共查询到20条相似文献，搜索用时 250 毫秒
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矩阵表示法贯穿干高等代数的各个章节,通过矩阵表示,许多高等代数中的问题都可归结为矩阵问题,而矩阵标准型的方法又是解决矩阵问题的重要方法之一,它的核心思想就是删繁就筒,充分体现了解决数学问题的"转换"思想.同时,矩阵的相似标准型经常应用于对实际问题的解决,求解递归数列的通项公式就是这样一类问题. 相似文献
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非负矩阵分解方法将人脸图像表示为基图像的线性组合,较好地提取了人脸的局部特征。应用非负矩阵分解和奇异值分解相结合的方法识别人脸,实验结果表明,这种方法并不能有效提高识别率。位面切割可有效降低人脸图像中的噪声信息,基于这一认识,笔者提取了将位面切割应用于人脸识别的方法,在ORL人脸库上的实验证明了这一方法的有效性。 相似文献
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针对传统趋势分析方法的不足之处,以及序列段内部趋势信息缺失的问题,本文提出一种改进的基于趋势距离的时间序列符号聚合近似表示方法。具体主要基于序列段起点值与终点值,利用趋势距离对不同趋势的差异性进行量化分析。通过趋势和均值信息对低维序列共同描述,与此同时,又提出了新的距离度量法,从理论角度充分证明,时间序列距离度量方法基于趋势距离时,不但可满足下界需求,并且与原方法相比,其下界紧凑性更好。比较分析结果证明,与原符号近似表示法相比,本文提出的基于趋势距离的时间序列符号近似表示法更有优势。 相似文献
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提出用字符串统一表示有符号的超长整数、实数的表示法,把任意超长数的四则运算过程转化为字符串处理过程。解决了超长数除法中的精度控制问题。提出分解定位法求无符号超长整数乘法。 相似文献
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全日制义务教育《数学课程标准》(实验稿)指出:“数学是人们对客观世界定性把握和定量刻画逐步抽象概括,形成方法和理论并进行广泛应用的过程。”由此可见,学习数学不只是掌握数学这门科学,还有比掌握科学更重要的东西,这种更重要的东西就蕴含在过程中或者也包括过程本身。传统 相似文献
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非负约束条件下组合证券投资决策的二次规划计算方法 总被引：2，自引：1，他引：1
本文讨论协方差矩阵是正半定（但它可以是非正定）且有非负约束条件下的实现预期投资收益率的组合证券投资问题,提出一种二次规划算法,并将该算法应用于一个三元证券投资问题 相似文献
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《黑龙江科技信息》2017,(34)
设向量则Y=(y_1,y_2,…y_n)~T∈R~n,则(|y_1|~D+|y_2|~D+…+|y_n|~D)~(1/D)=||Y||是Y的P-范数。如果||Y||=1,则Y是P-标准的。设非负不可约矩阵M,根据Perron-Frobenius定理,对任意给定的1≤p∞,矩阵M的谱半径都有唯一正的P-标准的特征向量Y与之对应,Y被称为相应矩阵的主特征向量。在这篇文章中确定了无符号拉普拉斯矩阵主特征向量最大分量的下界和最小分量的上界。拉普拉斯矩阵L(G)是半正定的,它的最大特征值不一定是单根。假定X=(X_1,X_2,…,x_n)~T是L(G)的谱半径所对应的P-标准的特征向量。在这篇文章中还确定了向量X~*=(|X_1|,|X_2|,…,|x_n|)~T中最大分量的下界。 相似文献
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爱因斯坦的科学经历铸就了他的数学信仰以及相应的方法论,广义相对论的成功使这种数学信仰得到强化,并使他在引入半矢量研究狄拉克方程过程中误入歧途。爱因斯坦的数学信仰过分夸大了纯数学方法揭示自然本体的作用。 相似文献
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《Journal of The Franklin Institute》2021,358(17):9288-9306
In this paper, the observer-based state estimation of discrete-time Takagi-Sugeno fuzzy systems is enhanced markedly by developing a distinctive multi-instant gain-scheduling law. Firstly, the updated information of both the past-time and the current-time normalized fuzzy weighting functions is fused into the proposed multi-instant gain-scheduling law in a comprehensive way, and it is important to point out that those existing ones reported in the literature belong to special cases of ours. Secondly, a set of time-varying free matrices for constructing more relaxed fuzzy observers are introduced for the first time in accordance with different operating modes. Moreover, the time-varying free matrices are more general than those previous time-invariant ones and most of them no longer need to be positive or negative definite. Therefore, a significant reduction in conservatism can be achieved at the expense of a slight increase in offline computing burden over those competing approaches. Finally, a set of numerical simulations are implemented to verify the superiority of the designed approach. 相似文献
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The general problem of root-clustering and root-distribution of a polynomial in a certain region Γ in the complex plane has been investigated in this paper. The region Γ is general and includes all the previously investigated regions. For the root-clustering problem, it is shown that by using a certain transformation, the necessary and sufficient condition can be represented either in terms of positive definite (p.d.) or positive innerwise (p.i.) matrices. The entries in these matrices are rational functions of the coefficients of the polynomial. The connection between p.d. and p.i. matrices is established in terms of matrix multiplication. 相似文献
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The paper proposes a method for structured state-feedback controllers design for linear time-invariant systems. A necessary and sufficient condition for structured state-feedback stabilizability of linear systems, making an appeal to the linear-quadratic (LQ) regulator theory, is first proposed. The latter is presented in the form of a nonlinear matrix equation. Then, it is recast as a nonsmooth unconstrained equation using projection onto the positive semi-definite matrices cone. Thereby, a nonsmooth Newton’s iterative algorithm, based on the Clarke generalized Jacobian of said projection, is proposed. This method has a guaranteed local convergence. Finally, numerical examples illustrate the effectiveness of the proposed method. 相似文献
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Examining the Influence of Emotional Expressions in Online Consumer Reviews on Perceived Helpfulness
《Information processing & management》2020,57(6):102266
Drawing on the cognitive appraisal theory of emotions and the attribution theory, this study extends existing research by examining how the emotional expressions influence perceived helpfulness of online consumer reviews (OCRs). We include two negative emotions (anger, fear) and two positive emotions (pride, surprise). Each of these four emotions can be described with respect to six emotional appraisal dimensions which containing certainty, pleasantness, attentional activity, anticipated effort, control and others’ responsibility. Hypotheses thus developed were empirically validated using the laboratory experiment in the context of restaurant services. Research results indicated that emotion expressions in OCRs have an indirect effect on perceived helpfulness through attribution about the reviewer's cognitive effort. We find that reviews with negative emotions are perceived to be more reviewer's cognitive efforts than positive emotions. More specifically, OCRs with negative emotions tend to comprise more diagnostic features related the product or service, and are more informative. We further examined whether the gender of reader moderates the relationship between different emotional expressions and perceived reviewer's cognitive effort. The results find that reviews conveying positive emotions tended to have a greater impact on male readers’ perception of reviewer's cognitive effort than those of female readers. Reviews conveying negative emotions were found to have a greater impact on female readers’ perception of reviewer's cognitive effort than that of male readers. The study results add to existing knowledge of the influence of emotional expression on perceived helpfulness, which will advance our understanding of information processing in the psychological mechanisms influencing the attitude. Applying the results from this study, restaurant service providers can make different coping strategy for discrete emotions and platform administrators can assistant reviewer express their emotions more precisely. 相似文献
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[目的/意义]旨在分析“出版直播”的媒介影响,为其今后健康发展提供参考。[方法/过程]根据目前“出版直播”的活动实例,从读者、出版业、社会文化三个角度分析其正负影响。[结果/结论]“出版直播”作为一种新的媒介,赋予了读者新的意义,使得出版业“名利双收”,进一步营造了书香社会;但其也伴随着负面影响,使得读者产生路径依赖,带来知识产权问题,同时也产生娱乐至死的苗头。 相似文献
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限制卖空的情形下，本文提出了一种求解高维数组合投资问题的转轴方法。该方法的优点在于能够处理各投资项目之间的协方差矩阵为半正定的情形。 相似文献
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通过测算中国工业行业技术进步,实证检验环境规制对技术进步的"波特假说"以及全球价值链(GVC)嵌入对该假说的影响。研究结果表明:(1)中国工业行业技术进步明显,高技术工业的技术进步明显高于传统工业,其中传统技术类行业技术急需升级;(2)环境规制强度与技术进步之间存在显著"U"型关系,这是挤出效应与补偿效应共同作用的结果;(3)GVC嵌入会强化环境规制对技术进步的挤出效应,但这种强化作用存在行业异质性特征,在技术类、生产者驱动型以及重工行业更为显著,在非技术类行业则可能转变为弱化作用。 相似文献
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In this paper, we discuss the properties of the eigenvalues related to the symmetric positive definite matrices. Several new results are established to express the structures and bounds of the eigenvalues. Using these results, a family of iterative algorithms are presented for the matrix equation AX=F and the coupled Sylvester matrix equations. The analysis shows that the iterative solutions given by the least squares based iterative algorithms converge to their true values for any initial conditions. The effectiveness of the proposed iterative algorithm is illustrated by a numerical example. 相似文献
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《Information processing & management》2016,52(1):93-98
In this paper, we analyze the influence of Twitter users in sharing news articles that may affect the readers’ mood. We collected data of more than 2000 Twitter users who shared news articles from Corriere.it, a daily newspaper that provides mood metadata annotated by readers on a voluntary basis. We automatically annotated personality types and communication styles of Twitter users and analyzed the correlations between personality, communication style, Twitter metadata (such as followig and folllowers) and the type of mood associated to the articles they shared. We also run a feature selection task, to find the best predictors of positive and negative mood sharing, and a classification task. We automatically predicted positive and negative mood sharers with 61.7% F1-measure. 相似文献
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《Journal of The Franklin Institute》2023,360(3):1690-1705
This paper proposes an extended generalized integral inequality based on free matrices (EGIIFM) and applies it to the stability analysis of neural networks with time-varying delays. The EGIIFM estimates an upper bound for a quadratic form of a positive definite matrix with an augmented vector staked not only with the state and its derivative but also with the nonlinear activation function. By reflecting the correlated cross-information among the terms in the augmented vector as free matrices, the EGIIFM provides a tighter upper bound and encompasses various existing single integral inequalities as special cases. In addition, by establishing a new double integral Lyapunov–Krasovskii functional including the correlated cross-information, a less conservative stability criterion is obtained. Through three well-known numerical examples, the effectiveness of the EGIIFM is evaluated. 相似文献