基于模糊多属性群决策的维护方式选择研究

维护方式选择是维护管理中的重要工作之一,合理的维护方式既能达到保障设备的稳定运行,又能同时兼顾其它各个方面的要求.由于对维护方式的评价涉及多个部门、人员和属性,有些指标只是一个模糊的概念,因而采用模糊多属性群决策的方法对维护方式进行优先抉择.本文结合A公司的设备维护方式选择问题,尝试使用模糊多属性群决策折衷算法求解最佳...     

用神经网络对开式冷挤压极限变形程度的预测

给出了基于 BP网络的极限变形程度预测的分析方法 ,得到了开式冷挤压εmax神经网络计算结果 ,与实验结果比较 ,其精度较高 ,证明了神经网络模型在开式冷挤压工艺中应用的可行性。     

我国液化天然气标准的现状和展望

探讨了我国有关液化天然气（LNG）标准的现状,并提出了现有LNG标准体系的不足;参考我国天然气标准化技术委员会的制标计划．提出了对LNG标准的展望。     

智能安全气囊高坠防护空调服的设计研究

施工现场智能安全防护空调服属人体安全防护范畴,通过将安全气囊、电子控制元件、气瓶、导通装置嵌入到施工安全马甲中,设计了SHW12、SHW13、SHW22三款防护服并对囊袋触发灵敏度,囊袋的厚度、重量、断裂强度、断裂伸长率、撕裂强力、燃烧速率等性能进行检测。同时将制冷系统巧妙地集成在防护服内,在施工现场进行穿戴试验,找出控制单元中算法模块参数进行优化,并对加速度、角速度的六轴采集波形进行叠加合成经滤波器处理。通过一系列的试验证明,防护服具有良好的缓冲消能作用,对意外事故发生时的作业人员具有很好的保护作用。     

以企业文化为导向的星级酒店CRM的实证研究

酒店业的高速发展以及顾客的期望值不断提高,如何利用CRM系统来提升客人的满意度,以达到提升酒店竞争力是酒店需要关注的,本文对客户关系管理(CRM)理论研究和国内星级酒店CRM中存在的问题进行分析,最后以三亚丽思卡尔顿酒店基于企业文化创建的CRM系统值得我国国内酒店学习和借鉴。     

不确定环境下的地震应急救援路径优化研究

针对地震应急救援的特点,引入不确定理论,在地震灾害的背景下,研究震后动态网络环境下的应急救援路径选择问题。用不确定变量表示网络中各路段的破坏程度,综合考虑路径破坏程度及车辆路径连续性等约束条件,以救援时间最短为目标,基于不确定理论建立了动态优化模型,并用改进的遗传算法求解,最后设计算例验证了模型和算法的有效性。     

Searching for empirical linkages between demographic structure and economic growth

Demographic structure could affect economic growth through many channels. However, little is known about how demographic structure affects economic growth since no study has examined an extensive collection of channels through which demographic structure could affect economic growth in a single context. This paper overcomes this limitation by examining 45 potential mediating variables between demographic structure and economic growth. A causal search algorithm is used to identify channels through which demographic structure affects economic growth. Our results suggest that demographic structure affects economic growth differently between developed and developing countries. For developed countries, we find that an increase in the share of middle-aged workers has a positive effect on economic growth through institutions, investment and education channels. On the other hand, an increase in the share of the senior population has a negative effect on economic growth through institutions and investment channels. For developing countries, we find (but with weak evidence) that an increase in the share of young workers has a negative effect on economic growth through investment, financial market development and trade channels.     

上市公司“MD&A”信息质量评价模型——基于政府监管的视角

管理层讨论与分析(Management’s Discussion and Analysis,MDA)作为财务报表的有益补充,因其能够有助于增强信息披露的针对性和有效性而越来越受到信息使用者的关注。针对我国MDA信息质量不高的现状和评价体系不尽完善的情况,总结和吸收前人的研究成果,合理界定MDA信息质量特征。在此基础上,充分考虑MDA信息的生成机制和外部评价结果,采用层次分析法,构建适合我国上市公司MDA信息质量评价模型。     

基于成本优化的制造业生产物流装配线排序问题分析

为了降低制造业的生产成本，提高收益，在分析生产物流配线闲置和超载成本的基础上，采用粒子群算法对其进行优化，并利用模糊自适应改进惯性权值，通过实证研究表明该方法实用，可操作性强，可以有效降低制造业生产物流成本，具有广泛的应用价值。     

Numerical Maximisation of Likelihood: A Neglected Alternative to EM?

There is by now a long tradition of using the EM algorithm to find maximum‐likelihood estimates (MLEs) when the data are incomplete in any of a wide range of ways, even when the observed‐data likelihood can easily be evaluated and numerical maximisation of that likelihood is available as a conceptually simple route to the MLEs. It is rare in the literature to see numerical maximisation employed if EM is possible. But with excellent general‐purpose numerical optimisers now available free, there is no longer any reason, as a matter of course, to avoid direct numerical maximisation of likelihood. In this tutorial, I present seven examples of models in which numerical maximisation of likelihood appears to have some advantages over the use of EM as a route to MLEs. The mathematical and coding effort is minimal, as there is no need to derive and code the E and M steps, only a likelihood evaluator. In all the examples, the unconstrained optimiser nlm available in R is used, and transformations are used to impose constraints on parameters. I suggest therefore that the following question be asked of proposed new applications of EM: Can the MLEs be found more simply and directly by using a general‐purpose numerical optimiser?