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1.
通过对中国各大城市不同类型的企业调查分析,运用多变量统计分析模型,对各行业的电子商务综合规范需求及差异进行了对比分析,利用统计分析结果剖析其原因与关键问题,最后提出若干合理化建议.  相似文献   

2.
根据2008年广东省不同收入等级城镇居民的人均消费构成的统计数据,采用对应分析法,并结合可支配收入、平均消费倾向分析不同收入等级城镇居民的消费特征.针对不同的收入人群提出了不同的扩大内需措施的政策建议.  相似文献   

3.
The first order local influence approach is adopted in this paper to assess the local influence of observations to canonical correlation coefficients, canonical vectors and several relevant test statistics in canonical correlation analysis. This approach can detect different aspects of influence due to different perturbation schemes. In this paper, we consider two different kinds, namely, the additive perturbation scheme and the case-weights perturbation scheme. It is found that, under the additive perturbation scheme, the influence analysis of any canonical correlation coefficient can be simplified to just observing two predicted residuals. To do the influence analysis for canonical vectors, a scale invariant norm is proposed. Furthermore, by choosing proper perturbation scales on different variables, we can compare the different influential effects of perturbations on different variables under the additive perturbation scheme. An example is presented to illustrate the effectiveness of the first order local influence approach.  相似文献   

4.
本文以449家制造业上市公司2002-2011十年的数据为样本,以企业生命周期为视角,对不同发展时期企业的社会责任进行了组内及组间的比较分析。研究结果显示,企业处于不同生命周期时,社会责任履行的侧重点是不同的;并且,对股东的责任和对债权人的责任会随着生命周期的不同而呈现出差异性。  相似文献   

5.
This paper presents a method for comparing the sensitiveness of people to different possible options for the route of High Voltage transmission lines. It has been tested on practical cases.First, we create special dimensions and scales in order to evaluate the different zones of a studied area. Then, the different options for the route of HV lines (which are a succession of different zones) have to be compared.The construction of criteria permitting the comparison of different options raises a theoretical issue: how to punctualise the geographic distribution or the grades of the different zones of an option, in order to reflect preferences? Different methods of punctualisation are proposed which could apply to other cases. But the purpose of the paper is merely to show that these methods of punctualisation are not neutral, they cannot reflect all the characteristics of a distribution of grades.  相似文献   

6.
本文讨论一种合理的绿色机房模型,求出了在不同的任务量、分配方式、空调风速和空调温度下机房的平均温度、热点、以及热分布和气流速度分布图。分别用人工神经网络和模拟仿真软件Airpak 软件建立模型分析空调的热分布。通过在Airpak中更改机柜发热功率、空调的送风温度、送风速度来模拟仿真不同情况下机房的热循环过程。最后进行改进和优化,使其能够适应更多情况和条件。  相似文献   

7.
顾及降雨及温度因子的卡尔曼滤波模型   总被引:1,自引:0,他引:1  
考虑到处于不同位置的滑坡变形监测点,由于它们所处的位置不同,各种环境因素对它们的影响及影响程度也不同,因此它们的变形规律也不同.首先通过计算比较找出剩余标准差最小的变形与时间、大气降雨量、温度相关关系的单因子模型,再将这些单因子模型通过叠加,组成多因子模型,然后将变形与时间、大气降雨量、温度相关关系的多因子模型的模型参数看作含有动态噪声的状态向量,建立卡尔曼滤波模型.实例计算表明这种建模方法效果较好.  相似文献   

8.
This paper concerns reaction–diffusion systems consisting of three or four equations, which come out of reversible chemistry. We introduce different scalings for those systems, which make sense in various situations (species with very different concentrations or very different diffusion rates, chemical reactions with very different rates, etc.). We show how recently introduced mathematical tools allow to prove that the formal asymptotics associated to those scalings indeed hold at the rigorous level.  相似文献   

9.
An adaptive algorithm based on computational intelligence techniques is designed, developed and applied to the timetabling problem of educational organizations. The proposed genetic algorithm is used in order to create feasible and efficient timetables for high schools in Greece. In order to demonstrate the efficiency of the proposed genetic algorithm, exhaustive experiments with real-world input data coming from many different high schools in the city of Patras have been conducted. As well as that, in order to demonstrate the superior performance of the proposed algorithm, we compare its experimental results with the results obtained by another effective algorithm applied to the same problem. Simulation results showed that the proposed algorithm outperforms other existing attempts. However, the most significant contribution of the paper is that the proposed algorithm allows for criteria adaptation, thus producing different timetables for different constraints priorities. So, the proposed approach, due to its inherent adaptive capabilities, can be used, each time satisfying different specific constraints, in order to lead to different timetables, thus meeting the different needs that each school may have.  相似文献   

10.
In some biological experiments, it is quite common that laboratory subjects may be different in their patterns of susceptibility to a treatment. We need to determine the different patterns of susceptibility. In this paper we model the number of susceptibility's patterns and the parameters jointly, and base inference about these quantities on their posterior probabilities, making use of reversible jump Markov chain Monte Carlo methods that are capable of jumping between the parameter subspaces corresponding to different numbers of components in the mixture. For convenience, we always assume different patterns of susceptibility have common variances. The paper apply the methodology to the analysis of univariate normal mixtures with different variances. The practical significance of the proposed method is illustrated with a dose-response data set.  相似文献   

11.
由于学科的自身特点和统计源的学科结构特点,不同学科期刊具有显著差异。但由于期刊数量庞大,评价指标多种多样,很难从宏观上把握各学科期刊的整体特点,对学科间差异给出科学的判断。本文以SCI期刊为研究对象,用区间数据代表各学科期刊,采用因素区间数据PCA算法探寻反映期刊水平的关键指标,并利用区间数据投影的方式绘制主平面图,反映各学科期刊的整体特点及我国期刊在国际上的地位。  相似文献   

12.
拟协调元的位移函数及节点误差   总被引:2,自引:0,他引:2  
直接从拟协调元的应变关系式出发,构造具有明确物理意义的幂级数形式的位移函数,从而得出拟协调元的常应变和线性应变系数是唯一确定的,它只能收敛到常应变的结论;刚性位移项可采用多种构造方法,不同的方法得出的节点参数与单元的本身的节点参数存在不同阶次的误差,这与常规位移法有限元不同。  相似文献   

13.
首先指出了农村地区存在的信息化不平衡现象,并提出需要针对不同农户的禀赋特征研究他们的采纳行为.为了研究不同禀赋农户的采纳行为,结合层次聚类和K-均值聚类,根据学历、收入和农地大小将农户分为高禀赋和低禀赋两组,利用扩展的技术接受模型研究了不同禀赋农户对于短信定制服务的采纳行为.研究结果表明低禀赋农户更容易受到可试性、感知易用性和成本的影响,而主观规范、网络外部性和感知有用性对不同禀赋农户的影响并没有显著区别.  相似文献   

14.
The method of bifurcation of planar dynamical systems and method of numerical simulation of differential equations are employed to investigate the modified dispersive water wave equation. We obtain the parameter bifurcation sets that divide the parameter space into different regions which correspond to qualitatively different phase portraits. In different regions, different types of travelling solutions including solitary wave solutions, shock wave solutions and periodic wave solutions are simulated. Furthermore, with a generalized projective Riccati equation method, several new explicit exact solutions are obtained.  相似文献   

15.
In this article we focus on university lecturers’ approaches to the service teaching and factors that influence their approaches. We present data obtained from the interviews with 19 mathematics and three physics lecturers along with the observations of two mathematics lecturers’ calculus courses. The findings show that lecturers’ approaches to teaching the same topic vary across departments; that is, they consciously privilege different aspects of mathematics, set different questions on examinations and follow different textbooks while teaching in different departments. We discuss factors influencing lecturers’ decision of what (mathematics) to teach in different departments and offer educational implications for service mathematics teaching in terms of students’ mathematical needs and the role of mathematics for client students.  相似文献   

16.
对于中国这样一个因地区经济水平不同而造成地区消费差异极度巨大的国家,航空公司应该怎样设置卖票策略使自己的各个航班的效用最大,传统的方法是票价系统因地而异,但这种方法有很大的随意性,并且对订票系统改变较大,操作成本高。本文将采用一个新的方法讨论该问题。首先,引进一个反映地区消费水平的参数,简称地区因子。然后结合一个单阶段航班,建立考虑地区因子的随机动态模型,同时证明了与效用函数相关的一些性质:比例边际效用函数是分别关于时间,待订票数和地区因子的单调增加函数。基于这些性质,对连接不同地域的航班,我们只要调整地区因子,再采用阀值控制策略就能使航班的效用最大且空置率得到有效抑制。最后,给出了一个实例。  相似文献   

17.
关键链项目缓冲监控绩效受活动自身和活动执行主体特性的双重影响,项目经理应根据不同执行主体对活动进行差别监控,而现有缓冲监控研究未充分考虑活动执行主体异质性。首先,结合网络复杂度和风险感知等活动自身因素以及综合信任度等执行主体层面因素对缓冲进行分配;其次,引入容错机制对不同活动触发点进行差别设置,并将缓冲监控分为信任型和监督型两类监控模式;最后,根据活动缓冲消耗对不同活动进行差别动态监控。蒙特卡洛模拟结果表明,本文方法能够有效降低错误预警,保证项目按计划执行并实现对项目的综合优化。  相似文献   

18.
In this article, we study the boundedness of weighted composition operators between different vector-valued Dirichlet spaces. Some sufficient and necessary conditions for such operators to be bounded are obtained exactly, which are different completely from the scalar-valued case. As applications, we show that these vector-valued Dirichlet spaces are different counterparts of the classical scalar-valued Dirichlet space and characterize the boundedness of multiplication operators between these different spaces.  相似文献   

19.
如何促进军民合作技术创新是军民深度融合战略背景下军民双方亟需解决的重要问题。基于演化博弈的基本理论和方法,构建了包含民企、军企与政府在内的三方博弈模型,寻找出能使整个系统处于均衡状态的稳定策略,并利用数值仿真分析了政府支持不同方式对军民合作技术创新的影响。结果表明:在政府不同支持方式下,民企和军企相互促进,双方均向合作技术创新的方向演化,并最终保持稳定;随着时间的推进,政府最终均会选择退出支持,不同支持方式下退出速度不同;政府应对不同支持方式进行优化。  相似文献   

20.
By using the theory of planar dynamical systems to a compound KdV-type nonlinear wave equation, the bifurcation boundaries of the system are obtained in this paper. These bifurcation sets divide the parameter space into different regions, which correspond to qualitatively different phase portraits and therefore different types of the solutions may exist in different regions. The parameter conditions for the existence of solitary wave solutions and uncountably infinite, many smooth and non-smooth, periodic wave solutions are therefore obtained.  相似文献   

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