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.     

On the Role of Weight Restrictions in Data Envelopment Analysis

This paper examines the role that weight restrictions play in Data Envelopment Analysis (DEA). It is argued that the decision to include a factor (input or output) in a DEA model represents an implicit judgement that the factor has a non-trivial weight. It therefore seems perverse to allow DEA to assign a trivial weight to that factor in assessing the efficiency of a unit. There is therefore a strong case for imposing restrictions on factor weights. However, many existing methods of weight restriction are in practice unwieldy. This paper proposes an alternative approach we term contingent weight restriction which is both practical and intellectually consistent with the DEA philosophy. The paper explores the implications of alternative methods of weight restriction using simulated data from a well known production process.     

煤炭资源型城市聚集经济与城市化水平研究

运用可变权系数综合评价模型对2002年中国煤炭资源型城市城市化水平进行测度;基于1999～2002年度煤炭城市面板数据,应用随机效应模型估计煤炭城市聚集经济水平;结果表明,我国煤炭城市城市空间经济结构效率和其城市化水平并不具有正相关性,许多城市化水平相对较高的煤炭城市的聚集经济较差,并没有显示出城市化经济的优势.     

自适应聚类视角下学科领域主题分析——以物流学科为例

基于改进关键词重要性和近邻传播聚类算法,提出了一种学科领域主题分析方法,通过词频分析法和作者潜意识行为计算高频关键词权重,借助共词分析和Ochiai系数构建带权重高频关键词相似性矩阵,利用近邻传播聚类算法对学科领域主题进行自适应提取与分析。以CSSCI收录的2015—2019年物流学科领域期刊论文为研究对象,借助新方法对其进行主题分析,研究结果表明:高重要性的关键词不一定是核心主题,核心主题与同一簇内其它成员关键词最为相似。与此同时,近五年物流学科存在“降本增效”“区域物流一体化”“现代物流技术研究与创新”“物流体制改革与产业转型升级”“农村物流与农产品物流”“电子商务与跨境电商”“可持续发展理念”等七大热门主题。     

Evolution of momentum and popularity

In this paper, the evolutionary behavior of two types of investor in a capital market with two risky competing securities is investigated. It is shown that, if all investors are momentum-oriented, then only those who are the most sensitive to popularity will survive. Conversely, if all investors are popularity-oriented, then they will all invest in the same security.     

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”。     

中国绿色能源高质量发展水平测度研究

在"创新、协调、绿色、开放、共享"五大发展理念中,绿色协调发展成为关系中国可持续发展全局的重要理念,而绿色能源高质量发展是绿色高质量发展中的一个重要有机组成部分。本文构建了涉及绿色能源投资、生产、消费和减排4个系统的9个细化指标,利用熵权TOPSIS法实证测度2017年中国绿色能源高质量发展水平,并深入分析各区域之间的差异。通过研究发现:中国30个省区绿色能源高质量发展的水平在4个子系统和综合水平方面的表现均存在差异,综合水平总体呈现"东中部高且比较接近,而西部中等偏低"的区域分布格局;然后依照绿色能源高质量发展综合水平的高低,把30个省区划分为领先型、中等型和落后型3种类型。进而深入把握中国绿色能源高质量发展水平的区域分布规律,为统筹推进各省区协同提升中国绿色能源高质量发展水平提供较为可靠的依据。     

基于组合权的灰色关联分析在供电企业营销效果综合评价中的应用

在供电企业电力营销效果综合评价中,客观赋权法体现了指标的信息量,而主观赋权法体现了指标的价值量,综合评价应当体现二者的统一.针对电力营销效果评价,提出了基于组合权的灰色关联分析方法.对传统的灰色关联法进行改进,将该方法用于供电企业电力营销效果评价,得到了较好的结果.     

“机械制图用计算机信息交换制图规则”中的若干问题探讨

分析讨论了ＧＢ／Ｔ１４６６５－９３《机械制图用计算机信息交换、制图规则》中存在的问题与错误,并提出了相应的修正建议。     

Credibilistic risk aversion

In the probabilistic risk aversion approach, risks are presumed as random variables with known probability distributions. However, in some practical cases, for example, due to the absence of historical data, the inherent uncertain characteristic of risks or different subject judgements from the decision-makers, risks may be hard or not appropriate to be estimated with probability distributions. Therefore, the traditional probabilistic risk aversion theory is ineffective. Thus, in order to deal with these cases, we suggest measuring these kinds of risks as fuzzy variables, and accordingly to present an alternative risk aversion approach by employing credibility theory. In the present paper, first, the definition of credibilistic risk premium proposed by Georgescu and Kinnunen [Fuzzy Inf. Eng., 2013, 5, 399–416] is revised by taking the initial wealth into consideration, and then a general method to compute the credibilistic risk premium is provided. Secondly, regarding the risks represented with the commonly used LR fuzzy intervals, a simple calculation formula of the local credibilistic risk premium is put forward. Finally, in a global sense, several equivalent propositions for comparative risk aversion under the credibility measurement are provided. Illustrated examples are presented to show the applicability of the theoretical findings.