基于改进型主成分分析法的食品供应商评价模型研究

根据食品行业的特点建立供应商评价指标体系,利用改进型主成分分析法消除评价指标之间相关影响,减少指标选择的工作量,并通过专家打分及相关的评价指标建立判别模型对备选的供应商进行筛选,然后选择最优的供应商.最后通过实例分析验证了该方法的有效性,对企业选择物流供应商具有一定参考价值.     

基于改进型主成分分析法的食品供应商评价模型研究

根据食品行业的特点建立供应商评价指标体系，利用改进型主成分分析法消除评价指标之间相关影响，减少指标选择的工作量，并通过专家打分及相关的评价指标建立判别模型对备选的供应商进行筛选，然后选择最优的供应商。最后通过实例分析验证了该方法的有效性，对企业选择物流供应商具有一定参考价值。     

基于BP神经网络的供应商评价方法研究

供应链环境下供应商评价需要从技术、协作、服务等多方面进行评估,其实质是一个多目标决策问题。神经网络评价系统将供应商关键指标数据作为输入向量,将实际的专家综合评价指标作为输出评价,经过学习训练后,评价系统可以自动给出客观公正的评价结果。采用神经网络,不仅提高了供应商评价的科学性,也为进行动态评价提供了决策支持。     

基于层次分析法的中间合金供应商评价

本文根据某公司对某类中间合金的采购情况,结合中间合金采购中常见的问题,运用层次分析法对中间合金供应商的评价方法进行了研究.将中间合金供应商的评价指标进行分析并赋予量化权重,构建了供应商评价模型,然后运用该模型对该公司近三年采购情况对供应商进行打分,根据评价结果给出未来供应商选择的建议.     

基于SE-DEA的第三方物流服务供应商的评价选择

本文采用SE-DEA方法解决第三方物流供应商的评价选择问题,克服了以往常用的评价方法在确定权重方面的不足,为选择第三方物流供应商的企业提供更加客观有效的评价选择方法.本文最后的算例结果和专家评审的结果一致,说明采用SE-DEA方法在评价供应商方面是有效的.     

分析企业采购管理中供应商的选择和评价策略

企业的采购管理主要分为两种模式,一种是传统管理模式,一种是准时制管理模式.在企业的采购行为中,企业对于供应商的评价非常重要.这直接关系到与供应商的合作与否.在评价过程中,企业经常利用层次分析法进行评价.通过将不同的问题分为不同的层次,不仅可以实现企业对于供应商的客观评价,还能促进供应商对自我的反思.因此,层次分析法不仅考虑了客观因素,同时也对主观因素进行了分析评价,非常有助于企业形成有效的评价体系.     

风险影响下供应商参与新产品开发的动机研究

供应商参与新产品开发的动机受到风险的影响。在识别、归纳供应商参与新产品开发所面临风险的基础上,应用专家打分法对风险对供应商参与的作用程度进行结构化表述,并应用层次分析法对风险影响下供应商参与新产品开发的动机进行排序。     

模糊层次分析法(FAHP)在供应商评价选择中的应用

人在决策时常有模糊性.然而先前的供应商评价模型却常常忽略了这点.因此本文首先介绍了模糊层次分析法（Fuzzy AHP）,然后提出了实际企业中选择供应商时考虑的因素,最后应用该方法建立了一个供应商模糊评价模型.该模型考虑了人判断的模糊性.在生产实践中,它可以帮助生产企业更准确地选择供应商.     

政府采购的可持续供应商评价准则研究

与供应商建立战略合作关系、提高可持续发展能力是加强政府采购绩效和稳定性的有效手段,应当建立客观、科学的供应商评价和监管机制。结合失效模式、后果分析模型与区间二元语义混合加权距离测度对可持续供应商的评价准则进行风险分析和排序,为评价政府采购的供应商可持续能力提供判断依据。同时指出,政府采购流程中应当动态管理专家库和供应商信息库,制定合适的专家筛选条件,严格把控供应商资格审查,并利用科学方法确定评价准则内容和供应商选择对象。     

供应商战略合作评价模型研究

供应商战略合作评价的目的是选择并建立与供应商的长期战略合作关系,消除供应链上的各种浪费,获得供应链上各企业的"共赢".BP神经网络可以很好地解决供应链复杂性、交叉性以及动态性的特点.文章运用BP神经网络进行供应商战略合作评价模型研究,并以某企业为例,进行了实证研究,将供应商的评价指标作为输入值,将专家综合评价指标作为输出值,经过训练与检验后,该模型可以给出相对客观公正的结果,指导企业与供应商的战略合作.     

How much do online consumers really value free product returns? Evidence from eBay

Consumer return rates have been steadily rising in recent years, resulting in growing costs for retailers who must manage the returns process and the disposition of returned products. This cost pressure is driven in part by extremely generous return policies, such as giving consumers a full refund upon return. Interestingly, this common retail practice of full refunds is inconsistent with the recommendations of many analytical models of returns, which nearly always show that a partial refund is optimal. Such inconsistencies between theory and practice might arise when the decision drivers included in the analytical models do not match the decision drivers in practice. It might also be the case that retailers are overly optimistic about the value that consumers assign to a full refund, and thus assume that the value of such a policy outweighs its costs. In this paper, we use data collected from eBay, where identical products are sold with different return policies, to investigate these open questions in the literature. We analyze both the return policy drivers from the retailer's perspective and the return policy value from the consumer's perspective. Our results suggest that the value of a full refund policy to consumers may not be as large as one might expect, and it also exhibits a large heterogeneity across buyers with different levels of online purchase experience. In addition, we provide empirical evidence for what has long been suspected by online retailers – that a non-refundable forward shipping charge quickly erodes any value that consumers assign to return policies. The generality of our results is limited by the fact that eBay differs from traditional retail contexts in many respects, including the fact that eBay buyers may not be representative of the general buyer population. However, our study of how eBay consumers value free returns provides new insights into an understudied area, and it can serve as a starting point for future studies of the value of return policies in other retail contexts.     

On Lumpiness in the Replacement and Expansion of Capital*

We estimate a model of homogeneous capital investment with two installation possibilities – replacement and expansion using observations at the establishment level. We find that regime switches identified by ad hoc measures of lumpy investment do not adequately distinguish expansionary from replacement activities. In fact, during periods of expansion, firms spend just as much on replacement capital. Also, using the common 20% rule would not assign a spike to almost 65% of all observations that include expansionary investment in this dataset. Finally, replacement although less responsive to fundamentals than expansions cannot be regarded as an autonomous part of investment.     

Conditionally heteroscedastic intensity‐dependent marking of log Gaussian Cox processes

Spatial marked point processes are models for systems of points which are randomly distributed in space and provided with measured quantities called marks. This study deals with marking, that is methods of constructing marked point processes from unmarked ones. The focus is density‐dependent marking where the local point intensity affects the mark distribution. This study develops new markings for log Gaussian Cox processes. In these markings, both the mean and variance of the mark distribution depend on the local intensity. The mean, variance and mark correlation properties are presented for the new markings, and a Bayesian estimation procedure is suggested for statistical inference. The performance of the new approach is studied by means of simulation experiments. As an example, a tropical rainforest data is modelled.     

Time-series properties and predictability of Greek exchange rates

This paper explores the time-series properties and predictability of weekly percentage changes in the Greek drachma exchange rates with respect to the currencies of major trading-partner countries, such as the USA, Germany, the UK, France, Italy and Japan. The analysis is carried out using the EGARCH-M model along with the power exponential distribution. Percentage changes in the Greek drachma with respect to the German mark, the French franc, the Italian lira and Japanese yen are predictable using past information. The volatility of Greek exchange rates is best represented by an EGARCH process and as such is predictable using past volatility measures. Moreover, volatility of the Greek drachma with respect to the German mark and Italian lira positively influences future movements in these exchange rates. The hypothesis that volatility is an asymmetric function of past innovations is rejected in all cases. Following the inclusion of the Greek drachma in the ECU currency basket, its value has been depreciating at a higher rate with respect to the German mark and Italian lira and at a lower rate with respect to the US dollar. Also, its volatility with respect to the German mark, the French franc, and the Italian lira has decreased, whereas its volatility with respect to the US dollar has increased.     

Jane Jacobs' ‘Cities First’ Model and Archaeological Reality

In The Economy of Cities, Jane Jacobs conjectured that the world's first cities preceded the origins of agriculture, a proposition that was most recently revived by Peter Taylor in the pages of this journal. Jacobs' idea was out of line with extant archaeological findings when first advanced decades ago, and it remains firmly contradicted by a much fuller corpus of data today. After a review of how and why Jacobs formulated her ‘cities first’ model, we review current archaeological knowledge from the Near East, China and Mesoamerica to document the temporal precedence of agriculture before urbanism in each of these regions. Contrary to the opinions of Jacobs and Taylor, archaeological data are in fact sufficiently robust to reconstruct patterns of diet, settlement and social organization in the past, and to assign dates to the relevant sites. Our response illustrates how generations of archaeological discoveries have yielded solid empirical foundations for the evaluation of wider social scientific debates.     

后勤保障过程中数据集市模型的研究

本文针对联勤分部实施后勤保障过程中的需求数据相对稳定的特点，提出了后勤保障数据集市模型，定期更新需求数据。探讨了设计数据集市的元数据、模型库和中间组件的过程与关键技术，实现了动态生成数据抽取原则与转换标准的模型；异构数据源中数据的定期抽取与转换，最终为联勤分部指挥中心（联指）制定后勤保障计划提供正确、完整的需求数据。     

Unions and the economic basis of attitudes

Unions make differences to employee satisfaction that correspond to their effects on individual economic advantage. Panel data reveal how changes in economic circumstance and changes in job satisfaction are linked to changes in union coverage. When individuals move into a union covered job they receive a wage mark‐up and express enhanced pay satisfaction. Conversely, those moving from a union covered job on average lose any mark‐up and have significantly reduced satisfaction. Similar findings emerge for working hours. On average individuals prefer shorter hours, something they tend (not) to achieve on moving (out of) into a unionised job, resulting in higher (lower) satisfaction. Switching into union coverage lowers satisfaction with job security, even though coverage has no effect on the risk of unemployment. This is because covered employees suffer greater costs of re‐employment for a given level of unemployment risk, partly because of loss of the union mark‐up.     

机械零件精度设计中形位公差的合理选择

形位公差项目的合理选择与标注是在设计、制造及质量控制等方面优化机械产品质量的前提保障。本文详细分析形位公差的关系,结合实例提出确定形位公差时公差项目、基准、公差数值的选择及在图纸上进行合理标注的方法。