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本文应用商品的平均收益率、风险损失率,建立了零售业投资优化模型,再通过选择偏好系数,对风险进行控制。并将模型应用于一中型城市的大型购物商场,给出了该商场的最优投资组合。 相似文献
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董晓芳 《宁夏师范学院学报》2005,26(6):80-84
研究了不允许卖空条件下有交易成本的证券组合选择问题，给出了一个多目标证券组合选择模型，又通过引进风险偏好因子转化为单目标优化模型．再次利用曩优化理论转化为线性规划问题借助SAS软件求解，最后给出了一个算例说明该投资模型的可行性． 相似文献
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介绍了设计变量的许用离散集不同的离散变量结构优化设计问题的定界组合算法及其软件系统。根据静定化假设，给出了离散变量结构优化问题的数学模型，该模型实际上是一个组合优化问题，定界组合算法被用来求解该模型。给出了此算法的通用软件，利用Microsoft Visual C 6．0在Microsoft Window 2000 Professional下进行程序设计，实现了既可求解一般离散变量的线性规划问题，又能进行杆系结构优化的工具软件。软件也实现了用遗传算法求解离散变量结构优化设计，用户可以选择计算所用的算法。 相似文献
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对多目标证券组合投资模型进行了研究，模型以风险损失率作为风险。该模型是一多目标线性优化问题．我们采用模糊折衷算法对模型进行了求解，算例给出了该模型的一个实例的最优解。 相似文献
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本文给出了政府支出与税收决定的多目标决策的基本摸型和调控模型，基于这个模型，对政府支出和税收进行了调控分析。 相似文献
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应用H∞优化控制理论，提出了股市中庄家的操盘及其风险抵御问题，得出了考虑来自多种不定因素干扰的庄家品格肋动态模型和风险评价模型，给出了庄家在炒作中的风险抵御策略。 相似文献
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探讨了一类基于某种时态约束的周期时态关联规则的有关问题．首先，引入了时态型的定义以及相关的概念．然后，给出了一种时态事件模型，用以描述基于时态型的不同属性的各种状态的事件，同时定义了一类事件问的周期时态关联规则，它能在诸如股票波动、天气预报、商品销售等领域提供短期的预测和决策．最后，给出了发现此类周期时态关联规则算法的主要步骤，并且给出了对股票数据挖掘的实验结果分析． 相似文献
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类之间参量正确及时地传递是面向对象程序设计系统中的一个很重要的问题.通过对Java1.1的事件处理委托模型及相关概念的本质分析,得出了实现在不同类之间进行参量实时传递的几种实用方法,对给出几种参量实时传递方法的特点进行了比较分析.详细阐述了创建自己所需Listener的一般方法,并简要给出了实现例程. 相似文献
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Due to e-business's variety of customers with different navigational patterns and demands, multi-class queuing network is a natural performance model for it. The open multi-class queuing network(QN) models are based on the assumption that no service center is saturated as a result of the combined loads of all the classes. Several formulas are used to calculate performance measures, including throughput, residence time, queue length, response time and the average number of requests. The solution technique of closed multi-class QN models is an approximate mean value analysis algorithm (MVA) based on three key equations, because the exact algorithm needs huge time and space requirement. As mixed multi-class QN models, include some open and some closed classes, the open classes should be eliminated to create a closed multi-class QN so that the closed model algorithm can be applied. Some corresponding examples are given to show how to apply the algorithms mentioned in this article. These examples indicate that multi-class QN is a reasonably accurate model of e-business and can be solved efficiently. 相似文献
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In signal detection rater models for constructed response (CR) scoring, it is assumed that raters discriminate equally well between different latent classes defined by the scoring rubric. An extended model that relaxes this assumption is introduced; the model recognizes that a rater may not discriminate equally well between some of the scoring classes. The extension recognizes a different type of rater effect and is shown to offer useful tests and diagnostic plots of the equal discrimination assumption, along with ways to assess rater accuracy and various rater effects. The approach is illustrated with an application to a large‐scale language test. 相似文献
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Bromley H. Kniveton 《Educational studies》2004,30(3):331-343
The perceptions of mainstream teachers and parents of other children, and ‘significant others’, are crucial to the extent to which children with difficulties are accepted in mainstream classes. This study examined the views of 507 ‘significant others’ towards the inclusion of children experiencing a variety of difficulties. They were asked to rank how they felt about children with certain types of ‘difficulty’, and given the opportunity to explain their decisions in a subsequent interview. Five main issues were examined, namely the most suitable age for inclusion, the problems faced by parents, the type of difficulty most suitable for inclusion into mainstream classes, the allocation of resources and how resources should be allocated to children with different types of giftedness. Views towards these issues varied depending on the type of difficulty the child experienced. The findings of this study indicate that some children are more likely than others to be readily accepted by ‘significant others’ for inclusion into mainstream schooling. It is stressed that the perceptions of these ‘significant others’ impact upon how successful any attempt to include children in mainstream classes will be. 相似文献
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郑琰 《临沂师范学院学报》2007,29(3):15-18
利用锥理论和半序方法,对Banach空间上一类二元算子方程组的求解进行了探讨,利用较简捷的条件,得出方程组的唯一解及其迭代逼近式及误差估计式,并推广到n元算子方程组的情形,改进了许多有关结果. 相似文献
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郑琰 《临沂师范学院学报》2006,28(3):11-15
利用锥理论和单调迭代方法,本文在Banach空间对一类二元算子方程组的求解进行了探讨,利用较简捷的务件,得出方程组的最小最大解和最大最小解,及其上下控制逼近式．并推广到n元算子方程组的情形,改进了许多有关结果． 相似文献
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陈志恩 《宁夏师范学院学报》2010,31(6):14-17
介绍了两个目标类的决策信息系统中各目标类的Bayes粗糙集模型,并将这一模型推广到具有多目标类的情形.最后讨论了该模型的相关性质,计算实例表明该模型是有效的. 相似文献
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A latent variable modeling procedure for examining whether a studied population could be a mixture of 2 or more latent classes is discussed. The approach can be used to evaluate a single-class model vis-à-vis competing models of increasing complexity for a given set of observed variables without making any assumptions about their within-class interrelationships. The method is helpful in the initial stages of finite mixture analyses to assess whether models with 2 or more classes should be subsequently considered as opposed to a single-class model. The discussed procedure is illustrated with a numerical example. 相似文献
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英语写作教学写前阶段教师的角色转换 总被引：1，自引：0，他引：1
杨烁 《重庆第二师范学院学报》2007,20(2):87-90
大学英语写作教学改革中重要的一环就是写前阶段教师的角色转换。在对高校英语专科学生的问卷分析和访谈中,可以看出教师采取以学生为中心,交互式的教学方法,课堂教学以范文图解和主题辩论为主要形式,教师根据学生的语言认知和学习特征灵活地调整教学内容和进度,不受教材桎梏,就能有效开发学生的写作潜能,不断提高学生英语写作的水平和兴趣。 相似文献
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Hildur Ve Henricksen 《Interchange》1981,12(2-3):151-164
Conclusion In this paper, I have presented a model with very few nuances. My object has been to explore the most typical differences between the social classes and, therefore, I have not commented upon the situation of the lower-middle classes; nor have I given much attention to boys in bourgeois categories. My reason for this is that this special category has very often been the focus of socialization research. Rather I have tried to throw some light upon the socialization of working-class girls, where the concept of familism and of solidarity has been important in my analysis.However, the insights and thought patterns of boys and men in bourgeois categories must, in the same way as those of other social groups, be understood as a consequence of capitalism as a social system — and also be understood within a dialectical frame of reference. In other words, while boys in bourgeois categories are socialized in a way which often makes it possible for them to gain the most sought-after positions in society, they have to suffer certain disadvantages that may be costly for themselves as individuals and for society as a whole.My intention has been to discuss some relationships between socialization and the societal model of production. In a capitalist society, there is a need for some boys to be socialized into the elite and for some girls to be socialized into the reserve army of workers. The cause of women's liberation (as well as men's liberation) may be served in many ways and on many different levels. To me it seems especially important to understand the underlying societal forces that shape the roles of working-class girls and women. 相似文献