一种基于模糊推理的因素权重确定方法

在模糊综合评价中,如何确定因素的权重是非常重要的,也是非常困难的,它直接关系到评价结果的合理性与真实性.利用模糊推理技术,提出了一种基于模糊推理的因素权重确定方法,其利用人们处理复杂问题的逻辑思维方式,建立评价空间和单位评价空间的映射,得到模糊关系方程并用于确定因素的权重.实验结果表明,利用该模型得到的权重能反映各因素的重要性,用其对待评对象进行模糊综合,其结果也是合理的.     

基于最优组合赋权法的我国能源效率评价及影响因素研究

本文总结我国能源效率的主要影响因素,具体包括产业结构、技术进步、能源消费结构、经济发展水平、市场化程度和开放程度,构建我国能源效率影响因素的指标体系。基于最优组合赋权法建立能源效率评价模型,并对2000~2011年我国能源效率及影响因素进行实证分析。实证结果表明:我国能源效率整体呈上升趋势,能源效率显著提高;第二产业产值占国内生产总值比重、重工业占工业产值比重、第二产业增长值比重、R&D投入、第三产业产值占国内生产总值比重和煤炭消费量占能源消费总量比重是我国能源效率最主要的影响指标,而天然气消费量占能源消费总量比重和水、核、风消费量占能源消费总量比重对我国能源效率影响相对较小。     

影响收益的公司指标在最优投资组合选择中的应用

如何从数目巨大的市场股票集中选取一组特定的股票作为最优投资组合选择模型的输入,以确保最终的投资方案具有优异而稳定的表现一直是投资理论界和实务界关注的重点.为此,本文基于作者新近结合中国股市特性并采用新方法所确定影响中国股票收益的多个公司基本特性指标,设计了一个恰当的股票预选策略,并由此导出了新型而稳健的投资组合选择两阶段法.实证结果表明新方法能使投资者便捷地找到更稳健的投资策略.     

城市效率及其影响因素——基于东北三省34个城市的比较分析

改革开放30多年来,中国的城市化进程不断加快.然而,城市的效率问题缺少广泛的关注.选取土地投入量、资本投入量、劳动投入量、技术投入量和信息投入量5项输入指标,选取城市经济总量(GDP)、城市投入的收益情况(财政收入)2项输出指标,通过构建指标体系,运用DEA中可变规模收益(VRS)模式下的BCC模型,对东北三省34个地级以上城市的效率及其影响因素进行了分析.研究结果表明,东北三省各城市的效率参差不齐,有待进一步提高.城市效率与资本、土地、劳动力、信息化水平呈正相关关系.因此,城市效率的提高和城市的协调发展需协调好投入要素的比例关系.     

带交易费的最优投资组合选择的极大极小方法

研究不允许卖空时不相关资产的最优投资选择问题.在风险资产收益率不能确切知道的情况下,建立了投资组合选择问题的极大极小模型.将交易费引入到极大极小模型中,交易费假定为新旧投资组合之差的V型函数.推导出有效投资组合与有效前沿的解析表达式.     

选择资产组合的EP-MV模型及最优解的解析表示

本文提出了存在无风险资产贷出或借入时的有效投资组合模型(EP-MV模型)，研究了不允许卖空(投资比例非负)约束条件下，EP-MV优化模型的算法，给出了有效投资组合投资比例的解析表示．在资产收益由多因素模型产生的基础上，得到了资产与有效投资组合的期望收益及风险的估计，便于实际应用．     

“城市让生活更美好”的验证及影响因素分析

上海世博会"城市让生活更美好"的主题具有丰富的内涵,城市居民的生活美好水平可通过与周边乡村居民的生活比较进行测量,其影响因素有富裕、和谐、美化、安全等。在设计生活美好指数评价指标和影响因素测量指标的基础上,构建指数测量和影响因素分析的二阶段模型,并以2007年中国31省市的地市级城市的截面数据为样本,采用改进的模糊积分和格兰杰检验方法进行实证分析,得出"城市让生活更美好"命题成立,而对城市美好生活具有重要有利影响的因素主要是城市和谐、城市美化、城市开放和城市进步的结论。     

制造商检验的最优质量水平及影响因素研究

为提高我国食品质量安全水平,对小型、分散的单个供应商和一个制造商构成的食品供应链中,制造商对原材料和最终食品进行质量检测的情况,建立了以供应商和制造商各自的质量水平为决策变量的优化模型,分析了最优质量水平的影响因素和影响效应.并依据结论提出相应建议,如提高消费者对优劣食品的识别能力,发挥制造商在供应链中的监督检验作用等.     

影响高考成绩的多因素权重分析

高考考题逐渐从"知识立意"转向"素质立意",突出了对考生综合能力水平的检测影响高考成绩的因素众多,针对现有研究缺少了将影响高考成绩众多因素进行整体分析这一问题,首先构建了高考成绩的影响因素模型,利用层次分析法确定各因素的权重,将各影响因素对高考成绩的相对重要程度进行排序,并给出了相关教学建议,为学生家长及教师正确引导学生备考提供理论指导,促进高考自身的良性发展并发挥了对素质教育的正面导向作用.     

固定消费/收入模型下的M-V最优投资组合选择

本文研究了一个有固定消费/收入现金流的连续时间的最优投资组合选择问题.把投资者的财富用分离的思想来考虑.将投资者的财富分成两部分,消费/收入部分和投资部分,从而将原问题转化为不含消费/收入现金流的M-V投资组合选择的辅助问题.证明了辅助问题的最优投资策略就是原问题的最优策略,得到了原问题的最优策略及有效前沿并分析了消费/收入对投资的影响.     

一种时序多属性高技术产品性能的评价方法

本文针对时序多属性高技术产品的特点,提出用首用时间描述综合性能的思想,给出其性能评价方法及评价模型,运用实际样本资料给出算例。     

Quotients of partial abelian monoids and the Riesz decomposition property

Partial abelian monoids (PAMs) are structures (), where is a partially defined binary operation with domain , which is commutative and associative in a restricted sense, and 0 is the neutral element. PAMs with the Riesz decomposition properties and binary relations with special properties on PAMs are studied. Relations with abelian groups, dimension equivalence and K ₀ for AF C^*-algebras are discussed. Received September 17, 2000; accepted in final form March 13, 2002.     

On some ‘duality’ of the Nikodym property and the Hahn property

Drewnowski and Paúl proved in [L. Drewnowski, P.J. Paúl, The Nikodým property for ideals of sets defined by matrix summability methods, Rev. R. Acad. Cienc. Exactas Fís. Nat. (Esp.) 94 (2000) 485-503] that for any strongly nonatomic submeasure η on the power set P(N) of N the ideal Z(η)={N∈P(N)|η(N)=0} has the Nikodym property (NP); in particular, this result applies to densities dA defined by strongly regular matrices A. Grahame Bennett and the authors stated in [G. Bennett, J. Boos, T. Leiger, Sequences of 0's and 1's, Studia Math. 149 (2002) 75-99] that the strong null domain ₀|A| of any strongly regular matrix A has the Hahn property (HP). Moreover, Stuart and Abraham [C.E. Stuart, P. Abraham, Generalizations of the Nikodym boundedness and Vitali-Hahn-Saks theorems, J. Math. Anal. Appl. 300 (2) (2004) 351-361] pointed out that the said results are in some sense dual and that the last one follows from the first one by considering the density dA (defined by A) as submeasure on P(N) and the ideal Z(dA) as well by identifying P(N) with the set χ of sequences of 0's and 1's. In this paper we aim at a better understanding of the intimated duality and at a characterization of those members of special classes of matrices A such that Z(dA) has NP (equivalently, ₀|A| has HP).     

On the Cayley-Bacharach property and the construction of vector bundles

We study the Cayley-Bacharach property on complex projective smooth varieties of dimension n≥2 for zero dimensional subscheme defined by the zero set of the wedge of r-n + 1 global sections of a rank r≥n vector bundle,and give a construction of high rank reflexive sheaves and vector bundles from codimension 2 subschemes.     

Invertibility and the fredholm property of difference operators

We obtain conditions for the invertibility and the Fredholm property of the difference operator (Dx)(n)=x(n) -U(n)x(n − 1),n ε ℤ, in the Banach space l _p (ℤ, X),p ε [1, ∞], of vector sequences, whereX is a Banach space andU is a bounded operator function. Translated fromMatematicheskie Zametki, Vol. 67, No. 6, pp. 816–827, June, 2000.     

Some weak fragments of Martin’s axiom related to the rectangle refining property

We introduce the anti-rectangle refining property for forcing notions and investigate fragments of Martin’s axiom for ℵ₁ dense sets related to the anti-rectangle refining property, which is close to some fragment of Martin’s axiom for ℵ₁ dense sets related to the rectangle refining property, and prove that they are really weaker fragments. T. Yorioka was partially supported by Grant-in-aids for Scientific Research No.16340022 and No.18840022.     

Distortion and stability of the fixed point property for non-expansive mappings

Let X be a Banach space. We say that X satisfies the fixed point property (weak fixed point property) if every non-expansive mapping defined from a convex closed bounded (convex weakly compact) subset of X into itself has a fixed point. We say that X satisfies the stable fixed point property (stable weak fixed point property) if the same is true for every equivalent norm which is close enough to the original one. Denote by P(X) the set formed by all equivalent norms with the topology of the uniform convergence on the unit ball of X. We prove that the subset of P(X) formed by the norms failing the fixed point property is dense in P(X) when X is a non-distortable space which fails the fixed point property. In particular, no renorming of ?₁ can satisfy the stable fixed point property. Furthermore, we show some examples of distortable spaces failing the weak fixed point property, which can be renormed to satisfy the stable weak fixed point property. As a consequence we prove that every separable Banach space can be renormed to satisfy the stable weak fixed point property.