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81.
Risk matrices are commonly encountered devices for rating hazards in numerous areas of risk management. Part of their popularity is predicated on their apparent simplicity and transparency. Recent research, however, has identified serious mathematical defects and inconsistencies. This article further examines the reliability and utility of risk matrices for ranking hazards, specifically in the context of public leisure activities including travel. We find that (1) different risk assessors may assign vastly different ratings to the same hazard, (2) even following lengthy reflection and learning scatter remains high, and (3) the underlying drivers of disparate ratings relate to fundamentally different worldviews, beliefs, and a panoply of psychosocial factors that are seldom explicitly acknowledged. It appears that risk matrices when used in this context may be creating no more than an artificial and even untrustworthy picture of the relative importance of hazards, which may be of little or no benefit to those trying to manage risk effectively and rationally. 相似文献
82.
高泽民 《绍兴文理学院学报》2005,(3)
我们利用向量组的线性相关性以及分块矩阵的运算性质给出了下列命题的另一种有趣的证法:若n阶对合矩阵A满足条件秩(A In)=r,则A相似于对角矩阵diag{Ir,-In-r}.这种证法连同Schmidt标准正交化方法一起,还可以用来证明:当上述矩阵A是实对称(Hermite)矩阵时,A正交(酉)相似于对角矩阵diag{Ir,-n-r}. 相似文献
83.
对一种新的补沃尔什哈达码-M(CWH-M)二维码,在空频二维OCDMA系统中的应用进行了研究, 实现了该码字的编解码方案和系统设计.理论分析得到该二维码在理论上可以实现完全正交,彻底消除多用户干扰.仿真结果表明了基于CWH-M二维码OCDMA系统性能比采用一维编解码方案和采用简单开关控制的二维编解码方案有了显著提高。 相似文献
84.
高泽民 《绍兴文理学院学报》2005,25(9):27-29
我们利用向量组的线性相关性以及分块矩阵的运算性质给出了下列命题的另一种有趣的证法:若n阶对合矩阵A满足条件秩(A+In)=r,则A相似于对角矩阵diag{Ir,-In-r}.这种证法连同Schmidt标准正交化方法一起,还可以用来证明:当上述矩阵A是实对称(Hermite)矩阵时,A正交(酉)相似于对角矩阵diag{Ir,-n-r}. 相似文献
85.
Graciela Boente Frank Critchley Liliana Orellana 《Statistical Methods and Applications》2007,15(3):295-327
In this paper, under a proportional model, two families of robust estimates for the proportionality constants, the common
principal axes and their size are discussed. The first approach is obtained by plugging robust scatter matrices on the maximum
likelihood equations for normal data. A projection- pursuit and a modified projection-pursuit approach, adapted to the proportional
setting, are also considered. For all families of estimates, partial influence functions are obtained and asymptotic variances
are derived from them. The performance of the estimates is compared through a Monte Carlo study. 相似文献
86.
给出了一些四元数自共轭矩阵积与Hadamard积的不等式.由此表明在很多情况下四元数自共轭矩阵积与Hadamard积的性质是相似的. 相似文献
87.
黄廷祝 《电子科技大学学报(社会科学版)》1993,(4)
文献[1]研究了具有广泛实际背景的M矩阵的不等式。本文指出了文献[1]的主要结果,即其定理1和定理3为著名的Hadamard-Fischer不等式的特款。 相似文献
88.
Abdessamad Saidi 《Revue canadienne de statistique》2007,35(1):169-188
A consistent approach to the problem of testing non‐correlation between two univariate infinite‐order autoregressive models was proposed by Hong (1996). His test is based on a weighted sum of squares of residual cross‐correlations, with weights depending on a kernel function. In this paper, the author follows Hong's approach to test non‐correlation of two cointegrated (or partially non‐stationary) ARMA time series. The test of Pham, Roy & Cédras (2003) may be seen as a special case of his approach, as it corresponds to the choice of a truncated uniform kernel. The proposed procedure remains valid for testing non‐correlation between two stationary invertible multivariate ARMA time series. The author derives the asymptotic distribution of his test statistics under the null hypothesis and proves that his procedures are consistent. He also studies the level and power of his proposed tests in finite samples through simulation. Finally, he presents an illustration based on real data. 相似文献
89.
复杂体系药物分析正面临在中药现代化进程中寻找各种生命现象物质基础的任务。对现代分析仪器的需求是 研制面向任务的 基于新原理、新技术以及由新理念(仪器=D/A(A/D)+CPU+software)指导的具有我国自主知识产权的世界一流水平的新型分析仪器。 相似文献
90.
Although generalized exchange remains an emblematical model of alliance theory, characterizing matrimonial systems as pertaining to this model is tricky. The necessary condition of generalized exchange is the deliberate preference for asymmetric exchanges. Given a marriage dataset, can we determine whether the observed pattern is due to the realization of a social norm enjoining symmetric or asymmetric exchange or is the result of random processes? Here, relevant probabilities and indexes are established in the framework of graph theory, and are validated using a demographic individual-based model. The methods are applied to three datasets from the literature, allowing to assess with great confidence that the observed marriage configurations were not random. 相似文献