露天边坡工程及FLAC数值分析

以高西沟露天煤矿的西北边帮作为研究对象,运用FLAC3D数值模拟软件,经过数值计算得到边坡安全系数为1.57,其与工程类比法计算得到的数值差不多,知该数值分析方法不仅能快速、准确的算出边坡的稳定性系数,还能够形象的描绘边坡的滑移临界场,是一种有效的边坡稳定性分析的方法。     

Are margins more procyclical in concentrated industries?

In a series of recent papers, Domowitz, Hubbard and Peterson (DHP) have explored the temporal behavior of price-cost margins in a panel of 284 four-digit SIC industries. This paper reexamines DHP's apparent finding of more procyclical margins in concentrated industries, concluding that it is not robust. The result appears to arise from long-run trend correlations between margin and demand levels, rather than from short-run cyclical effects. Consistent with DHP, prices are found to be stickier and unit costs more countercyclical in concentrated industries. However, (1) an omitted variables bias is uncovered which substantially reduces the estimated cyclical effect on costs, and (2) prices are found to be more flexible in low concentration, low-PCM industries than DHP estimate. With prices more responsive to growth in demand and a countercyclical effect on cost of substantially lower magnitude, margins are thus estimated to bemore procyclical in less concentrated industries. This finding explains the relative rise in low concentration margins in the sixties which, in turn, helps account for the declining significance of the cross-sectional concentration-margins relationship.I would like to acknowledge helpful comments from Roy Rotheim, and two anonymous reviewers.     

基于关键线路的改进挣值法模型

传统挣值法在我国工程项目管理应用中还存在一定的缺陷,有时不能准确反映工程实际完成情况,给项目管理带来一些困难。为了使挣值法在工程项目管理中发挥积极作用,通过模拟工程案例,着重指出传统挣值法管理技术忽略了关键线路上工序的进度对于工程项目总进度的决定性作用,导致判断失误。在此基础上,提出了解决的问题的方法,通过对关键线路的挣值分析,建立了基于关键线路的改进挣值法模型和判断标准。     

Motivating a Productive Discussion of Normative Issues Through Debates

In this article, the author presents a way of using in-class debates to discuss contentious issues and help students develop critical thinking skills. Three elements were incorporated into an undergraduate public finance course: a presentation of ethical approaches in order to formally discuss normative issues, class debates which required students to work in groups and imaginatively occupy a perspective with which they were not personally comfortable, and individual reflection which forced students to reconcile their beliefs with academic evidence. The results show that even if students did not change their perspectives on economic policy, the reasons why they have those perspectives did change to be based in academic theory and evidence and not their blind adherence to specific political platforms.     

Understanding the factors affecting the adoption of the Internet of Things

The Internet of Things (IoTs) is widely considered as one of the most important infrastructures for promoting economic development and technological innovation. The purpose of this study is to find the key factors influencing IoT adoptions, specifically in Taiwan’s logistics industry. In this study adopts a model which is a hybrid of technology, organisation and environment (TOE) and the decision-making trial and evaluation laboratory method (DEMATEL) to evaluate the complex factors influencing the adoption of IoT. The study employs the TOE framework as a basis to develop a general evaluation framework, and the DEMATEL technique conceptualises a structural model and then identifies the causal relationships among factors through a cause-effect relationship diagram. Finally, we also divided the complex influencing factors into cause and effect groups to better clarify the causal relationships for decision-making, to ensure the efficiency of IoT adoption.     

大学生网络购物忠诚度关键影响因素实证研究

大学生网络购物忠诚度的提高对网络零售企业利润的增长有重要的影响。通过问卷调查和统计分析,找出影响大学生网络购物忠诚度关键因素,采取相应对策措施,有利于提高大学生网络购物忠诚度,拓展网络商家的市场空间。     

钢材期货推出对于钢铁产业链的影响研究

本文从钢铁期货推出后对钢铁企业及其上下游的影响作了系统深入的分析,提出了钢材期货推出后应注意的问题,并得出结论:整体而言,钢材期货的推出利大于弊,是适应目前经济发展的合理举措。     

基于生态视角下的建筑业创新问题模拟研究

目前关于建筑行业创新投入、技术扩散、对建筑产业整体收益、产业集中度的影响难以用实际数据分析,因而从个体企业行为角度出发,根据多智能体理论,使用多主体仿真平台(Netlogo)建模平台,建立我国建筑业的交易行为互动流程,模拟运行建筑产业创新行为,观察并分析论证创新使产业集中度产生波动,创新企业数量与产业收益是U型关系,技术扩散速度对产业收益有极大影响的结论。