矿井通风三维可视化系统及优化

系统建立了三维仿真框架,建立了三维空间属性模型和非空间属性模型,分别对空间数据和非空间数据进行储存和管理。并建立了Hardy-Cross迭代模型和离散反馈型神经网络模型优化通风网络模型。并以C#语言来实现系统的功能。     

高职铸造专业实训改进研究与实施

为了提高高职学院铸造专业学生实训效果,通过消失模铸造改进传统木模手工造型,既提高了学生实际动手能力,又使学生掌握了该门先进铸造技术,增强了学生就业竞争能力。     

Linking customisation of ERP systems to support effort: an empirical study

The amount of customisation to an enterprise resource planning (ERP) system has always been a major concern in the context of the implementation. This article focuses on the phase of maintenance and presents an empirical study about the relationship between the amount of customising and the resulting support effort. We establish a structural equation modelling model that explains support effort using customisation effort, organisational characteristics and scope of implementation. The findings using data from an ERP provider show that there is a statistically significant effect: with an increasing amount of customisation, the quantity of telephone calls to support increases, as well as the duration of each call.     

Exploring the impact of the physical conditions of mannequin displays on mental simulation: An embodied cognition theory perspective

This study examines how mannequins' physical conditions of display height and distance are related to consumers’ shopping motivations in generating mental simulation resulting in purchase intention. A 2 × 2 x 2 between-subjects lab experiment (n = 249) was conducted to address this question. The results reveal a significant three-way interaction effect of display height, distance, and shopping motivation. Specifically, it is found that for those with a dominant hedonic shopping motivation, a mannequin displayed up high generates greater mental simulation than one displayed down low, but for those with a dominant utilitarian shopping motivation, a mannequin displayed high and close to consumers generates greater mental simulation than one displayed low and close to them. This study also reveals that mental simulation mediates the influence of the interaction effect of “display height x distance,” moderated by shopping motivation, on purchase intention. Important theoretical and practical implications for retail managers are discussed.     

Saddlepoint approximations to the mean and variance of the extended hypergeometric distribution

Conditional inference on 2 x 2 tables with fixed margins and unequal probabilities is based on the extended hypergeometric distribution. If the support of the distribution is large, exact calculation of the conditional mean and variance of the table entry may be computationally demanding. This paper proposes a single‐saddlepoint approximation to the mean and variance. While the approximation achieves acceptable accuracy for ordinary practical purposes, an alternative saddlepoint approximation is provided that gives much closer to exact results. It improves the accuracy of current approximations to up to more than four powers of ten.     

外资影响我国出口产品质量的差异性研究:从一个地区市场化程度的视角

我国正在经历从出口成本优势向质量优势转型的重要时期。外资对我国出口产品质量的影响及其差异性成为政府和学界关注的问题。本文从市场化水平、政府与市场的关系以及知识产权保护等三个方面检验了制度因素对外资质量溢出的影响。回归结果表明:(1)市场化程度低确实抑制FDI质量溢出;(2)政府干预对外资质量溢出效应产生了负面影响。在低市场化程度或者高政府干预样本组中,FDI质量溢出效应不显著;(3)知识产权保护对FDI质量溢出的影响程度非常有限。本文的结论为政策制定者提供了决策参考依据。简政放权、降低企业面临的行政成本是促进我国本土企业改善其出口产品质量的重要抓手。     

基于fluent紊流幂律流体偏心环空数值模拟研究

为解决常规钻井水力学公式对偏心流场计算结果与实际有所差别的问题,揭示大位移井偏心环空水力行为规律,基于fluent软件对幂律钻井液偏心环空紊流流动进行了数值模拟研究,分析偏心度、稠度系数、流性指数、屈服值、钻杆与钻头组合对流动规律的影响.结果表明,随偏心度、稠度系数、流性指数、屈服值、钻杆与钻头尺寸比例的增大,环空中宽间隙处的流速、压力逐渐增大,而窄间隙处的流速、压力逐渐减小.     

数控仿真软件在数控教学中的应用——以车削零件加工为例

为了提高《数控机床与编程》课程的教学质量,把数控仿真软件应用引入到课堂教学,并结合车削零件加工,展示数控仿真软件整体加工过程,结果极大提高学生课堂的兴趣,提高了教学效果,也提高学生的数控编程能力和数控机床操作能力,保证了教学质量。     

Technology‐push,market‐demand and the missing safety‐pull: a case study of American Airlines Flight 587

Through a critical case study of the crash of American Airlines Flight 587, this paper draws upon ‘the Social Shaping of Technology’ (SST) approach to offer a reconceptualisation of the technology‐push and market‐demand model for High‐Reliably Organisations (HROs), providing support for a third factor, called here a ‘safety‐pull’. A safety‐pull is defined as organisationally supported reflexivity in which technology innovators and frontline operators collaborate to consider the potential implications of adopting new technologies in HROs and the complex ways this change may impact human operators' work performance, often in risky and unanticipated ways. In contrast to accidents occurring solely as the result of individual operator error, analysing the safety‐pull provides a way to tease out the wide range of factors that can contribute to HRO failures and offers a new SST perspective through which to examine high‐risk operations.     

基于VVA的多分辨率交通仿真建模过程评价框架研究

文章从多分辨率交通仿真的建模过程入手,研究了系统仿真的校核、验证与确认(Verification Validation Accreditation,VVA)过程评价的原理。在此基础上,提出了基于VVA的多分辨率交通仿真建模的过程评价框架。通过研究仿真系统生命周期中的一系列活动来评价研究结果的正确性和有效性,提高了系统的可信性,使仿真系统能够满足实际应用的需要。