应急物资公路运输路径优化模型的建立及求解

对应急物资运输时效性和可靠性两方面因素进行了数学描述,在分别对两个指标进行了无量纲化处理后建立了线性加权和效用函数模型,在具体算例中又将效用函数变形为关于λ的线性函数,最后通过坐标系作图将分析结果更直观地表达出来,以供应急物资调度人员根据其具体情况要求更方便快捷地选择应急物资公路运输的最优路径。     

飞鸿公司的燃眉之急

飞鸿股份有限公司主要从事国内沿海和国际远洋货物运输业务。2008年,该公司准备增加公司的运力,购买一艘7万吨级的散装二手货船,而该船在二手船市场上国内外买家众多,竞争激烈。飞鸿公司急需在最短时间内融资到1500万美元购买该船,于是,飞鸿公司向Z银行提出融资申请。考虑到从海外购买船只需要等待政府批准,这与公司急需购买船只是相矛盾的,且在当时国际金融危机爆发和中国航运业指数下滑背景下,银行向飞鸿公司提供贷款会有较大风险,而银行又有向客户提供优质服务的使命,怎么办？Z银行做出决定变得非常艰难。该案例属于决策型案例,描述了Z银行经理层的决策场景和特定的决策过程。     

供应链信息流研究综述

通过对供应链信息流相关文献分析,从信息流运作对供应链整个响应时间压缩的影响、信息流的研究内容和研究方法三个方面,对该领域研究进行分析总结,并就进一步研究提出展望。     

Restricted forecasting with VAR models: An analysis of a test for joint compatibility between restrictions and forecasts

A restricted forecasting compatibility test for Vector Autoregressive Error Correction models is analyzed in this work. It is shown that a variance–covariance matrix associated with the restrictions can be used to cancel out model dynamics and interactions between restrictions. This allows us to interpret the joint compatibility test as a composition of the corresponding single restriction compatibility tests. These tests are useful for appreciating the contribution of each and every restriction to the joint compatibility between the whole set of restrictions and the unrestricted forecasts. An estimated process adjustment for the test is derived and the resulting feasible joint compatibility test turns out to have better performance than the original one. An empirical illustration of the usefulness of the proposed test makes use of Mexican macroeconomic data and the targets proposed by the Mexican Government for the year 2003.     

The mean-variance investment problem in a constrained financial market

This paper extends the mean-variance analysis and the two-fund separation theorem to a market with some constraints, such as, the incompleteness, prohibition of short-selling, and partial information, with stochastic interest rate, and with stochastic volatility for risky assets. By maximizing a quadratic utility of terminal wealth, we show that the efficient frontier for the problem is a straight line in the mean-standard-deviation diagram. The quadratic utility function exhibits mean-variance efficiency. Our results apply to portfolios of claims in a single period, multiperiod, and continuous time.     

Globalization,employment relations and human resources indicators in ten developed market economies: international data sets

This paper provides statistical information on internationalization, human resources and labour market outcomes in ten important developed market economies (DMEs). Such data are useful for practitioners and academics who are interested in international HRM. The article's aim is to provide easily accessible statistical tables of selected characteristics, which can be used to draw initial comparisons between countries and to test competing accounts of the impact of globalization on national patterns of employment relations. It includes standard sources so readers can elaborate and update these data.     

光缆自动化监测系统

介绍了远程光纤监测系统(RFTS)的结构、测试方法及其与电信管理网(TMN)的结合情况,并列举出一些典型的RFTS系统以阐明其应用和发展趋势。同时,还讨论了影响光时域反射仪(OTDR)测试精度的要素和消除测试误差通常采用的对策。     

栈桥钢管桩浮冰冲击作用下的有限元分析

本文运用有限元分析软件Midas civil和ANSYS分别建立了栈桥钢管桩的整体及局部有限元模型,分析了在浮冰冲击荷载作用下钢管柱的受力情况,为栈桥检算提供理论依据,同时优化设计方案,保证了栈桥在使用中的安全可靠。     

等概率条件下的转弯型堆垛机作业效率的计算研究

转弯型堆垛机是自动化立体仓库中实现货物自动存取的关键设备,文中对转弯型堆垛机效率问题进行研究。在假定等概率拣取货物的条件下,分别推求转弯型堆垛机的平均单一作业和复合作业循环周期和作业效率的计算公式,并利用华南理工大学仓储综合实验室的基本数据进行了作业效率的实证计算,从而为自动化立体仓库系统的建设设计和有效管理提供依据。     

Airline flight networks, cycle times, and profitability: 2004–2006

This research investigates the relationships between airline flight networks, aircraft cycle times, and carrier profitability for ten large US domestic airlines. We find that direct point-to-point flight networks and short cycle times are operational factors that airlines should exploit to improve profitability. These findings are based on the analysis of 11.9 million flight records from 2004 through 2006. The results contradict earlier research validating performance advantages of hub-and-spoke flight networks. Today, the advantages of passenger consolidation at hub airports are lost to lower aircraft utilization and productivity problems created by the extended cycle times at hubs. We also find that airline operating profit can be increased by improving the efficiency of the aircraft turnaround process and decreasing aircraft fleet complexity. This research also provides an estimate of the marginal opportunity cost of ground time. A 1-min reduction in aircraft fleet ground time increases the average sized carriers’ operating income by $12 to $18 million.