Adding a freight network to a national interstate input–output model: a TransNIEMO application for California

The state of the nation’s infrastructure is the subject of widespread discussion and comment because it is thought to include many deteriorating and unsafe bridges. Ever since the terrorist attacks of 9/11, there has been increasing concern over the extent to which an attack on infrastructure could result in serious economic disruption. This research develops a model to analyze the economic consequences of an attack on a major element of the highway network. We add a freight network to a national multiregional economic impact model and make freight traffic flows endogenous. The use of a sub-national interstate model recognizes that most infrastructure planning is at the state level and most political leaders’ interest is local. We base our approach on the National Interstate Economic Model (NIEMO) and refer to an elaboration that we name Transportation network and the National Interstate Economic Model (TransNIEMO). The new model enables us to study the state-specific and industry-specific economic impacts of some significant changes in the nature of highway freight movements. We tested the model for selected freight movements in and out of California. The results are entirely plausible and encourage us to elaborate and test the model for hypothetical disruptions of freight traffic throughout the US.     

初探阶段性考试在《营销技能综合实训》课程中的实践

在传统考试方式的指导下,教师对于学生学习效果的考核和评估主要是依靠理论笔试的方法,从而导致学生对知识的学习和巩固主要是靠背被动的死记硬背。但是营销类的课程,特别是实训课程除了要求学生牢固掌握理论基础知识以外,更重要的就是理论在实践中的应用。因此,如何有效的考核学生是否已经掌握所学知识是我们教学研究的一个重点问题。本文重点介绍了一种新式的考核方式---阶段性考核方式。针对高职电子商务类学生的特点,初步探索了这种考核方式在营销技能综合实训这门课教学中的应用。     

Incorporating spatial equity into interurban road network design

Methods for the road network design problem, typically, are based on optimization of the network efficiency measures (e.g. network-wide travel time) under a predefined budget. In these approaches, equity issues are not taken into account and, consequently, most of the road improvements are planned next to large cities. Thus, disparities between large and small cities increase, which does not conform to sustainable development objectives. In this paper, to overcome concerns associated with traditional methods, equity is incorporated into the interurban road network design problem. To this end, accessibility concepts are employed. However, unlike previous studies, instead of maximizing the total accessibility, a new definition is proposed for inaccessibility, and total inaccessibility is minimized throughout the network. Using this new definition not only is more compatible with the equity issue, but also helps to eliminate the nonlinearity of the problem. Average travel time to neighboring opportunities is utilized to propose this definition for inaccessibility, which captures the reality more effectively. With the aim of this definition, equity is incorporated into the road network design problem implicitly. This is another improvement over previous methods, where a new term in the objective function or a new constraint is added to include the equity. The proposed model is formulated as a mixed integer linear programming (MILP) problem, where the objective is to minimize the aggregate inaccessibility over all the population centers in the network. To illustrate the application of the model, the Northwest region of the United States is used as the case study. The respective exact solution of the example is found using a commercial solver (CPLEX). This new solution is also compared with the solutions from the traditional methods.     

沪通铁路建设背景下的南通区位形势及交通行业影响预测

沪通铁路建设的帷幕在南通提出加快沿江沿海开发和建设长三角北翼经济中心的背景下正式拉开。沪通铁路工程将对南通地方交通格局及交通运输行业形成重要影响。文章将首先对南通地方交通体系的历史和现状作简要陈述,在此基础上,围绕沪通铁路的建设对完善南通地方交通体系格局的作用展开分析,然后就该工程对南通地方交通行业的影响作综合分析和预测。     

高速磁浮列车技术及其在我国客运交通中的战略地位

高速磁浮列车是当前唯一能达到５００公里／时运营速度的地面交通工具．技术已经成熟．正进入实用运营线建造阶段，将在２１世纪高速客运中发挥重大作用。本文简要介绍了高速磁浮列车技术的发展情况与特点，分析了其在客运交通系统中的地位。从我国国情出发，本文论述了其在我国未来客运交通中的战略地位，并对我国当前发展磁浮列车技术提出了一些建议。     

Dynamic supply chain network design with capacity planning and multi-period pricing

This paper addresses a new problem in designing and planning a multi-echelon and multi-product supply chain network over a multi-period horizon in which customer zones have price-sensitive demands. Based on price-demand relationships, a generic method is presented to obtain price levels for products and then, a mixed-integer linear programming model is developed. Due to the problem intractability, a simulated annealing algorithm that uses some developed linear relaxation-based heuristics for capacity planning and pricing is presented. Numerical results demonstrate the significance of the model as well as the efficiency of the solution algorithm and linear relaxation-based heuristics.     

AN INVESTIGATION OF THE VALUE OF CROSS‐DOCKING FOR SUPPLY CHAIN MANAGEMENT

Cross‐docking is the practice of transferring materials from an incoming shipment directly to an outgoing shipment without storing them at the transfer point. This essentially eliminates the inventory‐holding function of a warehouse and can reduce supply chain costs. We investigate the value of one type of cross‐docking in a variety of supply chain environments.     

A survey on pickup and delivery problems

This paper is the first part of a comprehensive survey on pickup and delivery problems. Basically, two problem classes can be distinguished. The first class, discussed in this paper, deals with the transportation of goods from the depot to linehaul customers and from backhaul customers to the depot. This class is denoted as Vehicle Routing Problems with Backhauls (VRPB). Four subtypes can be considered, namely the Vehicle Routing Problem with Clustered Backhauls (VRPCB – all linehauls before backhauls), the Vehicle Routing Problem with Mixed linehauls and Backhauls (VRPMB – any sequence of linehauls and backhauls permitted), the Vehicle Routing Problem with Divisible Delivery and Pickup (VRPDDP – customers demanding delivery and pickup service can be visited twice), and the Vehicle Routing Problem with Simultaneous Delivery and Pickup (VRPSDP – customers demanding both services have to be visited exactly once). The second class, dealt with in the second part of this survey, refers to all those problems where goods are transported between pickup and delivery locations. These are the Pickup and Delivery Vehicle Routing Problem (PDVRP – unpaired pickup and delivery points), the classical Pickup and Delivery Problem (PDP – paired pickup and delivery points), and the Dial-A-Ride Problem (DARP – passenger transportation between paired pickup and delivery points and user inconvenience taken into consideration). Single as well as multi vehicle versions of the mathematical problem formulations are given for all four VRPB types, the corresponding exact, heuristic, and metaheuristic solution methods are discussed.      

韩资企业经营困境对我国企业“走出去”的启示

自中韩建交以来,韩国利用地理位置、文化背景、生活习惯等方面与中国基本相近的优势,加大了对中国的直接投资,并且获得了巨大的成功。然而,近来部分韩企出现经营困境,某些韩企甚至非法外逃。韩资企业在中国衰落的原因是多方面的。研究这种现象及其产生的原因,对中国企业"走出去",提高应对投资环境变化的能力有重要借鉴意义。