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991.
陈伦铭 《电子科技大学学报(社会科学版)》1996,(5)
具有共轭复数重特征值的系统(A,B,C)经状态变换为模式系统(M,B~,C~)且公式地写出eMt。在此基础上,导出了系统的观控性判据,从而有效地避免了不必要地把系统化为对角型或Jordan标准型来决定观控性。且暗示出一种把系统(A,B,C),特别是无论特征值相同或相重与否,也无论同一个特征值组成多个Jordan块与否的对角型或Jordan标准型状态变换为模式系统(M,B~,C~的方法 相似文献
992.
A system of predictors for estimating a finite population variance is defined and shown to be asymptotically design-unbiased (ADU) and asymptotically design-consistent (ADC) under probability sampling. An asymptotic mean squared error (MSE) of a generalized regression-type predictor, generated from the system, is obtained. The suggested predictor attains the minimum expected variance of any design-unbiased estimator when the superpopulation model is correct. The generalized regression-type predictor and the predictor suggested by Mukhopadhyay (1990) are compared. 相似文献
993.
通过库诺特模型可以说明,“假象”的存在将改变均衡结果:如果信息获取是无成本的,那么“假象”将使信息占优一方的均衡利润增加,其对手的均衡利润可能减少,也可能增加;如果获取对手的信息是有代价的,根据我们给出的信息投资的边界条件,当获取信息的代价大于这一边界条件时,获取对手信息是有必要的,反之,应该放弃对信息的投资。 相似文献
994.
Modeling the demand reduction input-output (I-O) inoperability due to terrorism of interconnected infrastructures. 总被引:1,自引:0,他引:1
Interdependency analysis in the context of this article is a process of assessing and managing risks inherent in a system of interconnected entities (e.g., infrastructures or industry sectors). Invoking the principles of input-output (I-O) and decomposition analysis, the article offers a framework for describing how terrorism-induced perturbations can propagate due to interconnectedness. Data published by the Bureau of Economic Analysis Division of the U.S. Department of Commerce is utilized to present applications to serve as test beds for the proposed framework. Specifically, a case study estimating the economic impact of airline demand perturbations to national-level U.S. sectors is made possible using I-O matrices. A ranking of the affected sectors according to their vulnerability to perturbations originating from a primary sector (e.g., air transportation) can serve as important input to risk management. For example, limited resources can be prioritized for the "top-n" sectors that are perceived to suffer the greatest economic losses due to terrorism. In addition, regional decomposition via location quotients enables the analysis of local-level terrorism events. The Regional I-O Multiplier System II (RIMS II) Division of the U.S. Department of Commerce is the agency responsible for releasing the regional multipliers for various geographical resolutions (economic areas, states, and counties). A regional-level case study demonstrates a process of estimating the economic impact of transportation-related scenarios on industry sectors within Economic Area 010 (the New York metropolitan region and vicinities). 相似文献
995.
996.
在对金融系统中货币供应量的预测进行相关研究的基础上,介绍了符合金融系统预测规律的灰色系统动态预测法,并根据中国货币供应量的实际数据进行了实证的预测检验。结果显示,这种方法简单,不需要借助于其他任何时间序列数据,需要数据量少,预测精确度高,对于近期预测尤其准确,也可进行中长期预测;实证预测结果也符合我国金融系统中货币供应量预测的实际。 相似文献
997.
制约民间投资增长的问题及对策 总被引:2,自引:0,他引:2
周群 《西北农林科技大学学报(社会科学版)》2004,4(2):59-64
我国投资运行的实践证明,民间投资在推动经济发展,促进产业结构调整,吸纳劳动力,缓解就业压力等方面,对国民经济和社会发展的作用非同一般。然而,由于投融资体制和政策环境的不完善,近年来民间投资的增长出现了一系列的结构失衡,投资增长速度相对趋缓。通过增强政府投资的"带动效应",加速金融创新,推广先进合理的融资模式等举措可以有效拉动民间投资的增长。 相似文献
998.
Recurrent events are frequently observed in biomedical studies, and often more than one type of event is of interest. Follow-up time may be censored due to loss to follow-up or administrative censoring. We propose a class of semi-parametric marginal means/rates models, with a general relative risk form, for assessing the effect of covariates on the censored event processes of interest. We formulate estimating equations for the model parameters, and examine asymptotic properties of the parameter estimators. Finite sample properties of the regression coefficients are examined through simulations. The proposed methods are applied to a retrospective cohort study of risk factors for preschool asthma. 相似文献
999.
Regression models for survival data are often specified from the hazard function while classical regression analysis of quantitative outcomes focuses on the mean value (possibly after suitable transformations). Methods for regression analysis of mean survival time and the related quantity, the restricted mean survival time, are reviewed and compared to a method based on pseudo-observations. Both Monte Carlo simulations and two real data sets are studied. It is concluded that while existing methods may be superior for analysis of the mean, pseudo-observations seem well suited when the restricted mean is studied. 相似文献
1000.
The DEDICOM model is a model to analyze square tables describing asymmetric relationships among n entities. Its importance in the asymmetric multidimensional scaling literature is due to the fact that several authors showed a large class of models to be simply a constrained version of DEDICOM. A typical example is the Generalized GIPSCAL proposed by Kiers & Takane. In this paper we present a new algorithm capable to fit, in the least squares sense, any DEDICOM constrained model. 相似文献