An investigation of transformation-based prediction interval for the Weibull median life

Statistical inference based on the Weibull distribution, a distribution widely used in reliability and survival analysis, is usually difficult as it often involves numerical computation and approximation. However, this distribution can be transformed to near-normality by a simple power transformation. Based on this transformation, a prediction interval (PI) for its median can be easily constructed through an inverse transformation. The procedure for selecting the best power transformation through minimizing Kullback-Leibler information is described. The property of this transformation-based PI is investigated. Simple correction factors are also proposed. It is shown that the transformation-based PI with corrections performs well, irrespective of the sample size and parameter values. Simulation results show that the new PI generally outperforms the existing PI. Numerical examples are given for illustration.     

施工项目的成本控制--信誉付款

施工企业的资金大都匮乏，由此对施工项目的管理带来了一定的困堆，同时也带来了一定的风险，如何进行施工项目的成本管理，如何降低施工项目管理的风险一直是施工企业管理者关注的问题。     

Binary effectivity rules

A social choice rule (SCR) is a collection of social choice correspondences, one for each agenda. An effectivity rule is a collection of effectivity functions, one for each agenda. We prove that every monotonic and superadditive effectivity rule is the effectivity rule of some SCR. A SCR is binary if it is rationalized by an acyclic binary relation. The foregoing result motivates our definition of a binary effectivity rule as the effectivity rule of some binary SCR. A binary SCR is regular if it satisfies unanimity, monotonicity, and independence of infeasible alternatives. A binary effectivity rule is regular if it is the effectivity rule of some regular binary SCR. We characterize completely the family of regular binary effectivity rules. Quite surprisingly, intrinsically defined von Neumann–Morgenstern solutions play an important role in this characterization.     

基于仿真技术的物流中心站台数确定方法研究

通过建立描述站台数量的模型,利用排队论理论得到了最优站台数的解法,同时利用Arena仿真软件对这一问题进行仿真。应用Arena仿真克服了理论建模方法的不足,为物流中心最优站台数问题提供了一种较为理想的解决方法。     

工程项目投标阶段的风险决策方法研究

文章根据工程项目投标阶段风险决策的内容和特点，在考虑纯风险和投机风险的基础上，从单项风险入手，运用区间数和区间概率的性质，先描述各个风险要素，然后进行单项风险对策间的对比择优，并将其结果对应于方案、进度、成本费用及投标报价总风险补偿费的确定，最终实现承包商的风险成本最小化。     

基于模糊层次分析法的企业人力资源风险因素评价

文章结合三角模糊数和层次分析法,以企业外部环境、内部环境及人力资源个人3个方面的11个因素为指标体系,建立模糊层次分析模型,采用三角模糊数表示专家的判断信息,加权平均综合多名专家意见,利用层次分析法对专家判断结果进行处理从而得出各个评价因素的相对权重的大小,并举例说明了模型的应用。     

基于Fuzzy层次分析法的CPFR评价体系研究

CPFR是一种协同式的供应链库存管理技术,建立在JMI和VMI的最佳分级实践基础上,能同时降低分销商的存货量,增加供应商的销售量。在深入研究了CPFR模型及内部结构的基础上,利用先进的Fuzzy-AHP方法对CPFR进行了评价体系模型的构建。基于新方法的评价结果比原有的经典方法更准确、更人性化,对于解读和应用CPFR技术具有重要的现实意义。     

How many voters are needed for paradoxes?

Summary. This paper presents a general procedure for finding profiles with the minimum number of voters required for many important paradoxes. Borda's and Condorcet's classic examples are revisited as well as generalizations. Using Saari's procedure line, we obtain an upper bound for the minimum number of voters needed for a profile for which the Condorcet winner is not strictly top ranked for all weighted positional procedures. Also we give a simple upper bound on the minimum number of voters needed for a set of prescribed voting outcomes. In contrast to situations wherein small numbers of voters are needed, we consider paradoxes requiring arbitrarily large numbers of voters as well as large numbers of alternatives. Finally we indicate connections with statistical rank based tests. Received: April 18, 2001; revised version: May 25, 2001     

拆分招标的供应商数量研究

许多企业在采购时,常常将整笔业务拆分为两个合同:较大的第一合同和较小的第二合同,通过分批二级价格封闭式招标来选择不同的供应商供货。本文通过建立分批招标模型分析了供应商的投标策略和买方的采购策略,得出了当参加第一合同竞标的供应商数目和第二合同新引入的供应商数目满足一个不等式时,拆分招标的采购成本小于整体招标的采购成本,并且指出了拆分比例对拆分招标的采购成本的影响。     

总量均衡区间与宏观调控应确立的若干新原则

现代市场经济条件下,供给方调整其生产规模所需的成本可称为调节成本。由于存在调节成本,传统分析中的“总量均衡中心点”两侧便分别存在着“低位临界点”与“高位临界点”,这两点界定了一个特殊的“总量均衡区间”。“总量均衡区间”的出现对宏观调控将产生诸多重要影响,使之面临一系列新问题、新挑战。为有效应对这种新情况,在宏观调控实践中有必要相应地确立“近似均衡原则”、“适度超前原则”、“临界点原则”、“供给方原则”。