共查询到20条相似文献，搜索用时 250 毫秒
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The present study, employing a 2×2 design, examines the independent and interactive effects of two experimentally manipulated variables, Anonymity (A) and Retaliatory Potential (RP), on students' ratings of faculty performance. Data were obtained from 188 students at a large midwestern university using an instrument that had been specially developed for the study. A hypothesized main effect was found for A: The professor was rated more positively by students completing signed ratings than those completing ratings anonymously. The data showed no support, however, for the hypothesized RP main effect or the A×RP interactive effect. Practical implications of the study's findings are discussed. 相似文献
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This article proposes 2 classes of ridge generalized least squares (GLS) procedures for structural equation modeling (SEM) with unknown population distributions. The weight matrix for the first class of ridge GLS is obtained by combining the sample fourth-order moment matrix with the identity matrix. The weight matrix for the second class is obtained by combining the sample fourth-order moment matrix with its diagonal matrix. Empirical results indicate that, with data from an unknown population distribution, parameter estimates by ridge GLS can be much more accurate than those by either GLS or normal-distribution-based maximum likelihood; and standard errors of the parameter estimates also become more accurate in predicting the empirical ones. Rescaled and adjusted statistics are proposed for overall model evaluation, and they also perform much better than the default statistic following from the GLS method. The use of the ridge GLS procedures is illustrated with a real data set. 相似文献
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给出计算拟斜循环矩阵与向量乘积的算法,该算法需要3/2n^2＋O（n）个浮点数运算,而相比之下,常规的矩阵与向量的乘积运算则需要2n^2＋O（n）个浮点数运算,对于Hermitian循环矩阵,能得到类似的结果。 相似文献
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Ill conditioning of covariance and weight matrices used in structural equation modeling (SEM) is a possible source of inadequate performance of SEM statistics in nonasymptotic samples. A maximum a posteriori (MAP) covariance matrix is proposed for weight matrix regularization in normal theory generalized least squares (GLS) estimation. Maximum likelihood (ML), GLS, and regularized GLS test statistics (RGLS and rGLS) are studied by simulation in a 15-variable, 3-factor model with 15 levels of sample size varying from 60 to 100,000. A key result showed that in terms of nominal rejection rates, RGLS outperformed ML at all sample sizes below 500, and GLS at most sample sizes below 500. In larger samples, their performance was equivalent. The second regularization methodology (rGLS) performed well asymptotically, but poorly in small samples. Regularization in SEM deserves further study. 相似文献
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基于被删减二元关系的可达性矩阵求解 总被引：1，自引：0，他引：1
利用邻接矩阵求解有向图的可达性矩阵,计算量大,提出将有向图表达成二元关系,忽略环和回路的处理,通过计算被删减二元关系的传递闭包来求解可达性矩阵,利用新方法可以较快地实现可达性矩阵的求解。 相似文献
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肖业胜 《武汉工程职业技术学院学报》2014,(1):43-47
通过对一个力学问题的分析,构建了它的数学模型f=ATCAx,其系数矩阵T=ATCA是一个包含数字-1,2,-1的三对角矩阵。仅对矩阵T施行初等变换所得到的LU,LDLT分解等,具有非常简单的表示形式,它们在数值上呈现出很好的规律性;进一步的分析表明,这个力学系统是稳定的正定系统。 相似文献
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彭卓华 《赣南师范学院学报》2008,29(3):15-17
提出一种迭代法求最小二乘问题min‖AXB-C‖的对称解.通过这种方法,给定初始对称矩阵X1,在没有舍入误差的情况下,经过有限步迭代,找到它的一个对称解.并且,通过选择一种特殊的初始对称矩阵,得到它的最小范数对称解X^＊.另外,给定矩阵X0,通过求解最小二乘问题min‖AXB-C‖（其中C=C-AX0B）,得到它的最佳逼近对称解. 相似文献
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A multidimensional scaling (MDS) model is proposed for 2-way 1-mode asymmetric dissimilarity data, to estimate the unknown symmetric subjacent dissimilarity matrix while the objects are represented in a low-dimensional space. In the context of least squares MDS allowing transformations, and considering both triangular parts of the asymmetric dissimilarity matrix as effects of the unobserved symmetric dissimilarities, an alternating estimation procedure is proposed in which the unknown symmetric dissimilarity matrix is estimated in a covariance structure framework. Real and artificial data are analyzed to illustrate the proposed procedure. 相似文献
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在矩阵特征值分布理论和APA算法的基础上,给出了一种求非对称实矩阵特征值问题的并行NSM-APA算法,理论分析和在PVM下的数值结果表明,该算法比基于矩阵特征值分布理论的二分法收敛快,而且有较高的加速比. 相似文献
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校正变换矩阵法用于多组分染色剂的同时测定研究 总被引：1，自引：1，他引：0
将校正变换矩阵法(CTM)与可见分光光度法相结合,对藏红、荧光桃红、曙红三种染色剂进行不经分离同时测定.使用交叉验证法选择主因子数建立了校正模型,预测结果令人满意.在相同条件下,将校正变换矩阵法与偏最小二乘(PLS)回归的结果进行了比较,结果表明两种方法的预测准确性没有显著性差异. 相似文献
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一种新的PET序列图像超分辨率优质重建算法 总被引：1，自引：1，他引：0
利用超分辨率重建技术,从含有加性高斯噪声和模糊噪声的正电子发射成像(PET)序列低分辨率图像,重建出一幅优质高分辨率图像。作者提出了一种基于正则化参数(RP)的通道自适应线性斜率超分辨率算法。该算法采用平移运动模型,通过对RP线性斜率的自适应更新,动态优化代价函数,以降低对PET图像高频成分的抑制。为验证新算法的有效性,采用模拟PET序列图像进行实验。实验中,与HUHE算法相比,新算法PSNR平均提高2.65dB。新算法在改善图像空间分辨率上取得良好的效果,同时具有很好的抗噪性能。 相似文献
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三角矩阵求逆的一种方法 总被引：5，自引：0，他引：5
杨明顺 《渭南师范学院学报》2003,18(5):12-13
文章讨论了怎样较快的求出三角矩阵的逆阵，并给出了一种快速计算三角矩阵的逆矩阵的方法。 相似文献
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SU Cheng-li WANG Shu-qing 《浙江大学学报(A卷英文版)》2006,7(10):1723-1732
INTRODUCTION In recent years, research on nonlinear model predictive control has attracted significant attention because most practical processes are nonlinear. In industry process control, model predictive controllers based on linear models (LMPC) are often used to control nonlinear systems. When the operating con- ditions undergo significant changes, the performance of LMPC can deteriorate drastically. Under such conditions, predictive control based on nonlinear models (NMPC) shoul… 相似文献
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BAI Lei-shi HE Li-ming TIAN Zuo-hua SHI Song-jiao 《浙江大学学报(A卷英文版)》2006,7(10):1733-1741
INTRODUCTION Due to increasing demand for higher perform- ance, as well as for higher safety and reliability standards, the model-based approaches to fault de- tection and isolation (FDI) for dynamic systems have received more and more attention during the last two decades (Chen and Patton, 1999; Chen and Saif, 2006 Frank and Ding, 1997; Gao and Wang, 2006; Jiang and Zhou, 2005; Zhou et al., 1998). Among these model-based approaches, the most common way is the observer-based approach… 相似文献
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This paper presents a new genetic algorithm for the resource-constrained project scheduling problem(RCPSP).The algorithm employs a standardized random key(SRK) vector representation with an additional gene that determines whether the serial or parallel schedule generation scheme(SGS) is to be used as the decoding procedure.The iterative forward-backward improvement as the local search procedure is applied upon all generated solutions to schedule the project three times and obtain an SRK vector,which is rese... 相似文献
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We derive necessary and sufficient conditions for the existence and an expression of the （anti）reflexive solution with respect to the nontrivial generalized reflection matrix P to the system of complex matrix equations AX = B and XC = D. The explicit solutions of the approximation problem min x∈Ф ｜｜X - E｜｜F was given, where E is a given complex matrix and Ф is the set of all reflexive （or antireflexive） solutions of the system mentioned above, and ｜｜·｜｜ is the Frobenius norm. Furthermore, it was pointed that some results in a recent paper are special cases of this paper. 相似文献