisons to the extended Kalman filter (EKF) and the unscented Kalman filter (UKF) to show the relative advantages of the GPF. Simulation results showed that GPF is a superior alternative to EKF and UKF. 相似文献
12.
13.
Biclustering is a method of grouping objects and attributes simultaneously in order to find multiple hidden patterns.When dealing with a long time series,there is a low possibility of finding meaningful clusters of whole time sequence.However,we may find more significant clusters containing partial time sequence by applying a biclustering method.This paper proposed a new biclustering algorithm for time series data following an autoregressive moving average （ARMA） model.We assumed the plaid model but modified the algorithm to incorporate the sequential nature of time series data.The maximum likelihood estimation （MLE） method was used to estimate coefficients of ARMA in each bicluster.We applied the proposed method to several synthetic data which were generated from different ARMA orders.Results from the experiments showed that the proposed method compares favorably with other biclustering methods for time series data. 相似文献
14.
采用文献资料法、数理统计法、问卷调查法和教学实验法,对目标教学模式在乒乓球普修技术教学中的应用进行研究．表明：在乒乓球普修课中实施目标教学模式教学,其教学效果优于常规教学．教学目标的层次性,使学生的学习积极性大大提高,发挥了学生的潜在能力,提高学生的学习水平．形成性评价及“反馈一矫正”策略,有利于学生对运动技术的学习与掌握,为教师的再教学提供有力保障． 相似文献
15.
16.
本文提出了一种能读取电感式电能表正反向计量数据的抄表器设计方案，采用该方案设计的抄表器不仅适用于普通居民家庭和企事业单位电能电度表的自动抄表，而且也适用于要求能计量反向供电的特殊用户。文中提出的方案已经取得了成功的应用，显示出其良好的推广前景。 相似文献
17.
A first-order torsion theory based on Vlasov theory has been developed to investigate the restrained torsion of open thin-walled
beams. The total rotation of the cross section is divided into a free warping rotation and a restrained shear rotation. In
first-order torsion theory, St. Venant torque is only related to the free warping rotation and the expression of St. Venant
torque is derived by using a semi-inverse method. The relationship between the warping torque and the restrained shear rotation
is established by using an energy method. The torsion shear coefficient is then obtained. On the basis of the torsion equilibrium,
the governing differential equation of the restrained torsion is derived and the corresponding initial method is given to
solve the equation. The relationship between total rotation and free warping rotation is obtained. A parameter λ, which is associated with the stiffness property of a cross section and the beam length, is introduced to determine the condition,
under which the St. Venant constant is negligible. Consequently a simplified theory is derived. Numerical examples are illustrated
to validate the current approach and the results of the current theory are compared with those of some other available methods.
The results of comparison show that the current theory provides more accurate results. In the example of a channel-shaped
cantilever beam, the applicability of the simplified theory is determined by the parameter study of λ. 相似文献
18.
研究了一种用于倾角传感器动态标定的系统。该系统包括工作台及其控制装置、传感器动态输出数据采集模块、数据处理模块等部分。该系统通过改变输入到驱动器的脉冲频率控制步进电机的转速,并通过调整脉冲数来控制旋转角度,从而获得一定转速下-45°～45°范围内倾角传感器的动态输出。利用Matlab软件对所得数据进行预处理、插值和拟合,建立了动态特性的数学模型,得出在不同转速下倾角传感器的动态补偿量,以用于动态测量过程的实时补偿。 相似文献
19.
为了保障风机的正常运行,提出基于自编码（Autoencoder,AE）的风机故障检测方法。依据法国风机ENGIE公开的风速传感器数据,建立欠完备自编码模型（UAE）、去噪自编码模型（DAE）与收缩编码器（CAE）模型,对风机风速传感器数据进行编码和解码,计算重构误差并设定阈值进行故障检测。用多风机风速传感器数据建立PCA模型并与去噪编码器模型对比。根据ROC曲线与AUC值对比,得出欠完备自编码模型、去噪自编码模型、收缩编码器模型均可用于风机异常检测,且收缩编码器效果最好的结论。PCA模型也可用于故障检测,同时多风机故障检测效果高于单一风机。 相似文献
20.
谢爱良 《临沂师范学院学报》2011,(6):78-85
基于旅游的定义提出了和谐旅游的概念体系。基于生态足迹模型,结合旅游者的生态消费及结构特征,将旅游生态足迹引入区域旅游和谐度评估中,阐述了旅游生态足迹模型及其计算方法,并分别对旅游餐饮、旅游住宿、旅游交通、旅游游览、旅游购物、旅游娱乐等子模型进行了测算。以文峰山景区为例,计算分析了2010年文峰山游客的旅游生态足迹．结果表明：2010年文峰山游客的人均旅游生态足迹为0．016354hm^2／人,当地的人均旅游生态承载力为0．032127hm2／人．生态盈余为0．015773hm2／人。由此可知研究区域旅游生态足迹处在旅游生态承载力范围之内．旅游生态占用率不高．旅游业处于和谐发展状态．说明景区的旅游业发展与生态保护相协调． 相似文献