基于QFD矩阵的竞争战略决策框架

借助于全面质量管理理论中的QFD矩阵,本文提出了一种顾客导向的竞争战略决策框架,它有效地将内部竞争能力与外部竞争要素放在一起进行分析与决策。文中还进一步探讨了其中的竞争要素的特征以及竞争冲击曲线理论,为有效地作出竞争战略决策提供了基础。     

Maximum entropy estimation for survey sampling

Calibration methods have been widely studied in survey sampling over the last decades. Viewing calibration as an inverse problem, we extend the calibration technique by using a maximum entropy method. Finding the optimal weights is achieved by considering random weights and looking for a discrete distribution which maximizes an entropy under the calibration constraint. This method points a new frame for the computation of such estimates and the investigation of its statistical properties.     

On some mixture models based on the Birnbaum-Saunders distribution and associated inference

In this paper, we consider three different mixture models based on the Birnbaum-Saunders (BS) distribution, viz., (1) mixture of two different BS distributions, (2) mixture of a BS distribution and a length-biased version of another BS distribution, and (3) mixture of a BS distribution and its length-biased version. For all these models, we study their characteristics including the shape of their density and hazard rate functions. For the maximum likelihood estimation of the model parameters, we use the EM algorithm. For the purpose of illustration, we analyze two data sets related to enzyme and depressive condition problems. In the case of the enzyme data, it is shown that Model 1 provides the best fit, while for the depressive condition data, it is shown all three models fit well with Model 3 providing the best fit.     

中国社会核算矩阵编制方法研究

 本文以联合国历次SNA标准为基础,设计了两种形式的社会核算矩阵,采用“bottom-up”的编表模式构建了中国2007年社会核算矩阵Ⅰ型表和Ⅱ型表。提出并采用了“分项平衡法”,对初始矩阵中所有不平衡项目进行逐项处理,实现了整个社会核算矩阵的总体平衡,并将调整结果与国际上常用的“交叉熵”方法结果进行了比较。     

C#和Java矩阵相乘运算性能比较

本文对当今最主流的两种编程语言C#和Java进行了对比研究,就其可移植性和运算速度两方面特性作了分析,这样的研究结果有助于更深刻地了解两种语言的特性,并且通过矩阵相乘的运算,对两种语言编写的程序性能进行了定量的评估。比较结果说明Java的运算性能更好,而且随着矩阵尺寸的增加,Java在性能方面的优势更加明显。     

一种新的空间权重矩阵选择方法

空间权重矩阵选择问题一直是空间计量经济学中的一个难题,权重矩阵的选择正确与否关系到模型的最终估计结果。本文在空间滞后模型框架下,把空间权重矩阵选择问题转化为变量选择问题,然后利用CWB方法进行变量选择。中国城市服务业集聚机理实证研究显示,利用本文所提出的方法所选取的空间权重矩阵较为合理,进而可以减少因为空间权重矩阵误设问题而引起的模型估计偏误。在大样本情形下,该方法可以非常有效地降低计算成本。     

Proportional hazards model for competing risks data with missing cause of failure

We consider the semiparametric proportional hazards model for the cause-specific hazard function in analysis of competing risks data with missing cause of failure. The inverse probability weighted equation and augmented inverse probability weighted equation are proposed for estimating the regression parameters in the model, and their theoretical properties are established for inference. Simulation studies demonstrate that the augmented inverse probability weighted estimator is doubly robust and the proposed method is appropriate for practical use. The simulations also compare the proposed estimators with the multiple imputation estimator of Lu and Tsiatis (2001). The application of the proposed method is illustrated using data from a bone marrow transplant study.     

低碳经济下企业生存的组织结构优化研究

红皇后理论研究了竞争逻辑变化下企业的生存与发展,证明了竞争对企业生存力的重要意义,特别强调了近期竞争经验对企业的正面作用。低碳经济给企业所处环境和竞争规则带来变化的同时,也带来了新的竞争逻辑。通过结合研究资源基础理论和组织理论,将环境职能部门交叉在其他部门流程中组成新的矩阵式组织结构,并将该结构通过红皇后理论加以验证。这种用组织创新来迎接新经济时代挑战的方式,是企业在低碳环境下提高自身竞争力的一种有效手段。     

Identification of Protective Actions to Reduce the Vulnerability of Safety-Critical Systems to Malevolent Intentional Acts: An Optimization-Based Decision-Making Approach

An empirical classification model based on the Majority Rule Sorting (MR-Sort) method has been previously proposed by the authors to evaluate the vulnerability of safety-critical systems (in particular, nuclear power plants [NPPs]) with respect to malevolent intentional acts. In this article, the model serves as the basis for an analysis aimed at determining a set of protective actions to be taken (e.g., increasing the number of monitoring devices, reducing the number of accesses to the safety-critical system) in order to effectively reduce the level of vulnerability of the safety-critical systems under consideration. In particular, the problem is here tackled within an optimization framework: the set of protective actions to implement is chosen as the one minimizing the overall level of vulnerability of a group of safety-critical systems. In this context, three different optimization approaches have been explored: (i) one single classification model is built to evaluate and minimize system vulnerability; (ii) an ensemble of compatible classification models, generated by the bootstrap method, is employed to perform a “robust” optimization, taking as reference the “worst-case” scenario over the group of models; (iii) finally, a distribution of classification models, still obtained by bootstrap, is considered to address vulnerability reduction in a “probabilistic” fashion (i.e., by minimizing the “expected” vulnerability of a fleet of systems). The results are presented and compared with reference to a fictitious example considering NPPs as the safety-critical systems of interest.     

《MATLAB-PC》矩阵分析计算软件包在控制理论中的应用

《MATLAB-PC》矩阵计算软件包是将瑞士苏黎世高等工业学校的《MATLAB-VAX》移植到IBM-PC机上后得到的。其功能包括通常的矩降运算,对称和非对称特征值问题,直至相当复杂的矩阵运算,如奇异值分解等。本文主要介绍用MATLAB实现的几种控制算法。结果表明,用MATLAB进行控制系统计算机辅助设计和计算、实现系统仿真极为简单方便,是进行计算机辅助设计和分析强有力的软件工具。