客运专线、高速铁路异物侵限监测方案优化

结合国内客运专线、高速铁路异物侵限监测系统的应用现状,详细分析了我国客运专线、高速铁路异物侵限监测系统监测手段、监测网安装方式、监测网防护对象、监测范围等,明确提出了适合我国客运专线、高速铁路异物侵限监测系统的建设方案优化建议。     

电子商务对国际贸易的影响

本文从以下几个方面对电子商务对国际贸易的影响进行了讨论:电子商务使国际贸易运行方式和环境发生重大变化,电子商务使国际贸易经营主体的战略发生重大变化,电子商务使国际贸易经营管理方式发生重大变革,电子商务促进世界技术贸易的发展,提出了电子商务必将创造巨大的效益和机会。     

短时记忆与外语学习

短时记忆在外语学习中起着十分重要的作用。本文论述了短时记忆的特点及与长一时记忆、工作记忆的关系，探讨了短时记忆与外语学习的关系，最后提出了提高外语学习的一些方法。     

影响我国出口贸易持续增长的科技因素及其对策

目前,大力推进科技兴贸,采取切实可行的措施,充分发挥知识资本在对外贸易中作用,使我国出贸易的增长方式由数量增长型变为科技进步型,已成为二十一世纪中国经济生活中一个亟待解决的问题。分析了影响我国出口贸易持续增长的科技因素及对策。     

新时期如何加强垦区道路运输行业管理

分析了目前道路运输行业存在的矛盾和问题 ,针对新时期的形势和任务 ,提出了要保证垦区道路运输持续发展 ,必须从优化行业内部结构 ,强化管理职能 ,注重法制及科技创新入手。     

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阐述了中国民航总局近十年来的体制与管理的变革，介绍了中国民航当前采取的五项重大举措.即建立精干高效的行业监管体制和队伍；中国民航由九家航空运输企业组成国内三大航空公司的建设；机场的管理体制和走向市场化；以及改革民航运输的空管制度等.特别讨论2008年北京奥运会、2010年上海世博会等重大活动的空运管理问题.     

Selection of Mergers and Acquisitions by Foreign Capital in Open Economies

IntroductionIn recent years, large quantities of multinationalcorporations ( MNCs) compete for publicly tradedcompanies in mainland china, which gives domesticfirms more alternatives, and increases their economicbenefit. With their different impacts on me…     

内外贸同船运输下长江经济带穿梭巴士网络优化

为研究内外贸同船运输政策对航运企业布局长江经济带穿梭巴士网络的影响，本文允许同一船舶同时运输内贸集装箱和外贸集装箱，以总运输成本最小化为目标，考虑服务频率、多航次、时间窗、载重量等约束，构建基于轴辐式的长江经济带集装箱穿梭巴士网络优化模型。针对该模型，本文设计了包含5种破坏算子和2种修复算子的自适应大邻域算法求解模型，并选取上海和长江干线19个港口间的内贸集装箱运输和外贸集装箱运输进行实证分析。研究结果表明： 实施内外贸同船政策可节约23.6%的总运输成本，提升平均舱位利用率至87%。该政策改变了原有穿梭巴士的网络结构，直达航次比例增加17%，加快了穿梭巴士的周转。同时，相比于设置1个枢纽港，长江经济带下游将南京港和太仓港共同设置为枢纽港更有利于中上游内外贸集装箱的中转，可节约6%~17%的总运输成本。     

A game model of international trade,transport costs,invasive species,and protocol compliance

We study the duopolistic interaction between two monopolists located in two different countries who sell an imperfect substitute good in two markets. The traded good is transported between the two nations on ships using solid wood packing materials (SWPMs) and hence the presence of one or more invasive species is a problem. We use a game model to analyze this interaction in three steps. First, we study the benchmark case of autarky or no trade between the two nations. Second, we introduce transport costs and then study the effect of free trade on the profits of the two monopolists. Finally, we suppose that invasive species are present in the SWPMs. This fact requires compliance with an environmental protocol. We model this compliance by increasing the transport costs associated with trade and then demonstrate that a version of the so called Porter hypothesis holds. In other words, we show that compliance with a cost increasing environmental protocol can give rise to higher profits for the two monopolists under consideration.     

Overview of missing physical commodity trade data and its imputation using data augmentation

The physical aspects of commodity trade are becoming increasingly important on a global scale for transportation planning, demand management for transportation facilities and services, energy use, and environmental concerns. Such aspects (for example, weight and volume) of commodities are vital for logistics industry to allow for medium-to-long term planning at the strategic level and identify commodity flow trends. However, incomplete physical commodity trade databases impede proper analysis of trade flow between various countries. The missing physical values could be due to many reasons such as, (1) non-compliance of reporter countries with the prescribed regulations by World Customs Organization (WCO) (2) confidentiality issues, (3) delays in processing of data, or (4) erroneous reporting. The traditional missing data imputation methods, such as the substitution by mean, substitution by linear interpolation/extrapolation using adjacent points, the substitution by regression, and the substitution by stochastic regression, have been proposed in the context of estimating physical aspects of commodity trade data. However, a major demerit of these single imputation methods is their failure to incorporate uncertainty associated with missing data. The use of computationally complex stochastic methods to improve the accuracy of imputed data has recently become possible with the advancement of computer technology. Therefore, this study proposes a sophisticated data augmentation algorithm in order to impute missing physical commodity trade data. The key advantage of the proposed approach lies in the fact that instead of using a point estimate as the imputed value, it simulates a distribution of missing data through multiple imputations to reflect uncertainty and to maintain variability in the data. This approach also provides the flexibility to include fundamental distributional property of the variables, such as physical quantity, monetary value, price elasticity of demand, price variation, and product differentiation, and their correlations to generate reasonable average estimates of statistical inferences. An overview and limitations of most commonly used data imputation approaches is presented, followed by the theoretical basis and imputation procedure of the proposed approach. Lastly, a case study is presented to demonstrate the merits of the proposed approach in comparison to traditional imputation methods.